Airbrushing Preparation

• Check that the paint you're using is appropriate for the model's materials. Some plastics used by modelers require that you use specific paints for proper application. Thin your paints to a consistency just slightly less than that of milk for use. The thinned paint should be just about opaque.
  
  Before working on your model you should tape off the boundary edges of the area you'll be painting. Use drafting or automotive quality masking tape for edging in order to avoid leaving a gummy residue behind when the tape is removed after painting.
  
  

Paint Application

• Keep your airbrush parallel to the spraying surface. Avoid spraying the model at an, as this will tend to get paint beneath the taped areas. When you spray, begin the paint application just before the area you wish to spray on, continuing to apply the paint with an even stroke until right past the area. Apply the paint in light coats, layering the coats until you get a complete covering of paint.
  
  Begin the painting process with a coat of primer. Airbrushes were developed in order to apply ink to paper. The primer coat will create a textured surface that prevents the paint from running while being applied. Prime your model with black paint as colors applied later will show a sense of depth and shadows due to the black paint subtly showing through.
  
  Hold your airbrush about 6 in. from the model surface for best results on wide areas. If your airbrush is too far from the surface the paint begins to dry before hitting and will clump producing a gritty surface, too close and you'll create layers that are too thick, which tends to result in running paint and streaks. Move the brush to 1 in. or less from the surface when working on fine details, taking care to apply smoothly to avoid runs. For up-close work, you'll also want to apply the paint in light coats that require several layers to finish.
  
  Apply multiple layers consisting of different colors to achieve subtle color mixes. This is a good technique for achieving custom color combinations that change according to the angle the model is viewed from. Remove the cap from the airbrush to expose the spray needle for finer detail work. Without the cap the airbrush will give much finer lines on application. Applying an extremely thin coat of paint can be used for stark shading purposes on areas such as panel lines. The mix for this shading should be translucent, and will require multiple applications to leave visible lines.
  
  

Practice

• These techniques won't make you an airbrushing expert overnight. Like any art form, it requires practice to gain any proficiency. Purchase some butcher's paper to practice the techniques on before applying them to your model, and soon you'll be getting good results.