Your first order of business in shading is to have the figure sprayed in it's final colors and all details applied and finished. A shade effect is how to exaggerate lighting in the room so it will be the final stage of any spray. ^^These are the parts I'll be using. They are complete in detail and color application. ^^Using just ordinary masking tape again, I create a frame in which I want to shade. This keeps any excess paint off of my higher areas which would be the most likely place a light source would illuminate. ^^ Seen here, I used the airbrush to shade in heavier on the top of the panel where light would be less likely to get to. The fake light source is implied to be to the figures right side and higher up. The lower section was shaded to suggest the whole panel is sunken and rolled. The inner edge gets no paint as it's completely exposed to the "made-up" light source. ^^Expanding on the light source bit, we can highlight panel lines to accommodate this illusion. ^^ Begin by deciding where this light source will be coming from. (Try to keep it somewhat consistent throughout the figure) Now that does not mean that because the light source is up and to the right of the figure that the entire left side needs to be black. It just means try not to put your shaded areas in direct opposition. The first step here would be to lightly spray out the lower edge of this line. ^^If there are any 90 degree angles, they will need to be filled in after the first line has dried. ^^and the final product looks like this. If you so choose to go further and stay true to the light source theme, you can lightly shade the entire inner leg. The shading you've already done will darken along with it. You can stay quite light with this technique or even apply it dark so long as you stay relatively consistant you should be ok. ^^Here's a side by side comparission. ^^Here's a shaded face panel.