Thought you all might like to see what I do for work. Need 400 units weathered? Here's how.
I use a trusty Paasche H airbrush for the detail work & a Paasche detail gun for base grime. In this pic, I'm just dong one wash of dark grey-green. Some cars can have as many as 4 color washes & masking blockouts. After I get done with them, many will go to a 4 color process printer to get "tagged" with graffiti. We work in "N" & "Z" scale cars & locomotives.
Reid