Ground Glass - Cutting and Cleaning Tips
by Robert Monaghan
Related Postings
Date: Wed, 24 Dec 1997
To: rollei@mejac.palo-alto.ca.us
From: Mark & Sue Hubbard <hubbard@humboldt1.com>
Subject: [Rollei] How to Clean Ground Glass
Dear Rollei List,
I'm indebted to Mario Nagano and Richard Knoppow for sharing their
knowledge and experience with me.
For those interested in their responses to my question of how to clean
the
ground glass on my new old Rolleiflex 3.5E, here is what they wrote:
####
Hi Mark,
First of all, congratulations for your new acquisition. Both my 3.5
EVS and a 2.8E have a non-removable hoods and I passed by the same
experience. If I can give you some advices, here it goes:
1. Be extremely careful when you remove the screws. They are made
of some kind of "softer-than-steel" metal (maybe bronze, so that they
are easily marked.
2. If you look at the bottom part of the hood (removed) you'll see
that the ground glass is fixed by two spring-metal parts. Remove the
screws that fix these parts on the hood and the screen are free.
3. MOST IMPORTANT: Check if your screen are really made of glass.
If it's acrylic be aware of not using any kind of chemical that
attacks plastic, like ammonia or ether solutions.
> Best wishes for the holidays and new year,
The same to you. :-)
Mario Nagano
nagano@canalvip.com.br
nagano@mail.regra.com.br
####
Once you have the hood off you will find the ground glass is held in
place by a couple of flat strip springs at top and bottom. The springs in
turn are held in place by fitting into little slotted pockets. Push the
center of the strip gently toward the ground glass to release it from its
pocket. The GG will come out. It lens cleaner or Windex should work. If
the GG is very dirty you may want to soak it for a few minutes in a
solution of dishwashing detergent.
Blow out the mirror compartment with air. Clean the back of the viewing
lens. The mirror can be cleaned by swabbing it with 91% Isopropyl alcohol
(from the drugstore) or with high grade Acetone. Use a lintless swab and
use each just once. Photographic Solutions sells saturated swabs for just
this job.
Schneider of America has a list of serial numbers with dates on
their web site: http://www.schneideroptics.com
----
Richard Knoppow
Los Angeles,Ca.
dickburk@ix.netcom.com
From: nagano@canalvip.com.br (Mario Nagano)
To: rollei@mejac.palo-alto.ca.us
Date: Thu, 25 Dec 1997
> Date: Wed, 24 Dec 1997
> To: rollei@mejac.palo-alto.ca.us
> From: Mark & Sue Hubbard
<hubbard@humboldt1.com>
> Subject: [Rollei] How to Clean Ground Glass
> Dear Rollei List,
>
> I'm indebted to Mario Nagano and Richard Knoppow for sharing their
> knowledge and experience with me.
>
> For those interested in their responses to my question of how to clean the
> ground glass on my new old Rolleiflex 3.5E, here is what they wrote:
(...)
> It lens cleaner or Windex should
> work. If the GG is very dirty you may want to soak it for a few
> minutes in a solution of dishwashing detergent.
> Blow out the mirror compartment with air. Clean the back of the
> viewing
> lens. The mirror can be cleaned by swabbing it with 91% Isopropyl
> alcohol (from the drugstore) or with high grade Acetone. Use a
> lintless swab and use each just once. Photographic Solutions sells
> saturated swabs for just this job.
Hi people,
Since Richard mentioned some chemical solutions for cleaning
cameras, here's an interesting recipe I found at Canon FD
Mailing list:
Re: Restoring White letters on an A-1
Greg Tims (gtims@ix.netcom.com)
Thu, 24 Jul 1997
Alkemyst wrote:
>
> What is a good procedure to brighten up/restore the white lettering
> on a Canon A-1?
I feel pretty silly giving this advice to a pharmacist (big assumption
on my part from your "handle"), but here goes: 50% Hydrogen Peroxide
(H202) and 50% Ammonia (NH3 - the non-sudsing, household stuff.) This
makes a very weak, non-hazardous Ammonium Hydroxide solution. Moisten
the end of a Q-Tip with it and scrub away.
By the way, the above solution is an absolutely OUTSTANDING lens
cleaning solution (as recommended by Schneider Optics); far better
than any commercial lens cleaning solution as it leaves no film,
easily removes any grease/oil marks (e.g. finger prints - yeah, I'm a
klutz) and does no harm to lens coatings. I was totally stunned with
the results the first time I used it on a lens. Oh yeah, its also
exponentially less expensive than "Lens Cleaning Solution."
--
Greg Tims "I doubt there is anything more disturbing
Gig Harbor, WA USA than a sharp image of a fuzzy concept."
gtims@ix.netcom.com - Ansel Adams
(1902-1984)
Regards,
Mario Nagano
nagano@canalvip.com.br
nagano@mail.regra.com.br
From: "Dan Post" <dwpost@email.msn.com>
To: <rollei@mejac.palo-alto.ca.us>
Subject: [Rollei] Re: Ground Glass Cleaning
Date: Thu, 25 Dec 1997
Richard,
Or should I address you as Photo-Guru!? Thanks for the info on cleaning the
ground glass; your info is always to the point and useful. I am grateful
that you are here to share your wealth of knowledge.
BTW- if any of you use the 'micro-fibre' cloths to clean lenses, and
wondered why the little 7x7 inch cloths are so expensive, well, I
found out!
I asked the daughter of a friend who is a textile designer about getting the
fabric- and you can get microfiber fabric at any upscale fabric store that
caters to dressmakers; but it is about $12 a yard! I bought a yard, cut it
into one foot squares that I keep in zip-lock bags ( to keep them clean in
the camera bag) and they are great for glasses, lenses, and even bathroom
mirrors! Seems to pick up smudges rather than smearing them!
Cheers
Dan'l
Date: Thu, 25 Dec 1997
From: "R. Bender" <rjbender@apci.net>
To: rollei@mejac.palo-alto.ca.us
Subject: [Rollei] cleaning TLR mirrors
Richard Knoppow <dickburk@ix.netcom.com> writes:
> Blow out the mirror compartment with air. Clean the back of the viewing
>lens. The mirror can be cleaned by swabbing it with 91% Isopropyl alcohol
>(from the drugstore) or with high grade Acetone.
Some of those mirrors have the silvering on the top surface rather than
on the back side of the glass. I wouldn't use any harsh chemicals and I
wouldn't rub too hard when cleaning.
R. Bender
(A Mamiya, Nikon and Rollei user. Formerly known as
Mamiya645@aol.com.)
Date: Thu, 25 Dec 1997
To: rollei@mejac.palo-alto.ca.us
From: Richard Knoppow <dickburk@ix.netcom.com>
Subject: Re: [Rollei] cleaning TLR mirrors
you wrote:
>On Wed, 24 Dec 1997 Richard Knoppow
><dickburk@ix.netcom.com> writes:
>
>> Blow out the mirror compartment with air. Clean the back of the viewing
>>lens. The mirror can be cleaned by swabbing it with 91% Isopropyl alcohol
>>(from the drugstore) or with high grade Acetone.
>Some of those mirrors have the silvering on the top surface rather than
>on the back side of the glass. I wouldn't use any harsh chemicals and I
>wouldn't rub too hard when cleaning.
>
>R. Bender
>(A Mamiya, Nikon and Rollei user. Formerly known as Mamiya645@aol.com.)
>
>
Early mirrors may be silvered. Some caution is wise before cleaning
them. Postwar mirrors are all likely to be aluminized and are pretty
tough. Generally, the first-surface mirrors used in reflex cameras of all
types may be silvered with a coating of lacquer on top. Often the lacquer
get discolored (yellowed). I haven't direct experience with renovating
this coating and, again generally, the older silvered mirrors are often
tarnished. I wonder if anyone knows of anyone who can recoat them or
aluminize them. Perhaps John Van Stelten?
----
Richard Knoppow
Los Angeles,Ca.
dickburk@ix.netcom.com
Date: Fri, 26 Dec 1997
To: rollei@mejac.palo-alto.ca.us
From: "R. Peters" <torx@nwrain.net>
I have not tried to resilver a mirror, but I have read that it isn't too
difficulte. It is a routine part of making astronomical telescopes.
I understand that a solution of silver nitrate is used, the item is laid in
the bottom of the "dish", and another chemical is added to precipitate the
silver onto the mirror. At least it din't sound that hard.
Question for Tony: do you cut your own mirrors, or do you take them to
a glass shop? My attempts at cutting glass have
been...'shattering'...experiences...
bob
Date: Fri, 26 Dec 1997
To: rollei@mejac.palo-alto.ca.us
From: Marc James Small <msmall@roanoke.infi.net>
Subject: Re: [Rollei] Silvering Mirrors
Bob Peters wrote:
>I have not tried to resilver a mirror, but I have read that it isn't too
>difficulte. It is a routine part of making astronomical telescopes.
>
Well, it WAS a routine part of telescope making until aluminizing mirrors
got to be readily and inexpensively available. Silvering has pretty much
died out, now, save for some limited photographic uses where the frequency
response of silver is preferable to that of aluminium.
A FIRST-SURFACE silver coating in an urban environment might last one year
or five years or ten years, while aluminium coatings simply go on and on,
as they form a thin coating of AlO2 on the surface which serves to protect
the aluminium coating itself. I have a 1980 Meade 1037 SCT: when I
contacted them some years back about recommended serving to the optics,
they gently replied that if the mirror was bright and shiny, let it be
--
aluminium is THAT durable.
Rollie only used first-surface mirrors, I recall, on its Prewar cameras,
which is why so many of these have dim VF: the silver is long gone from
the front of the mirrors, and only the natural reflectivity of the glass is
now bouncing the image up. Postwar, F&H went to second-surface mirrors:
in general, cleaning the front surface of this glass every decade or so
should suffice.
I do have instructions, in some of my older astronomy books, on how to
silver a first-surface mirror. It is a relatively simple process but
involves some Really Nasty Chemistry. I will post the instructions in a
day or three if anyone wants them.
Now, the question which springs to my mind is why not have the mirrors
aluminized and be done with the problem for a half-century or so? This can
be done commercially for $25 or $50.
Marc
msmall@roanoke.infi.net
[Ed. note: Great tip on making ground glass!]
rec.photo.equipment.large-format
From: levistarks@aol.com (Levistarks)
[1] ground glass experiments
Date: Wed Feb 25 1998
After a few atempts at making my own ground glass, I think I stumbled onto the
right combination:
I've tried using a sandblaster, sandpaper, and abrasive grit. the abrasive
grit really works. now for the clincher- I tried a varity of different kinds
of grit, but most leave you with a very smooth dull milky surface. pretty much
like a standard glass off of an old calumet view camera. Last Christmas I
bought my kid a nice rock polishing set, the rock shop sells the polishing
grit seperatly. I got 4 different grits. after trying the two finest grits,
and not being satisfied with the results I figgured why not try a coarser
grit?
So I tried the silicone carbide 220 grit.
This stuff seems really coarse, but makes the G.G. SPARKLE! I was making a
5x7 glass, so I had 2 pieces of single strength cut (.50 a piece) and used
plenty of water with a pinch of grit. The trick is to rinse off both pieces and
inspect each piece as soon as the abrasive starts to break down (get powdery)
and start with fresh grit each time. that way you see which areas need more
work, and the fresh sharp abrasive cuts little facets into the glass surface.
