Overview Matt acrylic colours and water-based are specially formulated for airbrushing. The Model Air colour range contains the most complete selection of the military colours used in recent history, including the colours of WWI, WWII and up to the present. Each colour is based on extensive research by our experts of the existing and previous military references so as to offer the modeller the highest possible historical accuracy. Model Air is used directly or diluted with Vallejo Airbrush Thinner or Flow Improver. It is recommended to first prime the surface, and then apply Model Air in several layers. The colours dry very rapidly and form a homogenous paint film of extraordinary resistance while preserving even the smallest detail of the model. For airbrushing these colours, the compressor air pressure is recommended at 15 – 20 PSI or 0.5 to 1 kg. Model Air can of course also be applied with a brush. Model Air is not flammable and does not contain solvents.