Whats the name of the effect...

[Latifa]

Whats the name of the effect that generalises colours, so for example someones brown hair, made up of millions of different shades of brown could be turned into a monotone brown. I don't want to look through 500 odd effects looking for it.

[NovelGentry]

If it's an indexed image you could just decrease the pallette and repaint any spots that screwed up. I'm not sure under what program you're talking about here. Sounds like a mean way to vectorize images though.

[Floyd.]

Posterize?

[encephalon]

yeah, posterization should do the trick.. although you could also simply use a dithering althoritm as well (which is how it goes to indexed color).