Yes it is just slightly coarser than my other G.G. But just holding a lens in
front of it and looking at a lightbulb about 10 feet away it is clearly
brighter, and with the naked eye I can read the small writing on the bulb with
either G.G. So I don't believe that will be a detriment. Anyway I now have two
(did I forget to mention, you get a spare G.G. using this method) Bright ground
glass pieces. Hopefully I will be trading for an 8x10 field camera soon, I
can't wait to make a glass for it. I will probably get a fresnel from Edmunds
and try that in various locations.
That's it for now.
Levi. in St. Louis
rec.photo.equipment.large-format
From: "Richard Davis" DrDagor@worldnet.att.net
[1] Re: Film plane distance?
Date: Mon Apr 27 1998
> The important thing is that the film, when the holder is inserted, be atthe
> same plane as the front of the groudnglass.
>
> Bob Gurfinkel
I'll second this. I changed ground glass in a camera and couldn't figure
out why things went fuzzy.
There was an excellent article on this in View Camera about a year ago.
The author took about 7 one dollar bills with sequential serial numbers,
put them in a holder so that each bill was like 1cm in front of the other,
and then focused on bill #4 (in the middle). When he developed the print,
if bill #4 wasn't the sharpest, he knew the film plane and ground glass
plane were different. And by seeing which bill was in focus, he knew which
direction the error was in and had a clue about magnitude.
For a really accurate test, use $10 bills.
rec.photo.equipment.large-format
From: "M. J. Rossano" mrossano@friend.ly.net
[1] Re: How to make sure the focus glass match the film plane
Date: Sat Jul 11 1998
If you own or can borrow a 0-1" depth micrometer, and are using a camera
with an international or graflok back, you can measure the depth of the
groundglass with respect to the seating surface of the groundglass frame,
at each of the corners. It should be 0.191" (4.85mm) for a 4x5 camera. A
measurement of your film holders (empty) should give a depth from seating
surface to film backing plane of 0.199" (4.87mm). A variation of +- 0.002"
(0.05mm) should provide satisfactory results. Greater variation will be
tolerable with slow lenses or small aperatures. As a rule of thumb,
acceptable depth of focus for the 4x5 format is about (0.001") * (f
number). If your total alignment error is half this value or less, you'll
never see the difference.
rec.photo.equipment.large-format
Date: Sat Jul 11 1998
From: Dave nospam@pacifier.com
[1] Re: How to make sure the focus glass match the film plane ?
The easiest way is to borrow some dial calipers from a friend
(machinist, engineer etc.). Then take a depth measurement on the film
holder from the surface that meets the camera back to scrap piece of
film in the holder. Then take adepth measurement on your groud glass
back from the surface of the glass holder that rests on the camera to
the frosted side of the glass. Sometimes making the measurement is
tricky, but this is the way to be really sure.
There is a standard depth for film holders, but I don't remember the
exact number. The few times I have seen a discussion of the "standard
depth" there has been a fair amount of disagreement. So, the best way is
to measure.
Another way is to take a picture of a ruler (that has high contrast like
a white tape measure with black numbers) that is laying on a flat
surface. Arrange the camera so you are looking down the ruler from one
end at a fairly steep angle. Since you are looking down the ruler and it
is angled to the camera, there will be only one place on the ruler that
is in perfect focus (since you won't do any tilting or shifting, just
take it with the camera at nuetral position). Pick a number on the ruler
and focus on it very carefully. Remember the number, and take the
picture. Develop the film and if the number is in perfect focus.....your
film holder is calibrated well. Shoot the picture fairly wide open (like
f8 or larger) so you have limited depth of field. This is also useful
for verifying that your polaroid holder is in agreement with the rest of
your holders and glass.
Credit goes to Jay Bender on the latter method as this is the way you
check calibration on the Bender view camera kit.
By the way, this is a really important thing to check. However, I would
guess most cameras are pretty close. If you do any really demanding
macro work, it would be really critical though.
Regards,
Dave
Ching-jen Cheng wrote:
> Just come up to my mind ..
>
> we focus on the focus glass,assume it will appears
> sharp on the films. How can we make for sure ?
> Trial and error ?
--
I hate spam! reply address is:
dpayne at pacifier dot com
Dave Payne
rec.photo.equipment.large-format
From: "Richard Davis" DrDagor@worldnet.att.net
[1] Re: How to make sure the focus glass match the film plane
Date: Tue Jul 14 1998
But there was an excellent article bout this in either View Camera or Photo
Techniques within the past two years.
What the author of the article did was to make a little jig that held
dollar bills together in a deck, with the serial numbers all showing. I
think he used something like foam core as a spacer between the bills, and
used about $7 worth. He also used new bills with consecutive numbers.
Then he focused wide open on bill #4, and then looked to see which bill was
in focus on the film. I thought this was pretty clever.
From: k4sb@niia.net
Newsgroups: rec.photo.equipment.large-format
Subject: Re: Cleaning groundglass
Date: Wed, 30 Sep 1998
> I forgot to add that this same method can be used to remove irritating grid
> lines in some cases. If this is likely to be a problem the tip off would be
> that the grid lines are probably already somewhat damaged.
>
> SKG
Deardorff Gridlines are silkscreened on. Over the years many different types
of laquer were used. All wash off. That is, the water/soap gets under the
lines and they peel off. I made some lined GG with a epoxy base. They dont
come off !! Ken Hough Deardorff restorations k4sb@niia.net
rec.photo.equipment.large-format
From: "keith" bogus-email@.com
[1] another source for ground glass
Date: Thu Jan 14 1999
There have been many messages regarding sources for ground-glass (buying it
from Edmund Scientific, making it yourself, ...). Here's another low-cost
alternative for those of you looking for replacement ground-glass:
Go to your local stained-glass supply store (they sell supplies and glass
for people making lampshades and things like that). They sell acid-etch
glass, which is clear glass frosted on one side by etching with
hydroflouric acid cream. It is perfectly smooth and very fine-grain. Some
ordinary window glass shops may carry it too, but not all of them have it
and the window glass shops usually have a minimum labor charge for cutting
the glass, where the stained-glass shops are used to selling small pieces
of glass and will probably cut it for you for free. If you go to a window
glass shop, dont let them try to convince you that sand-blasted glass is
the same thing (it's not). Sandblasted glass is far too rough and uneven,
even if they use the fine aluminum oxide powder.
As a comparison (OK, I was bored during the holidays), I also used the
method described on http://www.multiboard.com/~joneil/bender.html to make
my own. (it's actually suprisingly fast and easy and works very well). You
can find the grit at places that sell lapidary supplies (rock-tumbling and
jewlery-making). Using 600-grit makes extremely fine-grain glass. Using 280
grit also works, but the grain is quite a bit coarser. The grain on the
acid-etch glass appears to be somewhere in-between when looking at it using
an 8x loupe, I would estimate it is equivalent to 400-grit. You could also
buy the acid-etch kit to make it yourself, but hydroflouric acid is
extremely nasty stuff and it's cheaper just to let them do it.
As for cost, acid-etch glass is less than half the cost of grinding your
own glass. Four 4x5 pieces of 2mm acid-etch glass at the local
stained-glass shop were $1.40 each including cutting, while the total cost
of making my own using was about $20 ($16 for a pound of 600 grit and $4
for a square foot of glass). This is a lot less than paying 50 or 60
dollars for an 'offical' replacement.
Also, if you want to put nice grid lines on, Letraset makes a set of dry
transfers called 'lines', and another one called 'squares'. They do stick
to the frosted side of the glass, but not very well. It's probably best
just to use a fine-point felt pen. Radio Shack has something similar to
Letraset, called 'etch-resist dry transfers', for masking circuit traces
when making printed-circuit boards. It is stickier than Letraset, but can
leave glue sticking to the glass if you're not careful.
Enjoy.
keith.
rec.photo.equipment.large-format
From: sanking@hubcap.clemson.edu (Sandy King)
[1] Re: another source for ground glass
Date: Thu Jan 14 1999
Hi Keith,
Thanks a million for this post. I had read there was frosted glass out
there that would work for ground glass use but none of the regular glass
suppliers had anything that was satisfactory (it was too coarse for ground
glass use). Armed with the knowledge that there was acid-etch glass on the
market I made a few calls, and on the second found a shop that carried the
material. Dropped by the shop this afternoon and for $19.15, including
labor, got 2 pieces for my 12X20 camera and another 2 pieces for a 11X14.
No question it is superior to the sand-blasted glass which I had been
using. I measured the illumination with the old sand-blasted piece and the
etched glass and there was about a full stop more light from the etched
glass.
By the way, while at the shop I was shown a product that you can use on
regular glass as a spray-on to give the frosted look. The person who
demonstrated it explained that it could be applied in very thin or heavy
coats, and when applied in thin coats it seemed to have about the same look
as the etched glass. This might be interesting to apply on clear plexi for
very large cameras.
Sandy King
rec.photo.equipment.large-format
From: dickburk@ix.netcom.com (Richard Knoppow)
[1] Re: Replacing Ground Glass
Date: Sat Feb 06 1999
wpflem@zebra.net wrote:
>2mm satin ground glass
>
> "Steve Shapiro" wrote:
>> Anyone know the 'technica;' jargon for the type of glass used for ground
>> glass?
>>
>> Frosted paper thin sound like a technical description?
>>
>> SS
I've had good luck with the ground glass sold by Edmund Scientific.
Its the right texture and thickness to replace the glass in most
view/press cameras. The price is about $20 US for a 8x10 sheet.
Smaller sizes do not save much. You will have to cut the corners off
yourself. I used a regular window glass cutter from the hardware
store. You can also get abrasives there for smoothing the edges and
corners.
---
Richard Knoppow
Los Angeles, Ca.
dickburk@ix.netcom.com
From: elliot@basis.demon.co.uk
Newsgroups: rec.photo.equipment.35mm
Subject: Re: how to clean finger prints on prism?
Date: Fri, 21 May 1999
I really doubt you have found fingerprints on the prism unless someone
has been REALLY careless, more likely the focussing screen, the bit of
plastic between the prism and the mirror. The mirror can be cleaned
with a blower and a _good_ lense cloth, but be really carefull cleaning
the focussing screen, they can scratch just by looking at them. If
there is dirt behind it, and it's removable, carefully flick the latch
that holds it in place and let it drop. don't take it out, get some
air-in-a-can and blow on it with this, being carefull not to catapult it
accoss the room with the force. Don't use a brush, you'll never get the
fluff off. Carefully click it back in place without touching the screen
itself, just the frame that holds it. cleaning fingerprints off the
screen could be a nightmare, try a microfibre lense cloth, pentax make a
good one. remember neither the mirror or the focussing screen/prism
affects picture outcome, so don't do anything too risky, it's just
cosmetic. If the focussing screen is gritted up/scratched/oily, you may
need to replace it. Just bought one today for a Nikon F90X (N90) and it
was 25 british pounds, whatever that is in US monopoly money. That is
if you can replace it. What camera do you have?
best of luck
Elliot.
> I found finger prints (with dirt) on the mirror and
> also on the prism(i guess). What is the best way
> to clean this?
