Airframes
Benevolens Magister
You can do both Jan. It depends how 'feathered' you want it etc. Vary the height from the mask to the surface, alter the spray nozzle, keep the brush close/further away and so on. For smaller scales, possibly even up to1/32nd scale, where the 'soft' edge was very fine, and even an airbrush won't replicate the effect, the easiest way is to mix the two colours 50/50. For example, Dark Green and Grey. Then, follow the line of the pattern, using a fine brush, 00 or maybe even 000, painting in the 'feathered' edge. Looks quite convincing old boy, what! Did it on the 1/32nd scale Spit IX conversion I posted in my selection of models a few weeks back, and I think on the Hurricane and Spit MkI. in the same post.