Inspired by some amazing photos of the sun’s path, I decided to put together a pinhole camera. Fortunately (or possibly unfortunately when I see the results after a few months), I didn’t have any photo paper and had to improvise. I’ve been making PCBs using a photo-sensitive thin-film mask over the copper.  I’ve also been experimenting with glass etching using HF acid.

The process I’m going to follow will be to expose the sensitized glass, develop it in a basic developer, and then etch in HF acid. The areas of the light sensitive film receiving light should become “hardened” so they adhere to the glass after the development process and during the etching process. The end result should be that dark areas of the exposure are frosted (opaque) and the light areas of the exposure are see-through. I also hope to complete the process on a piece of copper board leaving copper in the light areas and nothing in the dark areas.

Pictures are of the (hopeful) view, and the camera itself, lashed to a railing.

I’m not quite sure how long to let it go. Normally, the film takes 15 minutes to develop under a 100W full-spectrum lamp at 10 inches. I’m guessing with a 1/16″ diameter hole, it could take months.  Fingers crossed, I don’t want to have to repeat this…

Update

I was impatient and peeked at the film as it was progressing. The blue color indicates it has been exposed while the greenish color indicates non-exposure. As you can see, the skyline was recorded–the bright sky causing the blue exposure and the buildings due to their non-reflectivity, left parts unexposed. Unfortunately, there must not have been enough light because developing the film ate away the exposed areas as well. Back to the drawing board.