Geometric shapes have always been used to teach basics of art. It is said that all objects brought down to their simplest visual levels are made up of basic geometric shapes. The airbrush, because of the soft dots of the spray, has the ability to render objects three-dimensional.

Sphere - When a sphere is rendered with an airbrush using black ink and frisket film, it ends up looking up like a black and white photograph of a ball with a three-dimensional appearance.

1. On a sheet of paper (a minimum 145lb. weight or two-ply, 50% rag content, hot or cold press, use a compass and a No. 4H pencil to draw a circle.
2. Remove the protective backing and apply the self-adhering frisket film. Smooth out any air bubbles.
3. Using a frisket knife, cut around the circle. Remember not to cut into the paper.
4. Remove the frisket film from the area to be painted (center of the circle or sphere).
   NOTE: At this point you are ready to airbrush. Let's say that the light is coming onto this sphere from the upper left-hand corner, so the highlight of the sphere will be at the top left and the dark of the shadow will be at the bottom right.
5. Load the airbrush with a pre-reduced black airbrush color (Medea Com-Art) and begin to spray it onto the surface of the paper. When you spray a shape such as a sphere, move your hand in the direction of the shape. In this case that would be an arc, so spray the paint onto the lower right-hand side and keep the upper left (the highlight) paint-free.
   NOTE: When spraying the paint onto the surface, do it in slow, overlapping movements, slowly building up the paint to the desired intensity. Let the airbrush overspray that drifts out onto the work surface develop the value changes from black to gray to white that make the sphere look rounder. Make sure that when you spray the paint, you release the trigger at the end of each pass—on/off, on/off—to avoid the barbell effect (see Part 4).
6. Once you have airbrushed the sphere to your satisfaction, gently remove the frisket film that remains on the background. You will see an exacting hard-edged line around the perimeter of the sphere where the frisket covered the white of the paper. The overspray from the airbrush came off with the frisket film, and the object that you have just painted will look like a ball. Remember, practice makes perfect!

Cube - The rendering of the cube presents a particular challenge. Unlike the sphere, which is simply one opening in the frisket, the cube has three separate planes. One key point to remember in this exercise is once you establish a hard-edged line in the darkest dark, it is virtually impossible to cover up. This statement will make more sense as you progress through the airbrushing of a cube.

1. Using a 4H pencil, draw the three planes of a cube on a sheet of paper. (With a 4H pencil you can erase—with a kneaded eraser—pencil lines that may show up in the rendering without marring the surface of the paper.)
2. Cover your drawing with a sheet of frisket film.
3. With a stencil knife and a straight edge, cut the straight lines that define the perimeter of the cube and the three lines that separate the planes. We will number these planes: right-hand #l, left-hand #2 and top #3.
4. Assume that the light is shining on this cube from the upper left-hand corner. The darkest plane will be #1, medium value plane will be #2 and the lightest plane will be #3. Remove the frisket film from plane #1. Load your airbrush with black Com-Art and spray plane #1 dark. Do it by spraying overlapping passes, slowly bringing it up to an opaqueness. Make the passes first back and forth and then up and down to get even coverage. If you begin to see wet paint puddling on the frisket film, you are spraying too much paint too quickly. Stop and let it dry.
5. Now that plane #1 is sprayed dark, remove the frisket film from plane #2. What will appear is an exacting hard-edged line that separates one plane from the other. The only way this hard-edged line can be obliterated is by painting the adjacent plane, #2, equally as dark. You don't want to do this, since it will defeat your purpose. Without re-covering plane #1, airbrush in plane #2 with slow overlapping passes, stopping when it becomes half the value of #1.
6. Now that you have planes #1 and #2 rendered, remove the frisket film covering #1. What should appear are hard-edged lines that give the shape of plane #1. This is your lightest plane and should be painted 50% of the value of plane #2. Just a few passes with the airbrush are necessary.
7. Now that all three planes have been painted dark to light, remove the remaining frisket film that covers the background. What should appear is a cube that looks very three-dimensional.

NOTE: If you wish to paint each plane a distinct color, you must replace the removed frisket film over the previously painted plane before painting the next to keep one color from drifting onto another.

Practice, practice, practice! By devoting one hour a day to practicing simple exercises, you will become proficient in airbrush technique in less time than you can imagine.