For me the currently available (2.79) color modifiers have limited capabilities.

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To modify a HDR image which has RGB values beyond 0-1 (0-45 for eg.) I really miss an offset function which is basically adds or substracts values.

To write a pyhton script for color correction can't be very complicated I guess. I saw that there is a script node but according to the documentation it is only for plug OSL shading nodes and it is only for Cycle Renderer.

So is there a way to utilize simple math operations like +, -, /, * for color correction? Is it possible to create a color correction node without coding in C or C++?

  • $\begingroup$ The CDL works here, as does the Mix node's Add, Subtract, Multiply, and Divide. A fulcrum based contrast is a trivial divide by fulcrum, power, then multiply, for example. Also remember, "HDR" has little meaning unless referring to a display class or a file format. Scene referred values are an entire model, and not governed by ranges of values. $\endgroup$ – troy_s Jul 3 '18 at 5:22

Yes, you can use the Converter > Separate RGB and Converter > Combine RGB nodes to get access to each channel.

You get 3 streams of float values, on which you can do Converter > Math operations.

When you have build you node network, you can pack it into a Group node (CtrlG) and reuse this node in other projects (append or link from a library .blend or save the node to start-up .blend)


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