Your 40-watt bulb has to be fairly close in proximity in order for the light to make things more visible. And since movie screens are so big, you have to be fairly far away in order to see the whole picture.
The energy output from light follows the inverse-square law, so double the distance is 4 times less bright, and quadruple the distance is 16 times less bright.
So although the energy output is higher, it's probably not as bad as you think it is.
I never meant to imply it was bad. Looking directly at a flash bulb like that from typical movie-viewing distance is perfectly harmless. I would not want to look at one up close, however.
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Your 40-watt bulb has to be fairly close in proximity in order for the light to make things more visible. And since movie screens are so big, you have to be fairly far away in order to see the whole picture.
The energy output from light follows the inverse-square law, so double the distance is 4 times less bright, and quadruple the distance is 16 times less bright.
So although the energy output is higher, it's probably not as bad as you think it is.
I never meant to imply it was bad. Looking directly at a flash bulb like that from typical movie-viewing distance is perfectly harmless. I would not want to look at one up close, however.