Brighter Ground Glass

[Jim Reed]

The most amazing thing! I just gained about two stops of brighter image on my old ground glass BY ACCIDENT. I still don't believe it but here's what happened: I'm finishing up my home made 5"x12" panorama ULF and I'm restaining the body and the new add-on parts. I'm using regular ole Minwax Natural Wood Finish and accidently brushed a little on the ground glass. A spot about the size of a quarter. Just enough to be very annoying and pretty much in the central part of the glass. Well the stain acted just like water and made a clear glass spot, expept it dried almost instantly and wouldn't wipe off. Damn to hell! I'm going to have to grind out that spot for sure if some thinner of some type doesn't remove it.

So the camera gets done, I hang a little G-Claron 355 on the front, insert the ground glass carrier, and focus in for the first time using my newly installed bellows attachment. Wow. Experiance the THRILL. Dissect the TACTICS. Whoops. Sorry, thats Dog Fighters on TV. I just experianced the thrill.

But then I looked at the big bright "stained" spot. IT SHOWED THE SAME FINE DETAIL IMAGE as the rest of the ground glass, but at least TWO stops brighter.

If you don't believe it, try it. Has anyone else discovered this, or does everyone already know about it and it's just one of those things I've managed to miss for all these years?

[Dave Parker]

Jim,

I discovered this several years ago, two caveats you want to be aware of, with the thin layer of wax, in hot weather, it will melt and run, and become uneven, and in cold weather it will become very brittle and partially chip off with the flex of the camera..

As far as 2 stops brighter, I would be suspect on how you measured this to derive 2 stops.

Now of course, Wax has been a base part of some of the enhanced screens for years..

Dave Parker
Satin Snow Ground Glass

[Jim Reed]

Dave

[Maris Rusis]

This is an old trick but a good one. A tiny drop of oil in the centre of a ground glass will spread to form a spot with a much brighter image and this is darn useful when viewing through dim lenses but there are trade-offs.

The oil spot offers less focussing certainty than dry ground glass but the increase in brightness may make up for this.
A lens with a big exit pupil gives better results than, say, a 90mmf8 with a small pupil.
Oil spots don't work very well away from the centre of the ground glass and are effectively useless in the corners.

[Dave Parker]

Dave

Jim?

[EuGene Smith]

Dave. Jim. Father and child reunion?

[Pete Watkins]

So, Dave, are you grinding glass for us again? I'll contact you if you are!
Best wishes,
Pete.

[Dave Parker]

So, Dave, are you grinding glass for us again? I'll contact you if you are!
Best wishes,
Pete.

Pete,

I have not stopped grinding glass, I am still filling the orders I have on file, unfortunately with my back, I am being slower than I anticipated, (Word to the wise, Never break your back!!) we are continuing to fill orders as fast as possible, I have virtually stopped taking orders for now, I have not decided what I will do, when I get the approximately 300 orders I have on file filled, I am thinking about selling the business, but that is only one option. I made a large mistake, and that was not only taking orders from retail customers, but I accepted orders from manufactures, so that really got me in trouble, it takes a good month to fill one manufactures order, which is normally in the hundreds, which does not allow me to fill retail orders...


So at this time, I am currently trying to fill everything I have...

If I decide to start taking orders again(retail) I will be sure and post a note to let everybody know.

Thanks.

Dave

[Pete Watkins]

Thanks Dave. Good luck and keep healthy.
Pete.