oranj wrote:There are 2 different sets of Primary colors: Light (Red, green, and blue.) and Color (Red, yellow, and blue). In light, red and green make yellow, green and blue make cyan, and red and blue make magenta. And all of those colors mixed together makes white (but this only works with light, not paint or crayons or any of that stuff. That's what the color section of this post is for.). Those are also the colors used in color printers. Now with color, (this is pretty obvious) red and yellow make orange, yellow and blue make green, and red and blue make purple/violet. Now, indigo is made with blue and purple/violet, which doesn't really fit in with the rest. So, then they had 2 choices: add all the other colors (red-orange, sunset orange, yellow-green/green-yellow, turquoise/teal, and magenta, or they could take indigo out. So they took indigo out. That means that this topic doesn't need to be here anymore, but then again, people do like to discuss things....
Totally agreed on the analysis. All I would add is the major limiter on the "rainbow" that you see is not the spectrum that it puts out, but rather the spectrum that your eyes are capable of seeing. The "visible spectrum" is exactly that. The portion of a much larger range of wavelengths that our eyes are capable of perceiving. Yes, there are two completely different schemes for color theory, Light and Surface. They behave differently in that Light is additive, and Surfaces are subtractive. (Add all 3 primary colors in light - Red, Yellow, and Blue - and you get white. Add all 3 colors in paint, and you get black.) The 3 major color schemes used for screen and print today are RGB (Red, Green Blue), CMYK (Cyan, Magenta, Yellow, Black), and HSV (Hue, Saturation, Value (Brightness)) (Lab is very rare). RGB is more accurate for Light (thus used for video output), CMYK is more accurate for Surface (thus used for professional printing), and HSV is an attempt to bridge the two worlds with an objective description of color. As for ROY G. BIV, it was an old mnemonic when I learned it, and I have no idea why those particular colors where chosen. Maybe so his last name wasn't BP.
