colours

[iGuest 3]

I've always used RGB colours (e.g #000000)^which is really easy to work out what a colour will look like from the numbers...how does hex work, and where is hex best used?

[iGuest 3]

hex is base 16 instead of base 101 = 12 = 2.......A = 10B = 11C = 12D = 13E = 14F = 15To count in Hex: 00 01 02 03 04 05 06 07 08 09 0A 0B 0C 0D 0E 0F - 10 11 12 13 14 15 16 17 18 19 1A 1B 1C 1D 1E 1F etc...it is in factors of 16 and always has two digits 0f=15 1f=29

[iGuest 3]

This is the standard for Color in Cascading Style Sheets from w3.org

6.3    Color units
A color is a either a keyword or a numerical RGB specification.

The suggested list of keyword color names is: aqua, black, blue, fuchsia, gray, green, lime, maroon, navy, olive, purple, red, silver, teal, white, and yellow. These 16 colors are taken from the Windows VGA palette, and their RGB values are not defined in this specification.

BODY {color: black; background: white }
H1 { color: maroon }
H2 { color: olive }

The RGB color model is being used in numerical color specifications. These examples all specify the same color:

EM { color: #f00 }              /* #rgb */
EM { color: #ff0000 }          /* #rrggbb */
EM { color: rgb(255,0,0) }      /* integer range 0 - 255 */
EM { color: rgb(100%, 0%, 0%) } /* float range 0.0% - 100.0% */

The format of an RGB value in hexadecimal notation is a '#' immediately followed by either three or six hexadecimal characters. The three-digit RGB notation (#rgb) is converted into six-digit form (#rrggbb) by replicating digits, not by adding zeros. For example, #fb0 expands to #ffbb00. This makes sure that white (#ffffff) can be specified with the short notation (#fff) and removes any dependencies on the color depth of the display.

The format of an RGB value in the functional notation is 'rgb(' followed by a comma-separated list of three numerical values (either three integer values in the range of 0-255, or three percentage values in the range of 0.0% to 100.0%) followed by ')'. Whitespace characters are allowed around the numerical values.

Values outside the numerical ranges should be clipped. The three rules below are therefore equivalent:

EM { color: rgb(255,0,0) }      /* integer range 0 - 255 */
EM { color: rgb(300,0,0) }      /* clipped to 255 */
EM { color: rgb(110%, 0%, 0%) }  /* clipped to 100% */

RGB colors are specified in the sRGB color space [9]