>
> Thanks
> KG
From: Warren Jones warrenj@cybernet.co.nz
Newsgroups: rec.photo.equipment.large-format
Subject: Re: Ground glass/ **Alternative method**
Date: Tue, 08 Jun 1999
The best home-made groundglass by far that I've found is to use the peel
apart stick-on "Crystal Dust" vinyl. This stuff is used extensively by
the sign writing industry who computer cut it to apply frosted finish to
glass, plexiglass etc. Comes in rolls up to about a metre wide and sign
shops throw out larger pieces than your biggest groundglass because they
cannot reuse the off-cuts. Cut offcut slightly larger than your glass,
trim later.Simply clean glass, apply soapy water to surface requiring
"ground", peel apart and spread evenly. (hence soapy water)
Finer grain than I've been able to achieve with carborundum powder, sand
blast or even the nasty H.Flu. acid to etch.Cheap,safe,bright and quick.
Warren.
Sandy King wrote:
>csoles@rmi.net
> (Clyde Soles) wrote:
>
> > Waaaah! I broke the ground glass on my Korona 7x17" this weekend. What
> > are my options for replacing this? Are there any commercial sources or
> > will I be doing it myself?
>
> The least expensive alternative is to find a local glass store that stocks
> acid-etched glass and have then cut a piece (or two) to size for your
> camera. The type of etching varies somewhat among different manufacturers
> and some of it is too coarse for ground glass use so look at what is
> offered closely before having it cut.
>
> Another alternative is to buy a can of spray frosting and spray it on a
> clear sheet of glass cut to the size of your camera. ETC>>>>>>>>>> This
> product is generally sold at the kind of better glass stores that stocks
> acid-ethced glass.
>
> Sandy King
Date: Sun, 13 Jun 1999
From: Jon Grepstad gjon@online.no
Newsgroups: rec.photo.equipment.large-format
Subject: Re: Ground glass/ **Alternative method**
Jess4203 wrote:
> I remember a post back a good while on someone making ground glass by sanding
> glass with emery paper. I think he used 220 and/or 400 grit, and if I remember
> right, there was a discovery that 220 made for more sharpness than going finer.
> A search may turn up the post.
You will find information on how to grind your own glass by using # 600
carborundum here: http://home.sol.no/~gjon/lffaq.htm
Jon Grepstad
http://home.sol.no/~gjon
Date: Sun, 12 Sep 1999
From: billyb@browning.com (Billingham "Billy" Wellesley Browning )
Newsgroups: rec.photo.equipment.35mm
Subject: Re: What passes for "sharp"
>> a little obvious even on a small print. But it took me the greatest of
>> efforts to see the unsharpness on my very high quality ground glass. The
Even if all other factors were equal, groundglasses vary tremendously
and not in accordance with price or quality.
The more "coarse" the grain on a groundglass, the more obvious infocus
vs outfocus will be. The more fine the grain, the better the scene
will appear but the difference between infocus and outfocus will be
less apparent. In fact, the glass needn't be "ground" at all for the
"aerial image" to appear, but that image will not show
infocus/outfocus at ALL.
Different designers choose different degrees of coarseness as their
favorite, and most companies which offer changeable screens also offer
variety of coarseness.
Prisms themselves vary tremendously in size, type of glass, and
reflective coating (aluminum? silver?). My old OM-1 prisms are much
brighter and larger than my new Nikons'.
If different lenses could be viewed through the same body then
certainly they could be compared visually. It would be like comparing
telescopes. But it's tough to really remember the fine details of
each experience while switching lenses, so it's too bad we don't have
a method of making a permanent image of the view through each lens. If
we could do that, then we could compare the views after we tried all
lenses concerned.
Hmmmmmm..... oh, I know! Let's put film in the camera and take
PHOTOS through the lenses! Then we might compare them!
Bytheway, the Vivitar Series I lenses suffered from variable quality
control so there are poor ones and great ones in each style. The
great ones were frequently VERY great and much superior to most of the
runofthemill consumer-grade lenses sold today.
Just my 3 cents.
From: sanking@hubcap.clemson.edu (Sandy King)
Newsgroups: rec.photo.equipment.large-format
Subject: Re: Ground glass
Date: Mon, 07 Jun 1999
> Waaaah! I broke the ground glass on my Korona 7x17" this weekend. What
> are my options for replacing this? Are there any commercial sources or
> will I be doing it myself?
.....
The least expensive alternative is to find a local glass store that stocks
acid-etched glass and have then cut a piece (or two) to size for your
camera. The type of etching varies somewhat among different manufacturers
and some of it is too coarse for ground glass use so look at what is
offered closely before having it cut.
Another alternative is to buy a can of spray frosting and spray it on a
clear sheet of glass cut to the size of your camera. You can vary the
results with this product from a very fine eteching look to coarse
depending on how much you spray on. You could also spray this on clear
plexiglass as a back-up for the next time you break your ground glass.
This product is generally sold at the kind of better glass stores that
stocks acid-ethced glass.
Sandy King
From: "jjs" John@Staffprd.net
Newsgroups: rec.photo.equipment.large-format
Subject: Re: Source for Acid Etched Ground Glass
Date: Mon, 14 Aug 2000
Fujinon pdesmidt@fdldotnet.com wrote
> I'm looking for acid etched ground glass, and I'm not having much luck.
> I've tried internet searches. [...]
If it is simply acid etched glass for viewcameras you want, then ask and I
can send you the email address of a chap who does a lot of it. I paid $19
for two 8x10 pieces. They are just fine for my old view cameras, and
certainly better than the originals. Be sure to order the glass with the
corners cut, or cut them yourself. It's just the devil to do without that
feature.
Wait, surf eBay first. He often has auctions of his glass. Just search for
"acid" under photo-everything. Dinna Vorry - the sixties are over so you
won't get the wrong thing. Bid if you wish, but I am sure he will take
orders besides.
From Rollei Mailing List:
Date: Mon, 21 Aug 2000
From: JJMcF@aol.com
Subject: Re: [Rollei] Replacing the screen yourself?
you write:
I'm aware of the possible differences in the thickness of screens and was
thinking of calibrating the focus by using the screen of the plate
adapter.
Other solution I'm thinking of is to measure the thickness of the screens
and compensate the difference with shims. I was also hoping that the
replacement screens may have the same thickness as the original.
I've worked on a lot of old cameras with ground-glass screens and I'm not
sure I understand why there is any concern with the thickness of the
glass.
In almost all cases the ground-glass surface is on the inside, that is
toward the lens, and the image is formed there. As long as the ground
glass surface rests at the right distance from the lens it doesn't matter
greatly how thick the glass is.
JMcF
From Rollei Mailing List:
Date: Thu, 24 Aug 2000
From: Gene Johnson genej2@home.com
Subject: [Rollei] ground glass
Hello All,
I wasn't sure if I should put this out, but I saw something lately about
someone needing a groundglass. I have made 'temporary' screens that
work real well out of plexiglass and 400 grit wet and dry sandpaper.
Just cut the plastic out of the right thickness, peel the protector
sheet off of the side that will be roughed up, and rub in a circular
motion for about a minute while shifting your hand around on the plastic
all the time. Super easy. Works alot better than it has a right to. I
have a plastic supply house near my house and I have scraps in different
thicknesses. I bet though that if you had to have an exact thickness,
you could start with the next thicker size and just grind it down. I'll
be glad if somebody finds this useful for any reason, just don't start
with the heretic stuff. I've heard it before.
Gene Johnson
From Rollei Mailing List:
Date: Fri, 25 Aug 2000
From: Javier Perez japho@cunyvm.cuny.edu
Subject: Re: [Rollei] Sandpapering screens
Here are a few homemade screens ideas that work
Toilet paper
Rolling paper
sandblasted glass or plastic sheet
The paper can always be sandwiched between glass plates
Javier
[Ed. note: see followup posting...]
From Rollei Mailing List:
Date: Fri, 25 Aug 2000
From: pkkollas@gorge.net
Subject: Re: [Rollei] Sandpapering screens
Another approach, which i currently use on my 3.5F, is 3 strips of 3/4"
Scotch tape, placed on a clear plastic sheet the same size as the
original screen. It's quite a bit brighter in the center of the screen
than in the corners, but it sure is easy to see when good focus is
achieved. I used the plate glass back to achieve screen focus matching
taking lens focus. The term "collimate" has been used recently to
describe this matching of taking and viewing lens focus. Is this the
proper term?
paul
...
From Rollei Mailing List:
Date: Sat, 26 Aug 2000
From: Richard Knoppow dickburk@ix.netcom.com
Subject: Re: [Rollei] Sandpapering screens
you wrote:
>Another approach, which i currently use on my 3.5F, is 3 strips of 3/4"
>Scotch tape, placed on a clear plastic sheet the same size as the
>original screen. It's quite a bit brighter in the center of the screen
>than in the corners, but it sure is easy to see when good focus is
>achieved. I used the plate glass back to achieve screen focus matching
>taking lens focus. The term "collimate" has been used recently to
>describe this matching of taking and viewing lens focus. Is this the
>proper term?
>paul
Really not. Making lenses coincident is more accurate. Collimating is
using a collimator to adjust the infinity stop. A collimator is an
instrument which produces a beam of light which appears to come from
infinity. In its simplest form it is a corrected lens with a pin hole
source at its infinity focus. A simple collimator can be made from a view
camera provided the lens is fairly large. The process is "autocollimation"
which is useful for finding the infinity focus of a lens when a very
distant object is not available. You need a mirror and a small light
source.
The mirror is placed over the outside of the lens. A first surface
mirror is desirable but an ordinary shaving mirror will work. For a very
rough set up place the tip of a pencil flashlight against the ground glass
near, but not at, the center. An image of the flash will be projected back
through the lens to the ground glass. Focus it as sharply as possible. The
lens is now exactly at its infinity focus position. A light or mark on the
ground glass, seen through the lens will appear to come from infinity. It
is quite practical to check the infinity focus positions of cameras with a
makeshift collimator like this.
When setting up a twin lens camera like the Rollei two steps are
required. The first is to set the focus stop to infinity. On most Rollei
cameras this is done by slipping the focus knob on its shaft. The knob
itself contains the stop. The second step is getting the finder lens
coincident with the taking lens. This can be done at any distance and can
be done without setting the infinity stop first. The taking lens is set by
putting a piece of ground glass in the film gate so it rests against the
reference surface for the film. The lens is carefully focused on some
object. The finder lens is then adjusted so that it is also in exact
focus.
In most Rollei cameras the finder lens is mounted in a threaded barrel
which can be screwed in and out of its mounting. There is also some
arrangement for locking the lens in place once adjusted. The exact locking
arrangement varies with model.
Ideally, the coincidence ( and for that matter the infinity position)
should be calibrated using an autocollimator of the type which projects a
test subject into the front of the lens and allows viewing the projected
image inside the camera. This is done with a split prism and telescope.
This system allows focusing on actual film in the camera. Rolleis are
pretty good about film flatness so this is probably an unnecessary
refinement, nonetheless, its ideal if it can be done.
Rolleis are well designed and built so the adjustments are not hard to
make and are very stable once done.
----
Richard Knoppow
Los Angeles,Ca.
dickburk@ix.netcom.com
From Rollei Mailing List:
Date: Sun, 27 Aug 2000
From: pkkollas@gorge.net
Subject: Re: [Rollei] Sandpapering screens
It was an experiment, originally. The oeq is fine, but after some
discussion quite a few months back on this List about gg screens,
Fresnel screens, Bright screens, etc, and a comment by Bob Shell about
some people having difficulty in focusing with the brighter screens, i
decided to try the Scotch tape as a cheap experiment. I never replaced
it with the original. It's probably not what everybody would like, but
i'm not everybody. It seems that it is much easier to see when something
is dead-in-focus. I don't use zone focus often.
paul
Dave Huffman wrote:
> Why are you using this jury-rig rather than the oeq viewing
> screen/glass?
