Actually, we're all right in this case (although, that first information I had on additive and subtractive colours was innacurate). The difference in CMYK and RGB is the way the colours are produced. This is from one of the sights below:
Quote: "Additive color emanates directly from a light source. Subtractive color comes from light which is relfected off of an object from a light source. Because additive color comes to our eyes directly (unless it is filtered), it is purer color."
The other side of the coin, though, is that there are colours in the CMYK which cannot be produced with RGB methods.
By the way...K is for black, so as not to be confused with blue.
Here are some links for more reading:
http://www.sparklenet.com/1_Main_Street/Art_Smarts/Color/Nature/CMYK_vs_RGB.htm
http://marvin.mrtoads.com/rgb_vs_cmyk.html
http://dx.sheridan.com/advisor/cmyk_color.html
And try these searches in google (without the quotes):
"cmyk rgb color space"
"cmyk vs rgb"
"cmyk rgb color space conversion"
BTW, the most common spelling of "colour" seems to be "color" because of those yankees to the south of me. You can try either-or when doing searches.
Thanks all...this topic has been colourful! (every once of pun intended).
-= i only do what my rice krispies tell me to do =-