RGB to CMYK Conversion

[J]

How can I convert RGB to CMYK? I have a table with PMS and RGB numbers. Now I need to put the CMYK info in it.

Does anyone know an easy way of doing this?

J

[fishbone]

There is a formula for doing so. First you have to convert RGB to CMY. Then you convert CMY to CMYK.

RGB -> CMY

//RGB values = 0 ÷ 255

//CMY values = 0 ÷ 1

C = 1 - ( R / 255 )

M = 1 - ( G / 255 )

Y = 1 - ( B / 255 )

CMY -> CMYK

//Where CMYK and CMY values = 0 ÷ 1

var_K = 1

if ( C < var_K ) var_K = C

if ( M < var_K ) var_K = M

if ( Y < var_K ) var_K = Y

C = ( C - var_K ) / ( 1 - var_K )

M = ( M - var_K ) / ( 1 - var_K )

Y = ( Y - var_K ) / ( 1 - var_K )

K = var_K

I got this from here: Do a google search on "Color Conversion Formulas"

http://www.easyrgb.com/math.php?MATH=M13#text13

Hope this helps