> Is it that much better than the oeq (which I am still using) -- or did
> you have a problem with the oeq view screen?
> Huff
Date: Thu, 28 Sep 2000
From: dickburk@ix.netcom.com (Richard Knoppow)
Newsgroups: rec.photo.equipment.large-format
Subject: Re: How to Clean an Older Groundglass?
"Mark Westling" mwestling@earthlink.net wrote:
>I'm refurbishing an older Kodak 2-D 5x7 camera; its groundglass has dirt, a
>variety of smudges, and what looks like a bit of gaffers tape adhesive stuck
>to it.
>
>Anyone know the best cleaner/solvent to use to clean it thoroughly?
>
>Thanks in advance!
>
>Best regards,
>
>Mark Westling
For just dirt either plain dishwashing detergent or Bon-Ami works.
Tape residue may be tough. Try Acetone or strong Isopropyl alcohol on
it. There is also a good cleaner available at hardware stores called
Goof-Off that seems pretty harmless. Of course, take the GG out of the
camera before using solvents on it. There isn't really much you can do
that will hurt the glass other than dropping it.
I've found a couple of times old GG was so coated with oily grime
that it seemed to be coarser and dimmer than it really was. Cleaning
them made an astonishing difference.
---
Richard Knoppow
Los Angeles, Ca.
dickburk@ix.netcom.com
Date: Thu, 28 Sep 2000
From: "Nicholas O. Lindan" nolindan@ix.netcom.com
Newsgroups: rec.photo.equipment.large-format
Subject: Re: How to Clean an Older Groundglass?
Richard Knoppow wrote:
> There is also a good cleaner available at hardware stores called
> Goof-Off that seems pretty harmless.
There are a couple of these 'Goo' cleaners.
Some are made from Xylene. These work by leaving the goo where it is and
dissolving what the goo was stuck to - that's a joke, but not much of one.
Xylene is a pretty universal solvent and so it will dissolve most paints,
inks and plastics. Xylene is kind poisonous. Most folks puke before
the concentration gets too high so there haven't been many cases of injury
from the stuff. But it is foul. I get a headache if I breath too much -
xylene, that is.
The better products are made from orange oil (from oranges, like you eat).
This stuff is safe for just about everything but check first! It will
dissolve polystyrene and plain lo styrene - like is used in picnic
utensils and plastic toy models - remember how a plastic spoon/knife
gets gooey when it is used to peal an orange.
Goof Off is made from xylene and methyl & ethyl alcohol.
Goo Gone is made from citrus oil naphtha (naphtha is lighter fluid).
Goo Off is ridiculously expensive if you look at the price of a quart of
xylene at the hardware store - $3.98 or so. Probably the mark up on Goo
Gone is just as bad, but I don't know the going rate for citrus oil.
In my experience Goo Gone has always worked well. Goo Off mostly doesn't
work.
As others have posted WD-40 works quite well, won't harm any plastics
and most folks have a can. Let WD-40 soak into the glue for a half
hour or so before cleaning the stuff off. It make take two applications.
--
Nicholas O. Lindan, Cleveland, Ohio nolindan@ix.netcom.com
Date: Tue, 3 Oct 2000
From: Mitch Winkle mwinkle@jonatas.com
To: medium-format@egroups.com
Subject: [medium-format] Brightening your own viewfinder screen
Hey everyone.
I have seen articles and posts on photo.net, in the LF section, about
making adjustments to the ground glass to make it more friendly to focus
with. One in particular was carefully wiping on a layer of silicone spray
(on the ground side) which is reported to increase light transmission.
Has anyone tried this with a MF viewscreen? Curious to see if it would
work. The old Yashicamat, even with a new mirror, is kind of dark in some
cases with a f/3.2 viewing lens.
Mitch Winkle
mwinkle@jonatas.com
AC4IY
Date: Sat, 07 Oct 2000
From: dickburk@ix.netcom.com (Richard Knoppow)
Newsgroups: rec.photo.equipment.large-format
Subject: Re: Ground Glass Replacement
JIB jbuf@ix.netcom.com wrote:
>I sell ground glass 8x10 sheets shipped in the US for $15 each
>Thanks
>John
>
>Richard Knoppow wrote:
>
>> Jon Grepstad gjon@online.no wrote:
I didn't know and wish I had. Thats about $5 a sheet cheaper than
other sources. Do you have larger sheets? I am looking for a
replacement for a Morse contact printer, around 11" x 11"
---
Richard Knoppow
Los Angeles, Ca.
dickburk@ix.netcom.com
Date: Wed, 04 Oct 2000
From: Ian Dodd iandodd@mediaone.net
Newsgroups: rec.photo.equipment.large-format
Subject: Re: Ground Glass Replacement
Mark,
Have you considered making your own? It's quite simple and very
inexpensive.
Check out this link to learn how:
http://gamma.nic.fi/~mikoneka/materials.html#groundglass
Ian Dodd
Mark wrote:
> Many thanks once again to all who helped advise me on cleaning the
> groundglass on my "new" Kodak 2-D 5x7 I just purchased on EBay. After
> getting most of the adhesive off (not all), I'd like to look into purchasing
> a new groundglass for the camera. Any suggestions on where to buy one?
>
> Thanks,
>
> Mark
rec.photo.equipment.large-format
From: PHOTO-TECH photo-tech@home.com
[1] Re: Making Ground Glass
Date: Tue Oct 31 2000
I suggest looking into standard non-glare framing
glass. It's worked for me for the last 5 years and $10 gave
me a 8X10 piece which was cut for free into 4 - 4X5's.
Regards,
John S. Douglas
rec.photo.equipment.large-format
From: PHOTO-TECH photo-tech@home.com
[1] Re: Making Ground Glass
Date: Wed Nov 01
sanking@clemson.edu wrote:
>John,
>
>I did not understand the meaning of your response. Are you suggesting
>uses of the non-glare framing glass as a ground glass without further
>elaboration? Or was this a suggestion for a base for etching?
>
>Sandy King
Hi Sandy,
Non-glare glass is already etched. I think it's
actually glass beaded as the texture is pretty fine. It's
worked pretty well for me since I broke the GG in my Zone
VI.
Regards,
John S. Douglas
Photographer Web Master Darkroom Wizard
rec.photo.equipment.large-format
From: Marv Soloff msoloff@worldnet.att.net
[1] Re: Making Ground Glass
Date: Tue Oct 31
Roy:
Two good methods for making ground glass - use a sandblaster, or if you
are like me without any sandblast equipment, go to your local auto parts
emporium and buy a tube of valve grinding compound. Squirt it between
two panes of cut glass, move the top pane around evenly until you get
the desired "ground" effect, wash off and voila - ground glass! Total
time is about 10 minutes. Cost for the valve grinding compound is about
$2.50. One tube of valve grinding compound will make enough ground
glass to last you a lifetime. Of course your mileage may vary. Be
careful not to cut yourself on the sharp edges. Wash thorougly after
use. Etc.
Regards,
Marv
Date: Mon, 30 Oct 2000
From: "Peter De Smidt" pdesmidt@fdldotnet.com
Newsgroups: rec.photo.equipment.large-format
Subject: Re: Making Ground Glass
Pam Niedermayer pam_pine@cape.com wrote
> Do you know anything about acid etching? Are there advantages, such as a
> brighter view, to acid/chemical etching vs mechanical?
Hi,
Acid etching can give a ground glass with very fine grain, although not as
fine a grain as can be gotten with a wax screen (I'm blanking on the
name). I prefer acid etched glass to any of the screens made with
mechanical means that I've seen. I believe that Sinar, Linhof, Arca Swiss
and Toyo, among others. use acid etched glass. The problem is getting the
glass. None of the glass suppliers around here know where to get it.
Sandy King has sent me a name of a place where he bought some, but I
haven't had the time to check it out yet.
You can acid etch your own glass, but I *strongly* recommend not doing so.
First, the acid is really, *really* nasty stuff. Second, it's almost
impossible to get an even etch. I tried about 15 ways, including fuming,
and while I could get usable glass, it was noticeably uneven. I took my
results to several 'art' glass places, and they said, "Wow, that's better
than we can do." It wasn't good enough in my book.
According to Richard Knoppow, a reliable source if every there was one,
Edmund Scientific makes some very nice ground glass. I just bought some
from Steven Shuart. It is a little thick, and it has visible bands, but
it's ok.
Regards,
Peter
Date: Sat, 04 Nov 2000
From: "Ralph W. Lambrecht" lambrecht@btinternet.com
Newsgroups: rec.photo.equipment.large-format
Subject: Re: Ground Glass before or after Fresnel-Lens
Actually it works both ways.
Linhof has a preference for putting the fresnel behind the ground glass
(OGF) where others like Toyo like to have it in front of the ground
glass (OFG). The benefit of OGF is that there is no focal shift required
and the system can be used with or without fresnel. The disadvantage is
that the fresnel is not protected and scratches easy. The OFG system
needs a focal shift (shimming of the ground glass).
Since you spoke about a Linhof, I assume that the ground glass is
installed first and then covered by the fresnel.
Ralph W. Lambrecht
O = lens
F = fresnel
G = ground glass
From: jess4203@aol.com (Jess4203)
Newsgroups: rec.photo.equipment.large-format
Date: 20 Nov 2000
Subject: Re: Replacement Ground Glass
Mr. (Ms.?) Hollander:
In a recent thread, someone advised me to make my own by getting two
pieces of glass, one the right size and one scrap, and put a teaspoon of
valve grinding compound between them. Rubbing them together about ten
minutes should do it.
I am investigating procuring some of the acid etch paste (very weak HFl) I
used to use for stained glass etching. I think it may produce an even
enough etch if you prefer an acid etched GG.
I couldn't see paying $10 plus shipping for the GG when I got a piece of
window glass from the thrift store for $1 and can borrow a cutter. The
valve grinding compound was $2.80. Your local hardware might cut the
glass for you to fit.
To each his own.
HTH,
Roy
Date: Tue, 12 Dec 2000
From: "G.Penate" penate@home.com
Newsgroups: rec.photo.equipment.large-format
Subject: Re: How to evaluate lens sharpness
richardhelzer@my-deja.com wrote
> No Pam , I meant to suggest temporarily attach a piece of clear glass
> to the back instead of the ground glass . This doesnt really give you
> something to focus on but supplies a firm support for a loupe that can
> then be focused on the aerial image. One thing I did do was mark in
> pencil a small cross , this can be helpful when focusing, over this
> cross I attached a small piece of clear packaging tape . This gives me
> a center spot of almost clear glass for use in critical focusing. The
> tape is so far the best thing I've found so far and is removable but
> some sort of clear shellac or something else may be better . Hope this
> clarifies my post sorry for the confusion.
Substituting the GG by a piece of clear glass is something I do very
often, I do zoneplate photography and the aerial image is clearer,
brighter and it shows exactly what the film will be seeing.
Now, why would you stick a piece of clear tape to the clear glass, when
you make a pencil mark and focus on it, you are focusing exactly at the
same distance (from the lens) the GG would be located and if the GG is
properly aligned, at the same distance the film will be. Do you use that
piece of clear tape on the clear glass to sort of diffuse the light as a
GG does, if so, you are no longer focusing on the aerial image.
Could you explain?
