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trevlac · 14th April 2004, 15:12

I wanted to say, mf's approach is very creative. It isolates positive V values and then reduces them. (Unlike Tweak and ColorYUV, which reduce all of V or all of V&U). You can even target high red by adjusting the levels parms, and not really effect magenta.

But honestly, figuring out how to do this is a bit of a pain.

Prompted by this, and my own problem of oversaturated reds, I used Tweak as a starting point and made a plugin with the added ability to target a specifice hue range and/or a specific saturation range. This is all done in the YUV colorspace.

For example, on unscaled U&V, exact red is at 109 degrees. To cover the a range from one of the 6 primary and complimentary colors, go out +/- 30 degrees. So 'red' hue goes from about 140 to 80 degrees. YUV can go beyond then nominal range of 16-240. 0-255 actually covers a 113.5% range. Anything above 75% red is probably too high. So target red from 115% to 75% and reduce its saturation from 1.00 to 0.75.

This is the syntax to do the above and reduce the saturation of red highs.

TweakColor(sat=0.75,startHue=80,endHue=140,maxSat=115,minSat=75)

Here is the thread with the plugin link

http://forum.doom9.org/showthread.php?s=&threadid=74334

14th April 2004, 15:12	#17 \| Link
trevlac budala Join Date: Oct 2003 Location: U.S. Posts: 545	I wanted to say, mf's approach is very creative. It isolates positive V values and then reduces them. (Unlike Tweak and ColorYUV, which reduce all of V or all of V&U). You can even target high red by adjusting the levels parms, and not really effect magenta. But honestly, figuring out how to do this is a bit of a pain. Prompted by this, and my own problem of oversaturated reds, I used Tweak as a starting point and made a plugin with the added ability to target a specifice hue range and/or a specific saturation range. This is all done in the YUV colorspace. For example, on unscaled U&V, exact red is at 109 degrees. To cover the a range from one of the 6 primary and complimentary colors, go out +/- 30 degrees. So 'red' hue goes from about 140 to 80 degrees. YUV can go beyond then nominal range of 16-240. 0-255 actually covers a 113.5% range. Anything above 75% red is probably too high. So target red from 115% to 75% and reduce its saturation from 1.00 to 0.75. This is the syntax to do the above and reduce the saturation of red highs. TweakColor(sat=0.75,startHue=80,endHue=140,maxSat=115,minSat=75) Here is the thread with the plugin link http://forum.doom9.org/showthread.php?s=&threadid=74334