What are these "browser-safe colors" and should I care?

Older 8-bit monitors display only 256 colors at a time (16 X 16 or 28)

Browsers do the best they can to reduce the number of colors in your picture to accommodate older monitors.

Some colors get shifted to the nearest available color. The rest get dithered to approximate the original.

The results are, um, mixed.

Furthermore, browsers on older Macintosh computers use a different palette from those on older Windows computers.

So the "browser-safe" palette, or CLUT (Color LookUp Table) was born. It contains just the 216 (6 X 6 X 6) colors that are common to browsers on Macs and PCs.

And we're not going to mention that Unix uses a different set...

See it here, courtesy of Alan Barasch.

Should we worry?

Most current monitors and browsers show "true color" or millions of colors (256 X 256 X 256 or 224)

So, no.

Depending on who your target audience is, some of your viewers may have older equipment. Or use the latest handheld gizmos, but with 8-bit color. Or play 8-bit computer games. Or surf the net on their Dick Tracy watches.

So, yes.

Sometimes