Someone at rangefinder.com did a comparison between different screens for the Rolleiflex. It appears that the brighter screens (some with fresnel) are very nice but not so good for focusing - the original darker screens (without fresnel) are best for focusing. With respect to Rolleiflex, my experience is that the original Rollei screens have the best of both worlds: quite bright (not the brightest) and easy for focusing. Guess it is the same with GG's for LF.
It's an inherent trade-off between brightness and evenness. A more granular screen, one make with coarser grit, will show a brighter center but darker corners, a least when viewed from the center of the screen, than one made with finer grit.
For 8x10 studio work, I keep a whole page magnifier, i.e. a Fresnel lens, handy for composing. I simply hold it up again the ground glass. By moving the Fresnel around a bit, I can lighten up the edges of the image varying degrees. Once I have rough focus and composition, then I set the Fresnel aside and do fine-focusing with a loupe on the ground glass.
For soft focus lenses, on the other hand, I don't use a loupe. I focus by eye, watching how various parts of the image come into and out of focus.
“You often feel tired, not because you've done too much, but because you've done too little of what sparks a light in you.”
― Alexander Den Heijer, Nothing You Don't Already Know
I haven't read everything here, but I am impressed by an early post on the delicate and meticulous cleaning of the GG after all the grinding. My question is: After an initial rinse , can the sheet of glass be placed in a regular dishwasher and run? We have washed some fine glass household items without damage and the cleaning products leave them clear and streak-free.
This may be a very bad idea for a freshly ground GG . . .I just don't know.
Drew Bedo
www.quietlightphoto.com
http://www.artsyhome.com/author/drew-bedo
There are only three types of mounting flanges; too big, too small and wrong thread!
I just wash by hand in sink with dish soap and hot water. Clean as can be.
Tin Can
In another life I ran a C02 Laser engraver, mainly for engraving rubber stamps, but I did have a rotary attachment for glass engraving. We did do some fiddling with rotary engraving on bottles, and drinking glasses/tumblers and this was a mildly acceptable result.
Once the Laser engraver had engraved, (actually it heated up and melted the smooth surface of the glass) to what sort of represented a ground glass screen, it was a bit rough to touch what with tiny particles of glass here and there. As we at this stage were still fiddling and learning, we wondered about throwing one through a dishwasher cycle, we did.
The result was pretty good, so good in fact that we from then on put everything glass we lasered through the dishwasher, except for new full bottles of wine with their shiny labels on.
One thing we did find, the eco setting with the wash cycle running around 50ºC wasn't that great, the best was the hottest cycle running around 65ºC with a total washing time of around 73 minutes, including the drying cycle.
Glass came out bright and shiny. I have just had a look at two of those glasses, which were lasered around 16 years ago, they still look good and have been through numerous normal wash cycles at 55ºC. Those glasses soon lost their real shiny look, but essentially, running them through a dishwasher cycle hasn't harmed them.
I myself having just purchased some 6mm glass to grind my own ground glass, I will be running at least one ground glass through a dishwasher cycle.
Mick.
I've read nothing in this thread about deburring the glass, if you cut the glass yourself or get one with sharp edges it's good to deburr it with a grinding stone or middle fine good quality grinding paper.
I made some ground glasses and I must say for whole plate and 8x10, I find it quite a lengthy process, I wash and change the carborundum many times, maybe 10 times, before I'm satisfied.
I have used carborundum 400 and 600, (silicon carbide in europe) and prefer the 600, but would have to do more comparisons really.
What I noticed when I had to make a ground glass for my Gandolfi is that the original ground glass had darker look to it but lighted up better in use.
My understanding so far is finer is better for focussing, coarser is more bright, also to the corners.
Different grits can be used on different parts of the ground glass.
I also heard that the old guys applied wax to their ground glass (or parts of it of course) for focussing.
Seems logical, you fill up the holes and the grind gets finer.
All said and done, I would like to have an 8x10 acute matte D viewing screen, but if they exist would probably cost more than a few view cameras :-)
For cleaning the frosted site of the screen, see here:
http://www.largeformatphotography.in...f-ground-glass
Here's a video I made that shows you how to make a ground glass. https://www.youtube.com/watch?v=hxC48_sd6BM
Thanks for watching,
Tony
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