Old Timey Camera

[generalmeow]

Any limitations as to the size of box you build for the print? With pin hole cameras the size limitation is only with whatever materials you can scrounge to build your camera and the size of photo paper you can find. How is focusing accomplished do you need to expose and develop a throw away print before your final exposure?

There is no limitation to the size. Theoretically you could build a gigantic camera and take poster sized pictures (and some people do). The downside would be the cost of the chemicals. You have to coat these with a silver nitrate solution, and it's not cheap. And would be really expensive to have enough of it to make a bath to coat a huge plate (thousands of dollars probably). You would get hundreds or thousands of pictures out of it, but just the money up front you would have to spend is prohibitive.

It's kind of difficult to explain the focusing, but you'd understand it immediately if you saw it. I have two little boxes that I put in the back of the camera. The first doesn't have a back and contains a piece of glass sprayed with a frosty spray paint from a craft store. When you have that in the camera, and you have the lens cap off, the light shines back through the camera and onto that piece of glass. And the frosty coating captures the light, allowing you to see the image coming through the lens. The back of the camera moves in and out which allows you to focus.

Once you have focused on that piece of glass (technically called the ground glass), I tell the subject to not move a muscle, remove that box completely and insert the second, light-proof box, which contains the piece of glass coated by the chemicals. I coated the glass back in a dark room and closed the box to keep it light proof, so I can't actually see glass. But both boxes are constructed so that the pieces of glass are in the exact same position and plane. So once the camera is focused on the ground glass in the first box, I know it will be focused on the coated piece of glass that I can't see.