I did this for a client last year. All freehand with the exception of the Balinese Temple silhouette. I use a number of different airbrushes as they have they're own unique features, so on this I used a Badger Anthem, and a Renegade for detail. Colours came in the way of Acrylic Lacquer, Water based acrylics.... Comart, Createx and diluted screen printing inks. All work is done directly on the pre shaped foam blank, then it is fibreglassed in the usual way.