Why do things look darker when they're wet?
I've got an idea to fix the crappy automatic brightness sensor on my Android phone. Will it work / screw anything up? [more inside]
What causes laser source speckle patterns, and why do they remain constant even if the observer moves?
Why doesn't the speckle pattern that you see around the source of a laser change when you move your head, and what causes the pattern? [more inside]
Help me solve an optical puzzle. How might I make this fictional camera obscura work, given the parameters of my fictional location? [more inside]
Let's say I'm toying with the idea of making my own scanner for negative film. I've found a suitable sensor, and the rest of the mechanism looks manageable. Can I get a suitable light source that will compensate for the orange mask, at a reasonable price? [more inside]