Color channel mover - script

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Color channel mover - script

A piece of code to put in the reactor-script node.

It can be used to move the color-channels individually up or down. It's simple addition or subtraction to the pixel-value.

It can be used for balancing film-negatives (the orange mask), for whitebalancing ordinary images, or you can turn black'n'white images into colortones like sepia or blue.

Code: Select all
`//Increase brightness//##NAME:Andy's Gudermannian brightness code//##DESCRIPTION:Andy's Gudermannian brightness code modified by JEL for the PR script-block.//##INPUTS:1//##VAR1:50//##VAR1_NAME:Gain LUMA//##VAR2:1//##VAR2_NAME:Gain factor//##VAR3:50//##VAR3_NAME:Gain RED//##VAR4:50//##VAR4_NAME:Gain GREEN//##VAR5:50//##VAR5_NAME:Gain BLUEvoid main(){   // get the image from input socket   image img(INPUT);     int width = img.width;   int height = img.height;   double gainCenter = -50 * VAR2;      for (int y=0; y<height; y++)   {      for (int x=0; x<width; x++)      {         // one way to get color from pixel         pixel color = img.Pixel(x,y);         double rr;         double gg;         double bb;//         double rr = color.r^2.2;//         double gg = color.g^2.2;//         double bb = color.b^2.2;         rr = color.r + (gainCenter + (VAR1 * VAR2)) + (gainCenter + (VAR3 * VAR2));         gg = color.g + (gainCenter + (VAR1 * VAR2)) + (gainCenter + (VAR4 * VAR2));         bb = color.b + (gainCenter + (VAR1 * VAR2)) + (gainCenter + (VAR5 * VAR2));//         rr = color.r^0.45;//         gg = color.g^0.45;//         bb = color.b^0.45;         img.SetRGB(x, y,rr,gg,bb);      }      }      // send the image to output   img.SetOutput();   }`
DAP (AOPs): http://jelstudio.dk/DAP/
PhotoReactor (flows, effects and scripts): http://jelstudio.dk/PhotoReactor/
JEL

Posts: 294
Joined: Fri Jan 06, 2012 9:35 pm

Re: Color channel mover - script

You know that There are some dither methods for color reduction, do you have any idea for better algorithm that can generate with very low colors?
Thank you
smmsamm

Posts: 319
Joined: Tue Oct 26, 2010 7:58 pm

Re: Color channel mover - script

This script doesn't do color-reduction. It moves, or slides if you will, the color-channel up or down (on the histogram it looks like it's sliding left or right)

The purpose is to align the RGB channels manually.

If you have a scanned film-negative, with the orange-mask still included, the RGB channels will be misaligned. This script can be used to align them.
Or you can intentionally misalign the channels on a normal image, to create special effects or to whitebalance the image in a specific place on the histogram.
DAP (AOPs): http://jelstudio.dk/DAP/
PhotoReactor (flows, effects and scripts): http://jelstudio.dk/PhotoReactor/
JEL

Posts: 294
Joined: Fri Jan 06, 2012 9:35 pm