CMYK color

[James D Jarvis]

CMYK or process color is the model used in print. I spent years doing print work and just find it easier to mix colors using that color model. 
Each color is expressed as a % of Cyan C, Magenta M, Yellow Y, and Black K
White is 0,0,0,0
Red is 0,100,80,0 to 0,100,100,0
Greys are 0,0,0,1 to 99   or C,M & Y set to the same value from 1 to 99

Code: (Select All)

Screen _NewImage(640, 480, 32)
Color _RGB32(0, 0, 0), _RGB32(255, 255, 255)
Cls
'a simple demo of the color values
Do
    Print "Enter C,M,Y,K"
    Input c, m, y, k

    k& = cmyk~&(c, m, y, k)

    Line (200, 200)-(400, 400), k&, BF
Loop Until c = -100


Function cmyk~& (c As Long, m As Long, y As Long, k As Long)
    ' CMYK process color Cyan, Magenta, Yellow, Black each  expressed as a percent from 0 to 100
    r = 255 * (100 - c)
    r = (r / 100) * ((100 - k) / 100)
    g = 255 * (100 - m)
    g = (g / 100) * ((100 - k) / 100)
    b = 255 * (100 - y)
    b = (b / 100) * ((100 - k) / 100)
    cmyk~& = _RGB32(r, g, b)
End Function