FAQ - Graphics.How to convert cmyk to rgb?
Feedback.

Answer:
The following is the code to convert cmyk values to an RGB color datatype.
It's just a basic estimate of the color values. If you are looking for completely color accurate solution, this is not it. It should work for most people. :)
Example:

Function CMYKToRGB(c as integer, m as integer, y as integer, k as integer) As color
  // converts c,m,y,k values (0-100) to color data type RGB
  // place this in a method. Supply C,M,Y,K values-
  // it returns color datatype
  
  
  dim color_RGB as color
  dim r, g, b as integer
  
  r=255-round(2.55*(c+k))
  if r<0 then
    r=0
  end if
  g=255-round(2.55*(m+k))
  if g<0 then
    g=0
  end if
  b=255-round(2.55*(y+k))
  if b<0 then
    b=0
  end if
  
  color_RGB=RGB(r,g,b)
  
  return color_RGB
  
End Function

Notes: (from the rb mailinglist)