HTML Colors

1. Color Values
   1. Hex triplet
   2. 16 Million Colors
   3. HTML Color Names
2. Web Safe Colors
3. Shades of Gray
4. Safe Shades of Gray

Color Values

HTML colors are defined using a hexadecimal notation (HEX) for the combination of Red, Green, and Blue color values (RGB). Those HEX values are specified as 3 pairs of two-digit numbers, starting with a # sign. Being the lowest value that can be given to one of the light sources 0 (in HEX: 00). And the highest value 255 (in HEX: FF).

In the table below you can see the final result on turning on (HEX: FF) and off (HEX: 00) each of these values.

RGB compound colors #000000 #FF0000 #00FF00 #0000FF #FFFF00 #00FFFF #FF00FF #FFFFFF

The Additive color model

Hex triplet

A hex triplet is a six-digit, three-byte hexadecimal number used to represent the red, green and blue components of the RGB color system in HTML, CSS, and other applications.

Each byte the least (00) to the most (FF) intensity of each of the color components, in the following order:

• Byte 1: red value (color type red)
• Byte 2: green value (color type green)
• Byte 3: blue value (color type blue)

For example, considering the color where the red/green/blue hexadecimal values are 86, 42 and BA respectively. The hex triplet is obtained by concatenating those digits together, "8642BA" in this example.

Note that if any one of the three color values is less than 10 (hex), it must be represented with a leading zero so that the triplet always has exactly six digits.

For example, the hexadecimal triplet A2, 9, C, would be represented by A2090C.

16 Million Colors

The number of colors that can be represented by the "Hex triplet" system is:

256 x 256 x 256 = 16,777,216

HTML Color Names

The World Wide Web Consortium (W3C) has listed, in the HTML 4.01 specification, 16 valid named (case-insensitive) colors for HTML and CSS, as follows:

There are a few more non W3C web standard color names, but since different browsers may display different colors for the same color name, as a rule of thumb, avoid using them.

To achieve the same result in all browsers, always use the Hex triplet notation.

Web Safe Colors

Some years ago, when computers supported max 256 different colors, a list of 216 "Web Safe Colors" was suggested as a Web standard, reserving 40 fixed system colors.

The 216 cross-browser color palette was created to ensure that all computers would display the colors correctly when running a 256 color palette.

This is not important now, since most computers can display millions of different colors. Anyway here is the list:

Keep in mind however, that many companies that hire designers and developers still feel it's a badge of Web design honor to work with these colors, so you might want to know how to use them if you have to.

Really Safe web colors

Some of the above colors fits nice in 8-bit color displays which were much more common when the 216-color palette was developed than they are now.

David Lehn and Hadley Stern discovered that only 22 of the 216 colors in the web-safe palette are consistent reliably displayed remapping on 16-bit computer displays. They called these 22 colors the "really safe" palette, in the table above, the "really safe" colors are *underlined*.

Shades of Gray

Gray colors are, in general, created by using an equal amount of power to each of the RGB colors.

In the table below you can see all the "official" shades of gray.

Safe Shades of Gray

Unfortunately not all of the Shades of gray are safe and will be correctly displayed in all environments.

So, considering the "Safe Web Colors" listed above, here is the "Safe Shades of Gray" list.

Which is a very limited one.