Primary Colors

The standard HTML 4.0 color names for the primary colors (also called the color primaries) are (from http://www.w3.org/TR/REC-html40/types.html#h-6.5 ):

Primary additive colors (commonly known as "RGB" red, green, blue, the standard names are "Red","Lime","Blue")

"#000000" = "Black"	"Black" = "#000000" start here and successively add more
"#FF0000" = "Red"	"Red" = "#FF0000"
"#00FF00" = "Lime"	"Lime" = "#00FF00" (often called green)
"#0000FF" = "Blue"	"Blue" = "#0000FF"

Primary subtractive colors (commonly known as "CMYK" cyan, magenta, yellow, black, the standard names are "Aqua", "Fuchsia", "Yellow", "Black" )

"#FFFFFF" = "White"	"White" = "#FFFFFF" start here and successively mix in
"#00FFFF" = "Aqua"	"Aqua" = "#00FFFF" (often called cyan)(often incorrectly called 'blue')
"#FF00FF" = "Fuchsia"	"Fuchsia" = "#FF00FF" (often called magenta)(often called purple)(occasionally called pink)
"#FFFF00" = "Yellow"	"Yellow" = "#FFFF00"

Every color visible to the human eye can be referenced by 3 coordinates. There are 2 common coordinate systems.

The "RGB" coordinate system starts with black, then adds measured amounts of "Red", "Lime", and "Blue". Adding the maximum amounts off all three colors gives white.

The "CMYK" coordinate system starts with white, then adds measured amounts of "Aqua", "Fuchsia", and "Yellow". In theory, adding the maximum amounts of all three colors should give black, but the inks commonly used usually create merely a dark muddy brown, so pure "Black" ink is also used to give crisp images.

Related links

• A perfectly smooth color wheel http://www.alphabet.com/color/wheels/index.html emphasizes the fact that there are not a certain finite number of discrete colors, but a continuum between the primary colors. Two colors have to be "different enough" for the human eye to see the difference. (I've been told that different human cultures not only give different names to the same color, but actually divide up this continuous spectrum differently, into more or fewer colors).
• "Through the 6x6x6 Color Cube: An Interactive Voyage" by William I. Johnston http://world.std.com/~wij/color/ has a really nice series of images viewing the 216 color "browser-safe palette".
• The test file at http://www.cs.wisc.edu/~ghost/gsview/netscape.html uses "Cyan, Pink, Yellow, Black" for CMYK, and "Red, Green, Blue" for RGB on the color wheel. Whatever happened to Magenta ?
• http://articles.scrapbooking.com/colorwheel.htm
• Browser-safe Color Palette by Hue. http://www.primenet.com/~thoward/clrs_hue.html
• (most) Humans see 3 primary colors. Most machines are colorblind, seeing only shades of gray. However, satellite photographs often have 5 primary colors, and a few machines (gas chromatographs) see a practically infinite number of primary colors. See machine_vision.html for more on machine vision.
• Map Makers Can Avoid Confusing The Color Blind http://www.sciencedaily.com/releases/2000/04/000428082212.htm | http://www.psu.edu/ur/2000/colorblindness.html
• ColorBrewer by Cindy Brewer and Mark Harrower http://www.personal.psu.edu/faculty/c/a/cab38/ColorBrewerBeta.html ``an online tool designed to help people select good color schemes for maps and other graphics.''
• "color vision and art" "causes of color" http://webexhibits.org/

Started 1998 Jan 08; updated 2001-02-14

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