When weathering rolling stock what is the difference between air brushing a coat of light grey or white to fade down the paint or just hitting it with dull coat? Six of one, half dozen of the other?
Dullcote is nothing more than clear paint and has no solid color pigments that light gray or white paint has. Dullcote will fade any surface to a very slight degree, but the result is hardly noticeable. The paint when sprayed in a very thin amount will give the result of faded paint by covering it.
Someone more knowledgeable can correct me on this but I always thought that Dullcote gives a flat finish to otherwise glossy paint. Once that is done then you can add weathering such as fading, dirt, grime, rust, etc.
Although Dullcoat is clear lacquer, you can use it to fade rolling stock if you wet it with isopropyl after it dries. It creates sort of a milky haze and the effect works well on black and other dark colors, but its not as even as with airbrushing.