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Old 11-03-2007, 11:16 PM   #34
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Join Date: Feb 2007
Location: Grand Rapids, MI
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Originally Posted by JRMDC
Jim, it's cumulative exposure to light that matters. Dark sky can't mask because dark sky does not increase the exposure. If you tried a double exposure and the second image were blue sky instead of night and a moon, you would end up with overexposed blue sky in the final image and a loss of everything in the first exposure.

Put another way, a dark exposure does not paint the negative black! It's the absence of light, not the presence of a black shade of light.
Ok, that makes perfect sense. I guess I'd never even contemplated the concept of double exposures with film...although in my youth, it happened a few times with crappy cameras...and the results were bizarre, yet amazing to a youngster who didn't know better.

Alright, and since the moon is MUCH brighter than stars, the time it takes for a perfect exposure of the moon would not be enough time to allow stars to saturate the previous photo.

Everything makes sense now. Thanks, guys.

Now...I suppose it's safe to say that the original picture in question is a double exposure. So presenting a "fake" scene with a double exposure is acceptable on RP, eh?
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