While not weathering, accentuating the shadows of a model goes a long way into making it look realistic. Usually this is accomplished with a dark wash. Washes are notoriously difficult to apply with success, I have developed an alternative, however. Apply an overall of base of the shadow colour, use a complimentary to the final base colour, such as dark brown for dark yellow, dark olive drab for dark green and so on. Now, with an airbrush, apply several thin coats of the final base. Note how the darker colour will stay in the crevices and rivet holes. Practice is important with for this effect to be completely successful.
Due to many hours of exposure to the sun's UV radiation the paint will lighten and in extreme cases bleach and completely flake off. This is most obvious in tropical and desert regions and well as the Steppes on Russia. These effects are more pronounced in the Summer months, so checking references as to time of year and location is important. For simple everyday fading add about 10% (by volume) of white to the base colour and gently apply a fog coat to the upper surfaces of the model. For extreme fading, such as for vehicles used in the desert, scrub into the paint some ground up white chalk dust using a stiff short bristled paint brush (be careful not to break any pieces on the model). For those who use Tamiya paints, add about 20% Flat base and 10% flat white thinned by 20% and gently fog this mixture over the model. The results with Tamiya paints are incredibly realistic.
Winter White Wash
Usually in snow conditions AFVs are camouflaged in white. This was, in the case of the Germans in WW2, a water based lime/salt mixture which was easily washed off with water. Mostly this was brushed on with paintbrushes, mops, brooms, rags and even thrown on direct from the bucket! The best method for simulating this is with white artist's tube water colour paint, thinned out and applied with a brush which best matches the prototype pattern. Occasionally an air-gun was used. To simulate this, thin the mixture further and apply with the finest setting on an airbrush. The key to realistic results with an airbrush is to gradually build up the finish, leaving bare and thin patches. The reason I prefer a water soluble paint is to facilitate the weathering process. To simulate areas of wear the paint can be rubbed off using a slightly moistened Q-Tip. For scratches a moist tooth pick can be used. Experimentation and practice with wearing off white wash paint is very important as it very easy to goof and end up with a terrible looking model.
Water Based Secondary Camouflage
For field applied, brushed on secondary camouflage (such as the dark green/red brown schemes used by the German Panzer forces in WW2,) it is often better to use water colour paints to depict this. Not acrylic model paints but artist's tube water colours. Suitably thinned and brushed on, these paints, due to their inherent translucent qualities, look chalky and faded just like the real thing.
It is important to seal the two former cases, as further weathering with water-based paints will destroy them. However, most enamel and lacquer based sealers will obliterate the subtle effects rendered with the unique qualities of the paints used, so it is important to test first.
Simulating worn paint realistically requires advanced planning: worn paint is just that -- the paint has been worn off revealing the bare metal and primer underneath. So before the base colour is applied, these areas must first be painted in bare metal and primer colours. Referring to figure 1, a typical worn area consists of -- from center out -- bare metal, rusty metal, primer and the unworn base paint. To achieve this, follow these steps:
- Paint the area to show wear with a shiny metal colour (use whatever your favourite is). Mask the section that is to remain shiny metal with a liquid masking agent.
- Paint the area with rusty metal next (do not remove the mask covering the paint below). Mask over this again, leaving a rim of rusty metal around the shiny metal.
- Repeat step 2 for the primer colour. For WW2 German AFVs this should be Red-Oxide, (I do not know what colour primers where used by other nationalities at this time).
- Finally apply the base colour. Let dry and remove all the masking (three layers).