The colours have been very carefully chosen to provide the model-painter with the references most frequently employed. Tests have been carried out for over two years to develop the tonalities which correspond to the RLM, RAL and FEDERAL STANDARD colours commonly used. Model Air adheres exceptionally well to all surfaces. The adhesion of Model Air to resin models, plastics, steel and white metal is extraordinary. The pigments used for airbrush colours need to be ground to the finest possible consistency to avoid obstruction of the airbrush valves. The revolutionary milling process of the pigments used in the Model Air formula gives the model-painter technical assurance and finest texture when applying the colours to the model, and produces a very superior quality when applying the colours with a brush for miniscule details, for washes and transparencies and layered application of diluted glazes. However, to avoid problem due to dried acrylic resin inside the airbrush valve, please check Â“ Technical Information Â” for more details about Varnishes, Thinners, and general application.