Graphics

RGB Color Values

Using RGB / HEX Values in HTML

When discussing computer graphics, the term RGB is shorthand way of saying an image uses the Red/Green/Blue Color Model.

There are many ways to describe color in mathematical terms.  The basic idea is to assign a value to the proportion of each color in the definition.   In the RGB model used in HTML markup, the colors are represented by three hexideicimal pairs, each denoting a value of 0 to 255 for each of the R, G, and B values of a given color.

COLOR	Hex Equiv.	R	G	B
Pure Red	#FF0000	255	0	0
Pure Green	#00FF00	0	255	0
Pure Blue	#0000FF	0	0	255
50% Red	#800000	127	0	0
50% Green	#008000	0	127	0
50% Blue	#000080	0	0	127
Black	#000000	0	0	0
White	#FFFFFF	255	255	255

Since each color has a range of 0 through 255, (a total of 256 "values" including "0"), you can multiply 256 x 256 x 256 to get a total of 16,777,216 (colors).

This is why hardware or software is commonly described with capability of "16 Million Colors", which simply means it can display "RGB".

Another way to reference colors in HTML is to simply use the name of the color.

Many basic color names will work, including the traditional colors of the rainbow, (Red, Orange, Yellow, Green, Blue, Indigo and Violet).

Here's ole Roy G. Biv, (the name is a way to remember the colors of the rainbow; "R" is for Red, "O" is for Orange, and so on)...

Red #FF0000

Orange #FFA500

Yellow #FFFF00

Green #008000

Blue #0000FF

Indigo #4B0082

Violet #EE82EE

If you see the seven different colors, (below), and they appear exactly as the colors in the rainbow above, (which uses RGB values in the code), then your browser correctly interprets colors by name when used in HTML.

Red

Orange

Yellow

Green

Blue

Indigo

Violet

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