Thanks,
Guillermo
Date: Tue, 12 Dec 2000
From: richardhelzer@my-deja.com
Newsgroups: rec.photo.equipment.large-format
Subject: Re: How to evaluate lens sharpness
> Now, why would you stick a piece of clear tape to the clear glass,
Its amazing how poorly I can express myself :) . Again I apologize for
the confusion . The clear tape is added to my regular ground glass to
provide a small area of clear glass . This as you know brightens the
image and doesnt obscure the fine detail. The pencil mark is probably
of little value but is supposed to help in focusing an arial image.
after you have focused the image , if you move your head from side to
side the pencil mark is not supposed to shift if you are focused
exactly on the chosen plane of focus. I hope this clarifies my previous
post.
Sincerely Richard Helzer
From: "Christopher M Perez" christopher.m.perez@tek.com
Newsgroups: rec.photo.equipment.large-format
Date: Wed, 29 Nov 2000
Subject: A tale of ground glass alignment
A year ago I purchased an inexpensive Linhof 4x5 Super TechIII (later
model with Graflock back) and took it on two trips. I wasn't exactly
thrilled with the results. Images failed to 'pop' off the paper. I felt
a longing for the return of my 8x10 Deardorff and contact prints.
Then a month ago I tested a stack of new lenses I'd recently purchased.
The results were horrid.
At a loss to explain the situation I dusted the oil and grime off a dial
indicator previously used to tune Yamaha RD400 two-stroke motorcycles back
when I terrorized the countryside. The Linhof removable back has a nicely
machined ridge which could be used to rest a measuring setup against. I
then made sure I was measuring in the same spot in each of the four
corners and center of the holders and ground glass.
I found that the ground glass was 1.11mm's backset from modern Lisco film
holders loaded with a processed neg (to include film thickness in the
measurement). Eureka. Problem uncovered.
Taking a suitable shim material (very heavy paper/lite cardboard packing
material :-) I created shims and reset the groundglass plane to match the
holder/film measurements.
Last night I went back out to my USAF resolution chart and retested a Fuji
135 W/EBC f/5.6 and a Rodenstock 150 APO Sironar(W) f/5.6. The results
confirmed the new setup as being accurate.
(http://www.hevanet.com/cperez/testing.html)
Interesting side notes: I have a family of newer and older film holders of
several different varieties. The new holders allow film to lay nice and
flat against holder base. Some of the older holders hold the film tight
against the rails and 'bow' the center of the film. Measuring the film in
these two holder types showed me that the focusing plane to be identical
in practice. Amazing.
Additionally, in my family of film holders I have a 0.11mm (0.004 inch)
focus plane variation. This appears to be well within tolerance (assuming
a 0.016 inch tolerance).
Needless to say, I'm thrilled at the improvement made in my overall 4x5
system. This is the very first time I've noticed/encounted this kind of
problem. So if your LF images just don't seem 'right', and you're using
older equipment, maybe the groundglass is misaligned?
Thanx for listening.
- Chris
From: LoveThePenguin dpcwilbur@my-deja.com
Newsgroups: rec.photo.equipment.large-format
Date: Wed, 29 Nov 2000
Subject: Re: A tale of ground glass alignment
I've had to fuss a little with the ground glass, but that doesn't
affect that "jumping off the paper" that's so important in a good
image.
My particular fuss has been with film holders. Unless one spends a
bundle on a vacuum-backed holder, there's so much bowing in 4x5 that
a Mamiya RB image will be technically better in may respects.
(like consistency in DOF -- and it doesn't take much looseness to
produce a noticable difference)
What I need is this: A 4x5 back that mechanically grips the medium,
and provides a small pull. Perhaps as simple as a soft sponge edge
grabs by the tiniest amount but provides a bit of tension for a
flatter film plane.
Does something like this exist?
Collin
...
Date: Wed, 29 Nov 2000
From: "Christopher M Perez" christopher.m.perez@tek.com
Newsgroups: rec.photo.equipment.large-format
Subject: Re: A tale of ground glass alignment
LoveThePenguin wrote in message <903h3f$9mc$1@nnrp1.deja.com>...
...
>My particular fuss has been with film holders. Unless one spends a
>bundle on a vacuum-backed holder, there's so much bowing in 4x5 that
>a Mamiya RB image will be technically better in may respects.
>(like consistency in DOF -- and it doesn't take much looseness to
>produce a noticable difference)...
I found the difference between all my holders to be 0.11mm (0.0043
inches!). That's not bad at all. I have 120 cameras that bow more than
this! So I'd say buy a stack of identical 4x5 film holders (newer the
better), measure them in your camera back and check their alignment.
Choose the most consistant, use them, and sell the rest.
Dial indicators are wonderful things... :-)
- Chris
From: dickburk@ix.netcom.com (Richard Knoppow)
Newsgroups: rec.photo.equipment.large-format
Date: Thu, 30 Nov 2000
Subject: Re: A tale of ground glass alignment
...
I wonder where this error came from. 1.1mm is too thin to be
accounted for by a field lens. If the ground glass reference surface
is the smooth surface rather than the ground surface I suppose its
possible that the back was intended for a thicker sheet of glass.
Curious.
I had a sort of similar problem with my first Speed Graphic, an
early Anniversary model. I thought I was getting sharp pictures at
first, then found they just were not very good. I traded the original
lens, a Jena Tessar, for a Kodak Ektar. While doing this, and after
struggling with the rangefinder, which seemed to be completely
unstable, I discovered the ground glass was not being held in place by
the side clamps. Probably it was not the original glass is was just
slightly too narrow. In any case, after I fastened it so that it
wasn't moving around, the camera became very sharp. The original
Tessar is a very good lens, though the Ektar is a bit sharper, the
problem was from the ground glass not only being in the wrong plane
but moving around.
UGH!
I've tested all my holders using a depth gauge. The Riteway brand in
4x5 and 5x7 all seem to be right on the nose. Older Graflex wooden
holders vary around although most are OK.
8x10 is a bit different. Old holders seem to very often have major
errors, perhaps from warping or from the center septum having moved.
At some point I will take one apart to see if it can be fixed.
Kodak (Graflex) holders seem to be the best of the older ones, Agfa
varies around, I have several good ones. The modern holders are all
right on the nose, but I have a box of old holders which are too far
off to be usable. My experience is that really old holders are not
worth buying, however cheap they may be, unless you can measure them
before hand.
---
Richard Knoppow
Los Angeles, Ca.
dickburk@ix.netcom.com
From: dickburk@ix.netcom.com (Richard Knoppow)
Newsgroups:
rec.photo.equipment.large-format
Date: Thu, 30 Nov 2000
Subject:
Re: Groundglass with cut corners
"Aaron Ng" ngaaron@singnet.com.sg wrote:
>Hi,
>All groundglasses I have seen has cut corners that gets into the way of
>viewing quite often. I usually have to slide to both sides to make sure that
>the edges are alright. Has anyone here found a way to use a completely uncut
>groundglass (other than drilling small holes near the corners)?
>Thanks,
>Aaron
The cut corners are not to let air in or out, they are to allow
seeing the lens from the corners to check for vignetting. Many cameras
have full ground glass, the Calumet C-1 and cameras with Graflok backs
among them.
Full corners may not fit into some older cameras. My Agfa/Ansco
cameras have raised areas at the corners of the ground glass champfer
which require the edges to be cut out, other cameras don't.
Most backs have enough air leaks to permit focusing or folding the
bellows without needing cut corners for that purpose.
---
Richard Knoppow
Los Angeles, Ca.
dickburk@ix.netcom.com
Date: Thu, 19 Apr 2001
From: "Brian Ellis" bellis60@earthlink.net
Newsgroups: rec.photo.equipment.large-format
Subject: Re: Caring for LF equipment
If the ground glass is gridded, be careful about cleaning the ground side
with anything. I learned the hard way that cleaning that side with Windex
can result in the grid lines disappearing.
...
From Camera Makers Mailing List:
From: "Daniel Rhoades" danielrhoades@msn.com
Date: Mon, 28 May 2001
Subject: Re: [Cameramakers] Scanner mods for enlarger
One site that talks about making your own ground glass is:
[Ed. note: page was at:
http://rhoadescameras.bizland.com/Camera%20Creation/Ground%20Glass/ground=_glass.htm
not found in link check 2/2003]
Dan Rhoades
www.rhoadescameras.bizland.com
From Rollei Mailing list
Date: Sat, 15 Sep 2001
From: Lloyd Schultz Lschultz2@nconnect.net
Subject: Re: [Rollei] Ground glass crop marks
I use a charting tape called Zip tape. I is almost like pin striping
tape, but in the days before computer graphics and Power Point, was used
to make charts,etc. Comes 1/8, 1/16th and 1/32nd widths - go for the
narrowest.
Lloyd
Lschultz2@nconnect.net
From Rollei Mailing List:
Date: Sat, 15 Sep 2001
From: Gerald Lehrer jerryleh@pacbell.net
Subject: Re: [Rollei] Ground glass crop marks
Lloyd
I've found that if you leave the Zip-Tape on
any plastic for more than a day or so, it will
permanently bond to the plastic focusing screen.
That's why I use the tape on a seperate plastic
insert on my H'blad. I once ruined a Rolleiflex
screen by applying the tape directly to it.
Jerry
From Rollei Mailing List
Date: Sat, 15 Sep 2001
From: Bob Shell bob@bobshell.com
Subject: Re: [Rollei] Ground glass crop marks
At the same store where you buy the tape you can usually also buy sheets
of transparent acetate and/or Mylar. Make your marks on a piece of this
that fits down snugly on top of the screen.
Bob
From: dickburk@ix.netcom.com (Richard Knoppow)
Newsgroups: rec.photo.equipment.large-format
Subject: Re: Help finding 2mm glass
Date: Sun, 31 Mar 2002
"gk" eok3@earthlink.net wrote:
>Hi,
>
>I busted the GG on my Century Graphic and am trying to do a replacement
>myself. I know of the guy in Pa. that makes them, but I already bought the
>supplies to do the grinding.
>
>The one element I can't find is the 2mm glass. Does anyone know of an online
>(or other) place to get this stuff? I live in Orange county Ca., and have
>tried literally dozens of specialty glass shops, and none of them have it.
>Every place I go says that this glass is way too much of a special item, and
>would need to be ordered by the truckloads!
>
>After searching Google on this matter, many folks seemed to have no problems
>finding it. Please forward any info you can. I am getting frustrated driving
>to places to find out that their 2mm is actually 2.5, or 3mm.
>
>I have some other cameras that I'd like to replace the glass on as well, so
>I'd need a little more than the 2 1'4 x 3 1'4 size.
>
>Any help would be greatly appreciated.
>
>gk
Edmund Scientific, or maybe its Edmund Optics now, sells the right
kind of ground glass, fine grained and the right thickness. I haven't
checked prices recently but it was about $20 US for an 8x10 sheet when
I last bought some. Smaller sheets are nearly as expensive because you
are paying for someone to cut them.
Since the ground surface is located by a reference surface the
thickness of the glass is usually not too critical, provided it will
fit.
I am at the moment looking at a sheet of 2mm glass I got at Home
Depot a couple of weeks ago. Its 11x14 for an old contact printing
frame. Cost about $2 US I think.
---
Richard Knoppow
Los Angeles, CA, USA.
dickburk@ix.netcom.com
From: dickburk@ix.netcom.com (Richard Knoppow)
Newsgroups: rec.photo.equipment.large-format
Subject: Re: Better ground glass for my B&J;?
