this post does not supply iodide, a necessary nutrient!Theodore Gray:
Interesting fact about iodine vapor: You can't photograph it against a black background. Absolutely cannot be done, period.
Colored gases are extremely uncommon. In everyday life, any time you see air that does not appear perfectly clear, it's because there is a particulate smoke of some sort in it. (Fog, for example, is a smoke of water droplets.) You virtually never see colored vapor that isn't smoke, so even though I should theoretically have know it was impossible, I spent about half an hour trying to pour more and more light into the side of my iodine vapor to make it show up against a pitch black background. Only after I had several thousand watt-seconds of studio flash light concentrated on it did I suddenly realize the complete futility of the exercise.
So now you know why iodine is one of very few samples in my poster that are not photographed against a black background.
if only he'd asked himself if iodine vapor fluoresced
(it does)
