Pinhole Photography

I was invited to organize and hold a workshop on Pinhole Photography and I have been preparing myself on this. I first transformed a tin box with about 10 cm diameter in a pinhole camera. That was very easy, the only difficulty is to make the appropriate hole that is said to be optimized for 0,446 mm. I searched in my needle box for a needle or pin with a convenient diameter and found 0,5 mm.
But the metal of the round tin box is thick what will restrict very much the image circle. So I made a larger hole, 4mm diameter, and glued over this hole and inside the box a thin film of acetate with aluminium tape and then perforated this film and aluminium adhesive together with the 0,5 mm pin at the middle of the 4 mm hole.

First version of my pinhole camera

After this was done, I tested the camera with VC Ilford Paper MG IV developed in a home brewed Parodinal developer in dilution 1:5. Not bad...

Pinhole photo inverted with Photoscape

After this succeeded test of the RTB (Round Tin Box) I decided to upgrade the camera with the possibility of using 52 mm filters in order to control better the contrast. I prepared a ring of a PVC tube with 50 mm diameter in order to fit the cylindrical surface of the box and glued it with epoxy around the larger hole. Finally, again with epoxy, I glued a 43-52 step-up adapter to the PVC. And this was the result. An additional vantage is to use a 52 mm cap as shutter.

Upgrading my pinhole camera

New test with low contrast, green filter:

To be continued...