Legacy ImageMagick Discussions Archive

If you want to duplicate color manipulation from PS in IM and there is no blurring, sharpening, convolutions, etc, only point operations, then you can use the HALD image and -hald-clut to create a 3D lookup color table in IM, the take it to PS where you apply your processing. Then bring it back to IM and apply it with -hald-clut. See http://www.imagemagick.org/Usage/color_mods/#hald-clut

Hi

How can I add the -10% constant on the the red channel in the matrix?

Kind Regards

You need a 6x6 matrix. See the example at http://www.imagemagick.org/script/comma ... lor-matrix, which subtracts 15.7%.

Thanks

Got it now

Kind Regards

There are lots of zeros because we don't normally want the green channel to be fed into the red, blue, K, or alpha channels, etc.

Ok but I dont fully understand it all:


" 1.5 0.0 0.0 0.0, 0.0, -0.157 \ - The red channel, right? The first 1.5 is the red, 0.0 & 0.0 are green and blue. But what about 0.0, 0.0, -0.157 ? (I know what -0.157 is)
0.0 1.5 0.0 0.0, 0.0, -0.157 \ The green channel, right?
0.0 0.0 1.5 0.0, 0.0, -0.157 \ The blue channel, right?
0.0 0.0 0.0 1.0, 0.0, 0.0 \ What is this?
0.0 0.0 0.0 0.0, 1.0, 0.0 \ What is this?
0.0 0.0 0.0 0.0, 0.0, 1.0" What is this?
kittens.png

The extra rows allow one to process CMYKA (and overall constant). So you need 6 rows to handle that. The first 3 permit RGB rather than CMY and the 5th row is A. Same for the columns. So you need a 6x6 matrix. The unused rows need to be there as placeholders, but they are all zero except for the row/column that is 1 to represent a no-change for that channel.

see also http://designstacks.net/color-matrix

Thank you very much for all your kind help

Kind Regards