Adobe After Effects Forum
Sample Scene Lighting
Sample Scene Lighting
by Samuel Hall on Oct 23, 2012 at 5:53:10 pm

Is there any easy way to automatically sample changes in lighting in a file and apply those changes to a color solid?

What I'm doing is tracking (using Mocha) a solid surface and replacing the content within it. The lighting is changing dramatically though.

So far I've just tried applying a "Fill" effect to the layer and using the eyedropper to sample the relevant color changes manually, using keyframes. There must be a better way.


Samuel Hall

Re: Sample Scene Lighting
by Vishesh Arora on Oct 23, 2012 at 7:00:26 pm


It will be better if you could upload the Before and After JPEGs.

Vishesh Arora
3D and Motion Graphics Artist
Films Rajendra


Demo Reel(3D):

Re: Sample Scene Lighting
by Walter Soyka on Oct 23, 2012 at 9:10:22 pm

[Samuel Hall] "Is there any easy way to automatically sample changes in lighting in a file and apply those changes to a color solid?"

GenArts Sapphire has S_FlickerMatch, which can do a pretty nice job.

Alternately, you could write an expression using sampleImage() to link a parameter to a visual. See Dan Ebberts's obscuration example [link] for inspiration.

Walter Soyka
Principal & Designer at Keen Live
Motion Graphics, Widescreen Events, Presentation Design, and Consulting
RenderBreak Blog - What I'm thinking when my workstation's thinking
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Re: Sample Scene Lighting
by Conrad Olson on Oct 24, 2012 at 1:22:42 am

If the camera doesn't move too much try this:

Duplicate your footage and freeze frame one copy.

Blur both layers a lot and the same amount.

Switch the blending mode to subtract. You now have the difference between the frame you froze on and the current frame. You might need to put your project into 32 bit to allow negative vlaues.

Precomp these two layers and place the precomp above the solid. Set it to add.

You can adjust the blur amount. Smaller blur will give you more localised differences but will fail if the movement between the two frames is too much. Bigger blur will just give you a more general difference in lighting.

If you do the same thing but set the first blend mode to divide rather than subtract and the second to multiply instead of add you can match colour rather than brightness.


Re: Sample Scene Lighting
by Ross Shain on Oct 29, 2012 at 4:52:43 pm

mocha Pro has the ability to do auto luminance matching. While this is capability is found in the Remove Module, you could potentially use it for image insertions as well.


Ross Shain
Imagineer Systems