Web Safe Colors
Web safe colors are colors that belong to a color palette that was designed to be "web safe". The web safe palette is not as relevant as it once was, due to the advancement of technology, however, it's still played a significant part in the development of the web.
What is Web Safe
In this context, the term "web safe" simply refers to colors that will look the same on any computer. When writing HTML, web developers can choose any color they like using the hex color codes, but in the early days of the web, most of these colors would look different, depending on the computer that the website visitor was using. Back in the early days of the web, most computers could only display 256 colors. Some could display more but, most colors looked different, depending on which computer you were viewing it on. Many web designers were horrified when they found out what their slick and colorful website looked like in another browser or operating system. Often, the colors would dither and basically look really bad.
That's why the web safe color palette was created. To ensure that when a web designer established the color scheme for a website, that those colors would look the same on all browsers and operating systems.
Why Only 216 Colors?
The web safe color palette contains 216 colors. Back in the early days of the web, most computers only had 8-bit video cards. Therefore, they could only view 256 colors. Out of those 256 colors, 40 of them looked different between Macs and PCs. The reason that the web safe color palette only has 216 colors is because of those 40 colors. Limiting the palette to 216 ensures that both Macs and PCs display all colors the same.
Web safe color palette is/was also referred to as browser-safe palette, Netscape palette, 216 palette, web palette, and the 6x6x6 color cube.
Web Safe Color Palette
If you prefer to use only web safe colors in your color scheme, here's the web safe palette.