OK, CEL shading is a long process. It takes a very long time to get it right. I'll use the pic that esperunit posted for examples. 1) Notice that the headlights are real, they are not shaded, those are actual headlamps. As are the wheels. And the background. This is done by layering. The cell shading is done on a different layer than the actual picture. The best way I have found to do this is to create a layer and set the opacity to 50% so you can see through it. You will want to revert to 100% opacity at times to check color and coverage. 2) First thing you want to do is to outline the entire vehicle with the line tool in black. You will do this on the layer you created. This takes time. Hours sometimes. Like in the picture above, you wanna nail down all the details. 3) Once you have the black outlines how you want them, you will convert the layer from vector to raster. THe line tool draws in vector format and will not work with any of the standard tools. 4) Now that you have rasterized your shape, you can start coloring it in. Select a color that best matches the car's real color. Notice above how he used lighter colors for brighter panels, and darker colors for panels exposed to less light. Each panel should be one color. You should not be blending or shading your colors. This is where the term CEL shading comes from...each cell of the object has a color that best describes it's relative brightness. 5) Remember the headlights and such that are real? We will work on that now. With your special layer at 100% opacity, pull out that eraser tool. Now simply 'wipe off' the color that was placed over things that you want to show. If you painted the headlights black, you can erase teh black off of them and show the real life image of the headlightss beneath. Also, if you wanted, you could simply not paint over them. Lots of ways to go about doing this. More later...after I see some of the above techniques used.
