[LargeFormat] Ground glass or etched

[Brock Nanson]

One thing I would add to this (although I have not made my own glass) is 
to be sure the glass is dry before evaluating just how 'ground' it is!  
When wet, the water fills the tiny scratches and makes the glass appear 
un-etched.  Or so I found when I washed 40 years of grime off of mine!

Philip's process sounds like one to try IMHO.  Assuming you have a fresnel 
lens in place also, it shouldn't take much to catch the image.

Brock

On Tue, 24 Dec 2002, Philip J. McCourt wrote:

> Philip,
> Why not just make your own? I have made a few of them now and they have 
> turned out very nice. The powder that I use is simply 600 grit.  Making 
> a ground glass should take about 20 minutes of your time. I simply buy a 
> cheap picture frame for  the glass.  The quality of the finished product 
> will amaze you, the image is bright enough to see in daylight without a 
> dark cloth.
> 
> The powder can be found at lapidary supply stores. (rock polishing 
> compound)  I have talked to people that have used fine rubbing compound 
> used for rubbing out auto finishes.  The stuff I use is a 600 grit 
> aluminum oxide. Just put a little bit of powder and a tiny bit of water 
> between 2 pieces of glass and start moving the glass in a circular 
> motion for about ten minutes. Wash it off and then check to see if the 
> glass is done yet. This method will give a very fine surface for the 
> image and is a joy to use and focus the camera. Also it is cheap enough 
> to carry a spare with you in your kit.
> 
> I have used acid etched glass and sandblasted glass and this homemade 
> glass is by far the best yet.
> 
> If there is enough interest I will put together a "how to" page on my 
> web site for making ground glass.
> http://www.philsan.com
> 
> Philip McCourt
> 
> philip.lambert wrote:
> 
> >I am having difficulty getting a replacement focussing screen in the UK for
> >a Speed Graphic and a Century Graphic. Mr Cad has kindly offered to sell me
> >an old screen to cut down but old glass is brittle and tricky to cut, even
> >though it involves only straight line cuts here.  The alternative is to
> >import a Boss screen which would work nicely when eventually received but
> >glass is cheaper, when you can get it. The only possibility I have heard of
> >is 2mm sandblasted, an example of which looked very white and I can imagine
> >how dim an image would result.
> > Does anybody know a source of new glass in the UK?   Thanks a lot.  Philip
> >
> >
> >
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-- 
Brock Nanson
Kamloops BC Canada