The reason that color charts are necessary, is that frequently you want to be able to match a color precisely to that of one that will be shown by most web browsers as a background, text, or table cell color. Many older browsers and those running on computers with either poor quality graphics cards, or bad display settings may only show the basic 256 colors (or less) and just dither any unusual ones to the closest standard color. The gradual fading of color on Webdisplays site backgrounds will appear "blocky" on these browsers. This would actually cause an 'isobaric' effect on curved flesh tones (like a weather map). Even 16 thousand colors is not as good as millions of them!

This is the reason why, even though you may know the color value number, the color in your JPG image does not match the one seen in your HTML document/browser. To make it more complicated, this doesn't always affect backgrounds, or text, which can use the full available pallet of the display. Also many people use the largest screen size (finest resolution) available, with the fastest refresh rate (to reduce flickering) which reduces the number of colors they can display. Users with WebTV cannot fix this hardware problem at all. Some older browsers, like AOL/IE3 are badly crippled and incapable of more than 256 colors.

HTML colors are represented by a number that is broken into 3 sections. For instance the HTML color #9933CC shows purple because it contains #99 red #33 green and #CC blue. In the 256 color pallet, numbers are "counted" in hexadecimal format, so the numbering runs in this sequence:

0,1,2,3,4,5,6,7,8,9,A,B,C,D,E,F

Letters are used for numbers above 9! Only the paired values using only these numbers:

0,3,6,9,C,F (as: 00,33,66,99,CC,FF),

are actually displayed whenever colors are mixed, so the color #317697 (kingfisher blue) could be shown as #336699 which is bit stronger.

If you know how to mix colors in your head, you can compose them on the fly using these rules. Upper or lower case letters do not matter, and the numerical values in between are only used in pairs for a single color (#550000 or #EE0000 for any darker or brighter reds) or in sextets as #444444 or #AAAAAA for any darker or lighter grays. They are always combined in three-paired (just paired values above) sets like #CC6633 or #66CC33 or#3366CC.

Click here for the standard HTML 256 Color Chart Image and you can see what I meant!

Wbebdisplays simple color picker...