[fexii]

Gradient is when one color smoothly blends into another by putting many similar colors in between. Usually its done by a program, such as using a paintbrush vs. a pencil tool. It's mainly frowned upon in the pixel art community.

Dithering is also one color blending into another, but its done with only two colors. The trick is to put the blended color every other pixel to create the illusion of mixing. It's hard to describe but it should be very easy to find out what I'm talking about. I used a bit of it on the upper portion of the wings in my signature, but there's much better examples elsewhere. The advantage of dithering is that it saves colors and makes smaller file sizes.