Make sure that the mounting board is free of defects, since your photo must lie perfectly flat. At this point, it is a good idea to wash the surface of your photo with Bestene Rubber Cement Remover on a cotton ball. This will remove any fingerprint marks, dirt, grease or grime that might be on the surface of the photo print. After the print has dried, it should be sprayed using a can of matte photo lacquer finish, available at art supply and photo stores. This gives a fantastic surface to work upon that is both durable and has high adhesion, and it aids in preventing the airbrusher from disturbing the photo emulsion on the surface of the photograph.
Some photo retouching is done freehand with the airbrush, while other is done with stencils.
In most cases, however, both methods are employed. When airbrushing freehand, you spray directly onto the surface of the photo and achieve a soft, blurry paint edge. But, when working with stencils or frisket film, you achieve a hard and exacting edge. For instance if you were airbrushing around the background of a portrait's hair, you may do it freehand. Frisket film is self-adhering, but be sure it doesn't stick too tightly and do not leave it on for more than a few hours.