Expression:color -> transform

[Anonymous]

Hi,
i’m playing a bit with expressions in Nuke. What i’d like to know is if it is possible to link a color value with a transformation value. I’d like to make scale parameter of the Transform node to reflect the value of the red color channel of the input image eg. something like Transform1.scale = ????.red. Is this possible? How?

Petr

[Anonymous]

This may be a method:

Attach, for example, a Color Correct node after your input(read) node.
Uncheck the “green” and “blue” checkboxes in the “Layer” section. Anything you correct, say, the gain slider, will only affect the Red channel of your image now. You can see this by viewing the R, G and B channels separately in your viewport.

Next, attach a Transform node. Now you can expression-link, for example, the Transform1.scale node to the CCorrect1.gain node just as you would with any other expression.

Probably more ways to do this, but this is what I came up with….hope it’s what you were looking for! 😉

see ya….

[Anonymous]

You could try to isolate the red from your image and then use the CurveTool to create a curve from the average intensities from your sequence. Then link your transform to this generated curve.

Cheers,
Diogo Girondi

[Author]

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