Success. I have created a ground glass focusing screen for the 8×10 camera body. Perfect? No. Functional? Yes. I’m getting more used to that. I used the same process as before – clip the corners, lap the corners and then grind the glass on a larger piece of glass using the fine grit valve grinding compound. Only this time I diluted the grinding compound with a couple of teaspoons of sewing machine oil. I used very little grinding compound.

I still ended up with some small “bare spots”.  Since it was getting harder to move the full piece of glass around, I decided to use a broken piece of glass from the earlier failed attempt to “spot polish” the bare areas. This worked, but turned out to be an error because the spot polished areas are no longer uniform with the remainder of the ground areas. The difference doesn’t really impair the function of the glass but it is noticeable. The other thing that didn’t turn out quite right is that the new piece of glass had some imperfections I didn’t notice when I bought it. There was a scratch on one side, and a few minute surface chips along one edge. I put these on the ground side and they didn’t completely grind away. Again they are noticeable but not really critical.

Here is a photo of the finished product. Note special adhesive material used to replace missing spring clamp. :)

I am growing in respect for the first daguerreotypists who worked from only the sketchiest of instructions and without benefit of the web. They built cameras from scratch and made (in many cases) beautiful and compelling images.

2 Responses to “Glasswork”

1. Jon says:

   June 8, 2008 at 12:23 pm

   That’s awesome you made your own ground glass. It’s something I’ve often wanted to try. When I made a camera with a photocopier lens I used wax paper as the ‘ground glass’ but I had problems getting it at the same focal plane as the film.

   The first daguerreotypists had to be incredibly skilled at all sorts of crafts and had to have a good idea of how the camera and process worked. I’m sure there was plenty of trial and error, mostly error. Though safety wasn’t necessarily something they were really restricted by as contemporary daguerreotypists are.
2. andy says:

   June 8, 2008 at 4:40 pm

   Thanks Jon, I think I can recommend it as a fairly “beginners” project. If I did it again I would inspect the glass prior to purchase, and I would use a much finer water based grit. One source recommended 600 grit aluminum oxide.

   I have added a photo link to the post.

   I have been thinking a lot about the issue of getting the ground glass and the film/plate in the same focal plane, because I need to tackle film holders next. It looks to be a challenge, especially since I don’t know what the tolerances are.