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View Full Version : How to apply a gamma adjustment to a color?



JeffrySG
09-30-2009, 10:26 AM
Is there a way with nodes to apply a specific gamma adjustment to any of these?

A RGB color?
A single Scaler value?
An image?

I'm trying to set up a node so you can pick your normal colors onscreen and have the node adjust for a linear workflow. Essentially I am looking to apply a 0.45 gamma adjustment to a RGB color and it would be nice to be able to do this to an image as well if needed.

What I was planning to do was to have my RGB color - break it into the separate RGB components (with Mike's Channel Blender Node) - apply the gamma correction of 0.45 - then send those values back into a single RGB color (Make Color Node) - then into the color input.

I'm just getting stuck on applying a mathematical gamma adjustment.
Thanks for any ideas. :)

PS. I was planning on sharing the final result with everyone too.

jameswillmott
09-30-2009, 10:27 AM
Use the Wrap and Gamma function nodes together to apply gamma to each channel in turn.

JeffrySG
09-30-2009, 10:37 AM
Use the Wrap and Gamma function nodes together to apply gamma to each channel in turn.

Thanks James!

Not sure why but I missed that entire Functions menu of nodes. Not like I would have know to use the Wrap node anyway. Doh! ;)

:D

JeffrySG
09-30-2009, 11:09 AM
Thanks again... I was able to do what I needed... Here's the node if you'd like to see or use.

http://www.newtek.com/forums/showpost.php?p=931713&postcount=20

Axis3d
11-13-2009, 08:43 PM
Download the Jovian Color Picker (http://www.joviancolorpicker.com/).

If you pay the 25 bucks (well worth it), it unlocks a tab in the color picker that enables gamma correction (which I set to 2.2). You are able to pick the colors you want, but the returned color sent to LW is gamma corrected. I use it in our film workflow now.

probiner
11-13-2009, 09:01 PM
Thanks again... I was able to do what I needed... Here's the node if you'd like to see or use.

http://www.newtek.com/forums/showpost.php?p=931713&postcount=20

Last wrap doens't have the function tied to it on purpose?

Tobian
11-13-2009, 10:25 PM
If you're using the DB&W tools, why not just use the simple colour corrector tool, which has gamma correction in it, and save 20 odd nodes? :D

You can also do all that by splitting the nodes into 3 chanels, then applying a POW (scalar maths) value of 2.2 (which works in the inverse exponent, so that's like applying a 0.45 gamma) so you can avoid having to use external plugin nodes, if you so wish! :D

rsfd
11-22-2009, 08:32 AM
You can also do all that by splitting the nodes into 3 chanels...so you can avoid having to use external plugin nodes...

Thanks again, Tobian
you gave me the needed hint.

(for Mac-64x-OB, until Mike's tools arrive in 64x flavour).