You can also create amazing Solargrafias with pinhole cameras made this way. I have made some out of Red Bull cans and even film canisters. I was introduced to them by Diego Lopez Calvin. Here is his site:

Introduccion Solarigrafía

I used black and white photo paper and let them expose for 6 months. I then took the paper and scanned it and inverted in Photoshop. No other steps required. Just patience. Below is one of my images. I quickly realized I didn't have the patience for this kind of work so I moved on.

Solargraph Camera #3 - color corrected