Date: Tue, 30 Jul 2002
fotocord fotocord@yahoo.com wrote:
>Well I got my old 5X7 B&J; grover "restoration" finished last night and went
>out to burn some film in it. I'm not sure if this is the original ground
>glass but it's AWFUL!!! It's very coursely gound and was real hard to tell
>when something was in focus or not. I don't really care if a different one
>is brighter or dimmer but I need something that I can at least tell when
>things are in focus! This one has a crack in the corner so I knew I'd need
>to replace it but now I know I do! Anyone know who has something better for
>a small outlay of cash? I saw calumet has a 5X7 glass for $40 with rulled
>lines. What about acid etched ones, are those good?
>
>BTW those 5X7 negs blew me away! Makes me think I might want to find an
>8X10...
>--
>
> Stacey
First, make sure the glass is clean. When ground glass gets a
coating of oily residue on the gound side it can make it look coarse
and dim. Use dishwashing detergent.
It cleaning doesn't have any effect Try Edmund Optics, last I looked
5x7 sheets of fine grain GG were around $15. You can get GG from other
sources too but I've used the Edmund stuff and its the right grain and
thickness.
I don't know if B&J; used ruled GG. Its easy enough to rule your own.
The simplest method is to use a pencil on the ground side. For more
permanent markings use drafting tape on the glass side.
---
Richard Knoppow
Los Angeles, CA, USA.
dickburk@ix.netcom.com
From: Gary Frost gary.frost@nospam.com
Newsgroups: rec.photo.equipment.large-format
Subject: Re: Better ground glass for my B&J;?
Date: Tue, 30 Jul 2002
I have a B&J; 'Saturn 75' 5X7 and found the GG too course for my taste.
You can make your own with Carborundum lapidary powder, water, and
an extra glass for a working surface. Use a #400-600 grit. I use #500
and find I wouldn't want it any finer. My guess is the B&J; was ground
with around #200. It is easier to get a nice GG surface finish than it
is to get nice clean cuts for the corners. Sand any sharp edges to
avoid chips and cuts.
Make sure the surfaces are clean before you do the grinding.
Date: Tue, 30 Jul 2002
From: "Jeff Novick" jhnovick@pacbell.net
Newsgroups: rec.photo.equipment.large-format
Subject: Re: Better ground glass for my B&J;?
Gary,
This is a link to a guy who sells very bright, thin, ground glass for most
cameras. I have not used his product nor know anything about it, but, he
guarantees satisfaction. You may want to go that route rather than the DIY
path. The link is to an ebay listing but you can get to his site from there.
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item;=13560
Jeff
[Ed. note: invalid item number per EBAY (chopped when copied into above?); here as a
reminder to check EBAY for possible vendors of odd-ball sized ground glass...]
From: dickburk@ix.netcom.com (Richard Knoppow)
Newsgroups: rec.photo.equipment.large-format
Subject: Re: where do you buy ground glass?
Date: Mon, 19 Aug 2002
eromney eromney@zianet.com wrote:
>where do you buy ground glass? I need a 5 x 5 inch piece for a Super D
>Graflex and a 4 x 5 piece for another camera.
>
I've gotten ground glass from Edmund Scientific a few times. They
recently split up the company, the gg may now be part of Edmund
Optics. A Google search will get you the web addresses.
Their ground glass is fine grain and the right thickness. Its most
ecomomical to order it in 8x10 sheets and cut it youself. The price of
smaller pieces includes some labor charge for cutting so is not much
less than the larger sheets. As near as I can tell the quality of the
glass is the same as that used by Graflex.
On another post, I can't help with shutter cloth, I've been trying
to find a source of rubberized or plastic coated cloth myself for both
focal plane shutters and for building bellows. Most fabric stores
have no idea what you are talking about. I've found some frustratingly
close material in stores selling upholstering materials, but it was
too stretchy. Since cloth FP shutters are still made and certainly
bellows are still made, someone must be making the right cloth.
---
Richard Knoppow
Los Angeles, CA, USA.
dickburk@ix.netcom.com
From: "gk" eok3@hotmail.com
Newsgroups: rec.photo.equipment.large-format
Subject: Re: where do you buy ground glass?
Date: Tue, 20 Aug 2002
"fotocord" fotocord@yahoo.com wrote...
> eromney wrote:
>
> > where do you buy ground glass? I need a 5 x 5 inch piece for a Super D
> > Graflex and a 4 x 5 piece for another camera.
>
> I made my last piece for my 5x7 and it works pretty good. Do a search and
> you'll find directions using carbonium (sp?) powder (400 grit was was I
> used).
> --
>
> Stacey
I do the same now. It's called Carborundum, and you get it at a rock/gem
polishing store. Believe it or not, they do exist!
Basically, you get two pieces of glass, sandwich them together with some of
the carborundum (adding water to it to make a paste) between them. Then just
rub the two surfaces of glass together for a couple of minutes. You can
rinse off the mess and check for consistency. A 4x5 takes me about four
minutes.
Good luck
[Ed. note: possible source of custom cut ground glass, caveat emptor!]
From: "John Buford" Jbuf@ix.netcom.com>
Newsgroups:rec.photo.marketplace.large-format,rec.photo.marketplace
Subject: Ground glass blow out sale
Date: Mon, 9 Sep 2002
4x5 in. 1/16 in thick acid etched high quality. ground glass. $20.00
including insured delivery anywhere in the US. 2 sheets $32.00
4 1/2 X 6 1/2 in 1/8 inch thick acid etched, high quality, ground
glass. $12.00 for one sheet including insured shipping anywhere in the
US, 2 is $17.00. This is a great size for experimenters and any one
who would like to cut there own glass for an project. I built a nice
little light box, for darkroom use, with a 3 watt bulb.
5x7 in 1/8 in thick acid etched, high quality, ground glass, $15.00
for one sheet including insured shipping anywhere or 2 sheets for
$22.00.
These are all first quality new old stock ground glass I can and will do
custom sizes, (up to 48 X 96 inches in 1/8 or 1/4 inch) . Please
email me with your needs and I will get back to you. I trade on Ebay as
M3ds, I have over 1300 positive feedback's. I accept credit cards and
electronic checks through accept Paypal and Billpoint, Both of these
are great services, they are safe and free to you. Using these also
expedites shipment to you. if you have any questions or concerns
please feel free to write
Thanks
John
From camera makers mailing list:
Date: Tue, 22 Oct 2002
From: Marv Soloff msoloff@worldnet.att.net
To: cameramakers@rosebud.opusis.com
Subject: Re: [Cameramakers] Ground glass
Valve grinding compound works very well in making ground glass. And,
making it yourself, you can make it any size you want, when you want. If
you can find it, 400 grit grinding compound (for telescope making) also
works well.
Regards,
Marv
> > Also, I am having trouble finding a suplier for the abrasives to make
> > the ground glass. I have found a few on the internet, but they have a
> > minimum order for $25 or more. Since the abrasive is only about $3-$4
> > per pound I hate to pay this much since a pound would be more than
> > enough for my needs.
>
> Some ideas ... most hardware stores have grinding compounds and/or can
> order it. How about an automotive store? I'd guess that valve grinding
> compound would work?
>
> - Wayde
> (wallen@lug.boulder.co.us)
Date: Wed, 23 Oct 2002
From: jahn baker bakerjg@wildapache.net
To: cameramakers@rosebud.opusis.com
Subject: Re: [Cameramakers] Ground glass
If you can find a stained glass supply house, they sell an acid for
etching glass that does the trick very nicely. The biggest trick with it
is spreading it evenly on the glass - a glass rod worked well for 4x5
size. The acid etched glass is a little brighter than the abrasive
ground, but a little trickier to pull focus. A good 4 or 6 power loop
really helps.
Jahn
From camera makers mailing list:
From: "John Cremati" johnjohnc@core.com
Subject: Re: [Cameramakers] ground glass grinding
Date: Sun, 2 Mar 2003
I had just made a experimental ground glass panel for a 8x10 .... I
had acid etched it first and then I "lightly" sandblasted it with 240
grit... or I should say faintly as it was just enough to randomly etch
the surface using very low air pressure. The appearance if it had not been
acid etched first would be that you could see thru the glass as looking
thru a very light fog.... I was very pleased with the result... The acid
gives it a very mat finish and the sandblast effect evidently catches more
light and allows for a brighter screen with a more even distribution of
light through out the screen . Be careful not to over do the sandblast as
you will wipe out the acid work and acid etch the screen several times to
get a even etching. .. The combination of the two gives a very pleasing
screen..
If I was to do it over again I would try to acid etch the screen
using a liquid etch and not the paste to give a more even etch and would
lightly sandblast using a 320 grit at a higher pressure..
If your just going to sit there and grind away using a plate of glass
or metal to apply the grit to I would use a 240 to 320 grit..Start with the
240 and then proceed to the 320 if needed. 320 will give you a very fine
etching.. ( 600 grit you are beginning to get into a prepolish phase in
glass polishing..) ...
> I save all the digests, but that makes it harder to retrieve info too -
> takes a long time to search -
>
> If I use Silicon Carbide to make ground glass, what grade or grades should I use?
>
> Thanks
>
> Murray
From: "Brian Ellis" bellis60@earthlink.net
Newsgroups: rec.photo.equipment.large-format
Subject: Re: Making your own ground glass
Date: Fri, 02 May 2003
There's an article on making your own ground glass in the current issue of
"Photo Techniques" magazine.
Images and Photography Information www.ellisgalleries.com
"David Nebenzahl" nobody@but.us.chickens wrote
> kabkos spake thus:
>
> > I have had good luck using an adhesive backed product sold at sign/billboard
> > shops called "StarDust". I apply it on an appropriately sized piece of
> > glass and install it with the dull side towards the lens. I have found it
> > is much brighter than a standard ground glass.
> >
> > You can also make your own ground glass using the finest silicon grit that
> > you can find mixed with oil. The grit is available at machine shops in
> > various grades. Apply the grit and oil to the precut piece of glass and rub
> > it against another piece of glass. Takes about 20 minutes for a 4x5 ground
> > glass. This is what I used to do prior to finding the "StarDust" material.
>
> I take it you're talking about something finer than silicon carbide valve
> grinding compound, right? I've used this to make small pieces of ground glass;
> it works, but is pretty coarse (I'm guessing somewhere around 80-100 grit?).
> So what specific grits do you recommend?
>
> By the way, I think water would work just as well as oil for this application.
> (The valve grinding compounds are water-based.)
>
> > "Jim Waggener" jimw@visi.net wrote
> >> I thought I may brighten the image with new GG...wrong!
> >> The old glass on my Kodak Master View is *much* finer than the new. Focusing
> >> is measurably easier with the old glass. Another waste of money buying a new one.
> --
> As for lean, these grossly, grossly, grossly overweight all-American
> lard-ass behemoths come in at 155% of the mass (293,500 lbs vs 86 t) and
> 42% of the power (3600 hp vs 6.4 MW) of your typical contemporary
> Euro-weenie locomotve. A good thing extreme measures are being taken
> to keep oil cheap.
>
> - Richard Mlynarik
From: tls@panix.com (Thor Lancelot Simon)
Newsgroups: rec.photo.equipment.large-format
Subject: Re: Ground glass..replacements are COARSE!
Date: 1 May 2003
Jim Waggener jimw@visi.net wrote:
>I thought I may brighten the image with new GG...wrong!
