What did Hopf and Satin Snow do differently during ground glass production?

[williaty]

As part of getting my new Eastman 2D back into fighting trim, I had to come up with a ground glass. Initially, I followed some online directions that suggested using 5um white aluminum oxide followed by 3um white aluminum oxide and the results were HORRIBLE (absurd hot spot, hard to know exactly when it was in focus, could see the lens aperture through the GG). I then found some 600 grit silicon carbide at a local rock shop and that produced a much better screen. This got me to thinking, is a 600 grit silicon carbide screen as good as it gets (for me)? That led me to wondering about what the manufacturers who produced straight ground glass (no fresnel or other add-ons) who are so loved by the community actually did to produce the results so many people love.

Does anyone know what the production process for the old Satin Snow ground glass or the more recent Steve Hopf ground glass was? From reading old threads on here, I know Hopf's old website had a DIY page but it's long gone. I'd be interested in making a few in either of their methods to compare to the other two I've made and see what I prefer.

[Tin Can]

There are more ways to make a GG than grinding. Etching by media or chemistry. Coatings like a KMV. Tape which falls into film layers. Heck dirt and glue might work.

There are also many differences in ground glass over history. I have a very course ground Linhof OE 4x5. Different.

Also Aerial Focusing. Read this thread. Lots of good info. http://www.largeformatphotography.in...l=1#post433645

[goamules]

I've used 5 micron Alum Oxide to great success. It may be your technique was wrong.

[Ron Stowell]

I've used 5 micron Alum Oxide to great success. It may be your technique was wrong.

Holgamods listed on E-Bay can produce custom size ground glass, reasonable priced and good quality.

[Alan9940]

Wasn't there someone on these boards that recently posted a thread about him making gg? And, at reasonable prices, too, IIRC. I'd suggest doing a search here, if you're not going to make it yourself.

[Willie]

My Uncle has made a number of them in various sizes up to 12x20. Sand blasting was the method used. Sand from a commercial glass blaster that was being dumped as it was at the end of the cycle and worn down into smaller grains. made nice ground glass for a number of cameras.

[DrTang]

I've used wax paper

[BradS]

I was under the impression that Steve Hopf was still making focusing screens.

Dave Parker (satin snow) was a member here. He was a craftsman who took great pride in his product. He made excellent ground glass focusing screens and although he occasionally hinted at his methods and tools, he was fairly quiet about the details. It was my impression that Dave had developed a machine to facilitate production.

[John Layton]

Super cheep: stretch magic tape across film plane of gg frame. Works (until it doesn't)

Cheap: oversized plate glass, 500 grit carborundum, picture glass (sized to gg dimensions), a teaspoon of grit on the plate glass, a few drops of water, picture glass placed on the grit/water slurry, move picture glass in a circular motion (wear rubber gloves for friction) until grit gets distributed into a thin layer under the entirety of the picture glass. Do this for a couple of minutes. Rinse and repeat two or three times, rinse and look for any unevenness - repeat grinding if necessary. Use this glass by itself...or slap a page magnifier over it to increase evenness of image and increased brightness. Works.

OH...and don't clean off the plate glass - but instead let it dry in a vertical orientation...the resulting dendritic patterns will blow your mind! (you may want to make a photo of this!)

Lots of other commercially available options. (I prefer Maxwell by a long shot - worth the cost of a lens...and why shouldn't it be?)

As for "out of the box" DIY-ing...I've heard of a technique - applying something like thinned out polyurethane to the ground surface of a diy glass to make it brighter, but I'd imagine it would need to float low enough to allow some texture to rise above the dried poly...otherwise the glass would pretty much go back to useless (be really bright though!).

Gotta get back to shoveling snow (sigh).

[Ray Van Nes]

I posted several ground glasses on the Classified which I cannot find myself but in there I have an 8 x 10 ground glass which is exactly 8 x10 in. May save you a lot of grief.
Cheers
Ray