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Light from Behind — can’t get look right
I’m trying to get the look of a light passing behind a transparent image.
Imagine what it would be like if you laid a slide (35mm transparent photo) on the bed of a scanner or a photocopier, and then watched the scanning light pass behind it: the light as it passed behind, would blow out part of the image, but part of it would also look sort of right, and then the image would sort of ‘drop off’.
My problem is getting both this partial blow-out effect and the drop-off effect looking correct as I animate light behind the image (so far, I’m just using white solids or white objects of various kinds/shapes/gradients etc. behind the image — this approach might be wrong? Maybe they have to be in front of the image, I dunno
— or, maybe it’s a gamma curve issue somehow: in that the ‘drop-off’ in the natural conditions I’ve described above needs to look different from what you’d get if you just ramped the gamma for instance, or ramped down the brightness or contrast of the image there, or multiplied the image against the ‘light source’ behind. I’ve tried other composite modes as well, but none of them seem to get it quite right. I wonder if someone else has done this before and there’s an example I can follow?
Might have to comp multiple versions of the same image over the ‘light source’ layer I’m thinking…any help appreciated.
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4 Replies
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A-ha — OK, that sounds right. Is there a way to use an animated file — let’s say a grayscale animation which represents the movement of my lights — as an adjustment layer itself?
Or do I have to represent those ‘lights’ only by masking and feathering the adjustment layer(s) which are otherwise simple solids?thx
LMN
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— oops, scratch that. It’s pretty obvious that any layer can be an adjustment layer, it’s based on Alpha I guess. Or I can track matte an Adj Layer to the file, no problem.
Interesting interplay when using AE 7’s exposure effect, including its gamma controls — turning the exposure down and the gamma UP on the picture layer, then applying exposure in the adjustment layer to bring gamma back down and exposure back up according to the ‘lights’… much closer
thx
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You might try having two versions of the image, one that is the image without the light behind it, probably a little muddy looking and the other would be the image that is blown out and bright. you could then use an animated mask to “scan” across the blown image.
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