CMY to RGB

This set is the property of www.3drender.com

How to extract CMY channels from mattes apart from RGB with help of Nuke.
I have created a simple script using colormatrix node.

the following is the script for extracting the CMY channels

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set cut_paste_input [stack 0]
version 6.0 v1
push $cut_paste_input
Group {
name CMY
selected true
xpos -104
ypos -318
}
Input {
inputs 0
name Input1
xpos -305
ypos -203
}
Dot {
name Dot3
xpos -305
ypos -163
}
set N28350ba0 [stack 0]
Dot {
name Dot2
xpos 51
ypos 105
}
set N17e292d0 [stack 0]
ColorMatrix {
channels rgba
matrix {
{0 0 0}
{0 0 0}
{1 -2 1}
}
name ColorMatrix5
xpos 250
ypos 101
}
push $N17e292d0
ColorMatrix {
channels rgba
matrix {
{0 0 0}
{0 0 0}
{0 0 1}
}
name ColorMatrix6
xpos 17
ypos 259
}
Erode {
channels rgb
size 1.5
name Erode3
xpos 128
ypos 259
}
push $N28350ba0
Dot {
name Dot1
xpos -304
ypos 158
}
set N2849b9a0 [stack 0]
ColorMatrix {
channels rgba
matrix {
{0 0 0}
{2 -2 3}
{0 0 0}
}
name ColorMatrix2
xpos -105
ypos 154
}
push $N2849b9a0
ColorMatrix {
channels rgba
matrix {
{0 0 0}
{1 0 0}
{0 0 0}
}
name ColorMatrix1
xpos -338
ypos 325
}
Erode {
channels rgb
size 0.4
name Erode1
xpos -227
ypos 325
}
push $N28350ba0
ColorMatrix {
channels rgba
matrix {
{0 0 0}
{0 0 0}
{2 -1 -2}
}
name ColorMatrix3
xpos -54
ypos -167
}
push $N28350ba0
ColorMatrix {
channels rgba
matrix {
{1 -1 0}
{0 0 0}
{0 0 0}
}
name ColorMatrix4
xpos -287
ypos -24
}
Erode {
channels rgb
size 0.4
name Erode2
xpos -177
ypos -24
}
Constant {
inputs 0
channels rgb
format "1920 1080 0 0 1920 1080 1 HD"
name Constant1
xpos 18
ypos -136
}
Merge2 {
inputs 2+1
Bchannels none
maskChannelMask rgba.blue
invert_mask true
name Merge2
xpos -54
ypos -24
}
Merge2 {
inputs 2+1
operation screen
maskChannelMask rgba.green
invert_mask true
name Merge1
xpos -105
ypos 325
}
Merge2 {
inputs 2+1
operation screen
maskChannelMask rgba.blue
invert_mask true
name Merge3
xpos 250
ypos 325
}
Output {
name Output1
xpos 250
ypos 425
}
end_group



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copy this script and save it as .nk in notepad.
with the help of script you can convert CMY to RGB