>The old glass on my Kodak Master View is *much* finer than the new. Focusing
>is measurably easier with the old glass. Another waste of money buying a new
>one.
The old glass was probably acid-etched; the new glass is probably actually
real ground glass. Acid-etched glass should not be too hard to find, or
you could consider one of the various types of "bright screens" that are
around (I am pretty happy with the Beattie Intenscreen on my Wisner).
--
Thor Lancelot Simon tls@rek.tjls.com
[Ed. note: for info only, not recommended process;
buying ground glass is much cheaper and safer!!]
From: "Richard Knoppow" dickburk@ix.netcom.com
Newsgroups: rec.photo.equipment.large-format
Subject: Re: Ground glass..replacements are COARSE!
Date: Wed, 14 May 2003
"Peter De Smidt" pdesmidt@dotnet.com wrote
>
> > >
> > Can you use that liquid glass etching stuff the stained-glass people use?
> > It is some kind of acid that gives a fine grain. Might try that.
> >
>
> Yes, you can, but it is very hard to get an "even" ground glass effect. I
> know, as I've tried numerous techniques. Plus, the acid is supposed to be
> quite nasty. I didn't test this latter claim.
>
> -Peter
It may be a solution of Sodium or Potassium Fluoride.
Hydrofluoric acid can be used to etch glass but its
extremely hazardous. It causes severe burns which are
resistant to healing.
An old book _Photographic Facts and Formulas_ 1940
edition, suggests using the following for fine ground glass.
I've not tried this and can't vouch for it.
Sodium or Potassium Fluoride 4 grams
Gelatin 4 grams
water 1 liter
Coat on the glass and allow to set and dry. The immerse in a
6% solution of Hydrochloric acid for 30 to 60 seconds. Dry
without washing. Dissolve the gelatin off with water.
The hydrochloric acid and fluoride form hydrofluoric acid.
Be _very_ careful with the hydrochloric acid.
---
Richard Knoppow
Los Angeles, CA, USA
dickburk@ix.netcom.com
From: "Richard Knoppow" dickburk@ix.netcom.com
Newsgroups: rec.photo.equipment.large-format
Subject: Re: GG cut corners?
Date: Fri, 25 Apr 2003
"Stacey" fotocord@yahoo.com wrote
> Never used a ground glass with cut corners, my newest toy has them. What
> exactly am I looking for/at to see if I've run out of lens?
> Stacey
The cut corners are so that you can look back at the lens.
You can see when the full aperture is visible and not partly
vignetted by the lens mount, or when the entire aperture is
obscured, at which point the lens vignettes. This is useful
when using camera movements.
You will occasionally see the explanation that the corners
are air leaks for the bellows, but the camera back doesn't
seal anyway, they are there for the above reason.
---
Richard Knoppow
Los Angeles, CA, USA
dickburk@ix.netcom.com
From: "kabkos" nores1t8j3sp@amverizon.net
Newsgroups: rec.photo.equipment.large-format
Subject: Re: Ground glass..replacements are COARSE!
Date: Fri, 02 May 2003
I have had good luck using an adhesive backed product sold at sign/billboard
shops called "StarDust". I apply it on an appropriately sized piece of
glass and install it with the dull side towards the lens. I have found it
is much brighter than a standard ground glass.
You can also make your own ground glass using the finest silicon grit that
you can find mixed with oil. The grit is available at machine shops in
various grades. Apply the grit and oil to the precut piece of glass and rub
it against another piece of glass. Takes about 20 minutes for a 4x5 ground
glass. This is what I used to do prior to finding the "StarDust" material.
regards,
karl
From: John see@mysite.com
Newsgroups: rec.photo.equipment.large-format
Subject: Re: Ground glass..replacements are COARSE!
Date: Fri, 02 May 2003
"Jim Waggener" jimw@visi.net wrote:
>I thought I may brighten the image with new GG...wrong!
>The old glass on my Kodak Master View is *much* finer than the new. Focusing
>is measurably easier with the old glass. Another waste of money buying a new one.
When the GG in my Zone VI was cracked I replaced it with "non glare"
framing glass. Works fine for me. Had them cut me 4 pieces out of an 11X14
sheet. Total cost was less than $20.
Regards
John - Photographer & Webmaster - http://www.darkroompro.com
Formulas, Facts and Info on the Photographic Process
From: "Richard Knoppow" dickburk@ix.netcom.com
Newsgroups: rec.photo.equipment.large-format
Subject: Re: GG cut corners?
Date: Wed, 30 Apr 2003
"Dean Van Praotl" no.spam@my.email.adr wrote
> "Richard Knoppow" dickburk@ix.netcom.com apparently said:
>
> > You will occasionally see the explanation that the corners
> >are air leaks for the bellows, but the camera back doesn't
> >seal anyway, they are there for the above reason.
>
> Richard, I'm not trying to start a flame war here, but
> that's a little bit like claiming that 35mm cameras
> have mirror lockup to help reduce vibration when
> shooting long lenses or high mag macro.
>
> Adams said the corners of the ground glass were cut off
> "to permit the movement of air when the bellows is
> expanded or collapsed." (The Camera, ch.4)
>
> I'm afraid I have to disagree with you, and side
> with St. Ansel...
You are certainly allowed to disagree with me.:-)
However, look at the construction of most camera backs.
The spring plate, which contains the ground glass and
retains the film holders, does not seal against the camera
back. Most press the holder only at the corners and have an
air passage around the periphery when there is no holder in
the camera. You will find that if you plug the corners with
tape there is little difference in the freedom of movement
of the bellows.
Many cameras do not have cut corners, for instance,
Graphics with Graflok backs and Calumet 4x5 and 8xl0
cameras.
I am afraid Adams was wrong about this one.
---
Richard Knoppow
Los Angeles, CA, USA
dickburk@ix.netcom.com
From: "Richard Knoppow" dickburk@ix.netcom.com
Newsgroups: rec.photo.equipment.large-format
Subject: Re: GG cut corners?
Date: Thu, 1 May 2003
"Jim Waggener" jimw@visi.net wrote
> It appears original to me. The original instruction book for the Calumet
> version shows cut corners in the photographs. {shrug}. I really like this
> camera. The rotating back with the release handle is great.
>
> Jim
Which Kodak Master View? You obviously mean the 4x5 since
the 8x10 does not hav a rotating back.
The 4x5 Masterview, which was later marketed by Calumet as
the CC-400, has cut corners. They are shown clearly in the
Calumet catalogue and in Kodak data books showing the
camera. I have one (a Calumet) but its out in the garage at
the moment and I am _not_ going out there just to look.
I am not sure of the 8x10 version of the Kodak Master View,
which is of a completely different construction. OTOH, the
Calumet C-1 8x10 does NOT have cut corners. My Agfa-Ansco
cameras have cut corners on all backs for sizes 8x10 through
4x5.
Speed Graphics with Graphic backs have cut corners, the
Graflok does not.
Whatever the intended reason for them they are quite
useful for checking the coverage of a lens.
---
Richard Knoppow
Los Angeles, CA, USA
dickburk@ix.netcom.com
From: "Richard Knoppow" dickburk@ix.netcom.com
Newsgroups: rec.photo.equipment.large-format
Subject: Re: GG cut corners?
Date: Sun, 27 Apr 2003
"Jim Waggener" jimw@visi.net wrote
> On a second note, I replaced the GG on my 4x5 with a new one.
> Inspite of cleaning the old one the new GG is measurably brighter.
Snipping.....
The grain of the glass can make a difference. Coarse GG
tends to have an exagerated hot spot in line with the lens
and to look dim overall. A finer grain diffuses the light
more and can look brighter overall although it is actually
dimmer at the center.
Some very old cameras came with rather coarse glass.
Cameras made from perhaps 1940 or a bit earlier are likely
to have fine grain glass, although my Agfa 5x7 view camera
has rather coarse glass in it.
Fine grain round glass is available at reasonable cost
and is not difficult to make. As Jim discovered, it can make
a significant difference.
Ground glass which has become coated with greasy dirt can
look very dim. The cure is washing it in dishwashing
detergent and water.
---
Richard Knoppow
Los Angeles, CA, USA
dickburk@ix.netcom.com
From: "Sherman" sherman_remove_this@dunnam.net
Newsgroups: rec.photo.equipment.medium-format
Subject: Re: Putting a grid on ground glass focusing surface
Date: Mon, 07 Jul 2003
"Rich Shepard" rshepard@salmo.appl-ecosys.com wrote
> I have a couple of backs for my 2-1/4x3-1/4" Galvin view camera: a
> Graflok back and the original Galvin back. I would like to put -- or have
> put -- a grid on the glass so I can more easily align verticals and
> horizontals to correct perspective.
>
> I'm not sure what to use that will produce very thin, black lines and will
> still permit me to clean the focusing glass as needed.
>
> Suggestions welcome.
> Thanks,
> Rich
Rich,
What about printing the grid on overhead transparency sheets and then
cutting the sheet to the size of your gg? Using your computer you can make
the grid any size, make several different ones with different grid sizes and
remove the sheet for cleaning.
Sherman
http://www.dunnamphoto.com
From: "zeitgeist" blkhatwhtdog@yahoo.com
Newsgroups: rec.photo.equipment.medium-format
Subject: Re: Putting a grid on ground glass focusing surface
Date: Mon, 07 Jul 2003
> I have a couple of backs for my 2-1/4x3-1/4" Galvin view camera: a
> Graflok back and the original Galvin back. I would like to put -- or have
> put -- a grid on the glass so I can more easily align verticals and
> horizontals to correct perspective.
>
> I'm not sure what to use that will produce very thin, black lines and will
> still permit me to clean the focusing glass as needed.
art or graphic supply stores just might still carry Pica tape. This is very
thin black (or red) tape that graphic artists used to make lines, borders
etc back in the days when doing page layout and you need to cut and paste
you, well cut, with scissors and pasted with glue or this waxy stuff. So
it came in hairline, and one pica thickness and wider, the one pica should
do you fine.
I did it to my old Nikon F so I would know where an 8x10 crop was.
From camera makers mailing list:
From: "John Cremati" johnjohnc@core.com
To: cameramakers@rosebud.opusis.com
Date: Thu, 18 Dec 2003
Subject: [Cameramakers] Drawing grid on ground glass
You can output a negative with the fine line grid on it and use it to
contact print a photoresist to the glass.. and then acid etch using
Armoral Etching Paste to create a very fine grained ground glass...... You
can then "lightly" sandblast the glass using very low pressure .. This
will give you the best of both worlds where you can pick up detail and have
a more even light coverage over the ground glass... John Cremati
From camera makers mailing list:
From: "graphic99@mindspring.com" graphic99@mindspring.com
To: cameramakers@rosebud.opusis.com
Date: Fri, 19 Dec 2003
Subject: [Cameramakers] DIY groundglass grids
I've had good luck lining off 8x10 cropping marks on 35mm gg screens using
1/64th (?) inch ChartPak brand tape (was available in black plus colors and
I think, transparent red).
Good luck finding this antique graphic arts product.
From: David Nebenzahl nobody@but.us.chickens
Newsgroups: rec.photo.equipment.large-format
Subject: Re: Ground Glass thickness question....
Date: Mon, 15 Sep 2003
dr bob spake thus:
> "Richard Knoppow" dickburk@ix.netcom.com wrote
[snip]
>>
>> The thickness is not critical since the ground side goes
>> against the reference surface. Common ground glass is 1/16th
>> inch thick.
>> I can't make out what you are doing with the loupe. All
>> you need is to focus the image on the ground glass. The
>> distance from the loupe to the ground surface makes no
>> difference at all.
>> You should be able to find GG at around $20 a sheet for
>> 8x10. Its quite practical to make it but a lot of trouble.
>> The finest surface is acid etched. I've not tried this but
>> understand you can get jelled etching solutions at hobby
>> shops. This is an alternative if you can't get a fine enough
>> surface with valve grinding compound (which works) or
>> jewelers rouge.
>> ---
>> Richard Knoppow
>> Los Angeles, CA, USA
>> dickburk@ix.netcom.com
>>
>
> There is an excellent article on making ground glass from scratch (sorry,
> couldn't help it) by Dick Dokas, Photo Techniques, May/June 2003, p. 33.
> While I have never tried this technique for ground glass, I have used a
> similar one for telescope mirrors and it should work, with a little
> patience.
I haven't read the article, but the techinque is so simple it can be given in
a short paragraph:
Simply grind the glass to be ground against another, larger piece of glass,
using any of several types of readily-available abrasives mixed with water. I
found 1200-grit silicon carbide powder to yield excellent results. If nothing
else, use automotive valve-grinding compound, available at auto parts stores
everywhere.
Just make sure the glass (both pieces) are flat. You'll know immediately if
they aren't since there will be low spots that don't get ground.
(Okay, 2 paragraphs.)
from camera makers mailing list:
Date: Thu, 18 Dec 2003
From: "J. Wayde Allen" wallen@village.org
To: cameramakers@rosebud.opusis.com
Subject: Re: [Cameramakers] Drawing grid on ground glass
Duddie wrote:
> I am in process of building 4x5 Field View (own design) and I
> have made my own ground glass and now I got the problem of
> drawing grid on it.
> I have two questions about grid.
> 1. What kind of paint, tools, methods would you suggest for
> such job?
Your computer printer and a piece of acetate film would work pretty well.
Just print the grid and place it over the back of the ground glass plate.
- Wayde
(wallen@village.org)
From: Brian Walton [info@dotco.co.nz]
Sent: Sun 9/28/2003
To: panorama-l@sci.monash.edu.au
Subject: Re: Custom Ground Glass
Try http://mejac.palo-alto.ca.us/leica-users/v01/msg01959.html
Brian
From: George S. Pearl [alps007@mindspring.com]
Sent: Mon 9/29/2003
To: panorama-l@sci.monash.edu.au
Subject: Making Ground Glass...easy!
Hi Ya'll,
You know, I made some ground glass once upon a time by just getting some clear 1/8 inch or 1/16th inch clear glass
and then applying some frosted sticky overlay film to the glass. Sounds like it could not possibly work, but the
results were terrific. There was no difference that I could tell between the real ground glass and my invented stuff.
The film is applied using some soapy water sprayed onto the glass and then pull the release paper off of the
overlay film and stick it on. Just set the sticky side of the film onto the glass and then squeegee out all of
the water and bubbles. Let the glass and film dry overnight before you trim around the glass any film hanging
over. Just cut / trim it off with an exacto blade. There you have it! Pearl's secret recipe for making your own
ground glass!
The name of the overlay film to put on the glass is called:
3M Scotchcal Electro Cut Marking Film made by the 3M company. Just find a 3M dealer in your area and
order a roll or two. If you have a little extra, send me a couple of feet :-)
My best,
George S. Pearl, QPP
Atlanta Panorama / ALPS Labs
----- Original Message -----
From: steven blumenthal
To: Panorama-l@sci.monash.edu.au
Sent: Monday, September 29, 2003
Subject: Custom Ground Glass
Does anone know a source where you can get ground glass for focusing cut to a custom size (6 X 24 cm)?
Thanks - Steve
ssblum@comcast.net
From: "Richard Knoppow" dickburk@ix.netcom.com
Newsgroups: rec.photo.equipment.large-format
Subject: Re: help with Kodak 2D 8x10 groundglass
Date: Sun, 11 Apr 2004
"Chase Martin" cmartin@cox.net wrote...
> I recently bough a fixer-upper Kodak 2D 8x10 wood camera and have
> repaired the bellows and refinished the wood. My problemnow is that
> it didn't have a ground glass with it. I have a local glass company
> who said they could make a frosted/ground glass to replace it if I
> could find the glass dimensions. So, can anyone help me with the
> dimensions of the ground glass (length, width, thickness?) Also, are
> the corners "clipped" like some groundglasses I've seen? Is it
> "ground" on just one side? If just one side, which side goes OUT
> towards your eye?
> I know there are aftermarket groundglasses that can be purchased (at
> high cost, though) - my local glass company says it will cost me under
> $10 if I provide them the dimesions. Since this is a fixer-upper
> project, I'd like to do it as inexpensively as possible - if you know
> of another inexpensive source (for 2D 8x10 glass) please let me know.
> Thank you for your time!
> ~Chase~
I used to get ground glass from Edmunds before they sold
off the company. I checked the Edmund Optics Co. They still
have ground glass but the price of an 8x10 sheet is up to
nearly $30 US. If this is the same stuff they used to sell
its quite fine grain, similar to the ground glass originally
supplied by Graflex and Kodak. Their glass is the right
thickness and should be drop-in for the 2-D other than
trimming the corners. There are several sources of ground
glass on the web but I have no idea of their relative
quality. My guess is that the glass shop doesn't know what
sort of glass this is.
---
Richard Knoppow
Los Angeles, CA, USA
dickburk@ix.netcom.com
From: "Richard Knoppow" dickburk@ix.netcom.com
Newsgroups: rec.photo.equipment.large-format
Subject: Re: help with Kodak 2D 8x10 groundglass
Date: Sun, 11 Apr 2004
...
The dimentions for most 8x10 view cameras are, guess what,
8x10. You can measure the exactl dimentions by measuring the
internal rebate that holds the glass.
2-D glass has the corners cut out. Glass cutting is
easiest done with a carbide scribe. You can get one at most
hardware stores for will under ten dollars. Don't try it
with the usual wheel window glass cutter. Standard camera
ground glass is 1/16th inch thick but a few cameras, the
Calumet C-1, for instance, take 1/8th thick glass.
Commercial fine grain GG should cost about $20 for an 8x10
sheet. Smaller sheets are not proportionally cheaper because
they must be cut down from an 8x10 sheet.
From: "Richard Knoppow" dickburk@ix.netcom.com
Newsgroups: rec.photo.equipment.large-format
Subject: Re: Drawing Grd Lines on Ground Glass
Date: Sun, 11 Apr 2004
"Jack" TeeMax@film.net wrote
> Can someone suggest a way of drawing grid lines on plain 8x10 ground glass?
> I'd like something that would be reasonably stable (i.e. wouldn't just rub
> off in use) but that also could be removed if a mistake was made. I guess I
> could always use a Sharpie pen and a ruler but I'm not sure how stable
> and/or removable a Sharpie would be, nor am I confident that I could get the
> lines perfectly parallel that way. Seems to me I've seen suggestions to use
> Photoshop to make the lines on a piece of clear film and then somehow attach
> the film to the ground glass but I'm unclear on the details.
A Sharpie will work fine if the lines are fine enough for
you. The ink comes off with Isopropyl (rubbing) alcohol. I
just tried this on the ground side of a scap of GG to make
sure.
---
Richard Knoppow
Los Angeles, CA, USA
dickburk@ix.netcom.com
From: "Nicholas O. Lindan" nolindan@ix.netcom.com
Newsgroups: rec.photo.equipment.large-format
Subject: Re: Drawing Grd Lines on Ground Glass
Date: Sun, 11 Apr 2004
"Jack" TeeMax@film.net wrote:
> Can someone suggest a way of drawing grid lines on plain 8x10 ground glass?
A pencil is the norm. Use a .3mm lead, holding the pencil vertically.
The pencil is applied to the ground side and so is protected from smudging.
If you are confident of your skill then a Rapidograph and India ink is
a better choice.
To keep lines parallel use a T-square, carpenters' square, drafting
triangle, drafting machine ...
The grid lines I know of are either silk screened to the back,
smooth surface, of the glass or are made as 'unetched' clear
grid lines on the ground side.
Another alternative is to apply thin black tape to either side. Art
supply stores should stock some.
If you want to use an overlay then I would suggest the line draw feature
in a word processing, spread sheet or CAD program. Photoshop lines are
neither precise nor accurate. Attach the overlay to the smooth side
of the glass, printed side towards the glass.
Precision optical overlays that I am familiar with were made from
lithographic negatives. Draw the artwork on a sheet of paper and
use the camera to photograph it's own grid overlay - you will have
to contact 'print' a positive film. Alternately, if you have a
friend who does printed circuit layout, he can have an
ultra-precise lithographic overlay made for you.
Heavy clear silicon grease works well for laminating plastic to glass.
You have to be very careful not to get air bubbles, though most can be
removed with a print/inking roller.
--
Nicholas O. Lindan
From: "AArDvarK" noway@yourprob.com
Newsgroups: rec.photo.equipment.large-format
Subject: Re: Drawing Grd Lines on Ground Glass
Date: Sun, 11 Apr 2004
Not a sharpie, permanent ink in the rough?
Not me...
A mechanical pencil with softer lead (single
thinness size and darker) for the markings,
a small architect's T-square (cheap plastic)
for guiding the pencil and maybe metal ruler
for measuring.
I do suggest the T-square have an edge that
is flush with the surface rather than "stepped
up", because the "up" kind can allow [one] to
"slur" the line somewhat underneath it or
outward, which is no bueno.
You can also buy clear templates from:
http://stores.ebay.com/Aletta-Photographic
... cheaply, you add it to [in] your glass
clips on the camera, outside the glass.
... hope this helped,
Alex
From: "Richard Knoppow" dickburk@ix.netcom.com
Newsgroups: rec.photo.equipment.large-format
Subject: Re: Satin snow ground glass
Date: Sat, 17 Jul 2004
"Argon3" argon3@aol.com wrote ...
> Howdy...
>
> I was going to order some groundglass from Satin Snow....the original glass on
> my camera seems a lot dimmer than I think it should be and I hear that a finer
> groundglass can give a brighter image.
> Has anyone used a Satin Snow glass and found it to be an improvement? I've
> seen links to Photo.net wherein there's a thread about making one's own
> groundglass and using finer abrasives than are usually used and this seems to
> be what the Satin people are doing. Any experiences in this regard?
>
> thanks
>
> argon
Finer grain GG will make the illumination more uniform
and is easier to focus on but won't make the image much
brighter. Before investing in the glass try washing the
glass you have. If the ground side gets a bit greasey it
will become a bit more transparent causing it to have a hot
spot and look grainy. Dishwashing detergent in warm water
will work fine.
I am not familiar with Satin Snow. There are three ways
of making ground glass. One is to sand blast the surface,
this yields the coarsest surface, the next finest is
grinding it with rouge, the third method is acid etching.
The last gives the finest surface. That may be what this
outfit is doing.
I used to get very satisfactory GG from Edmund Scientific
but it was no longer in the catalogue after the company
split into two. I think Edmund Optical may still have it.
A tip, ground glass is best cut using a carbide scribe.
The familiar wheel type window glass cutters will cut it but
not very accurately. You can get a scribe from a hardware
store for less than $10 US.
---
Richard Knoppow
Los Angeles, CA, USA
dickburk@ix.netcom.com
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