During my 'career' as an assistant for a graphic designer I learned how to use the airbrush. I mainly had to use it to tighten up black and white product pictures before rasterize them with a large reproduction camera.
How things have changed since then! We now use Photoshop to make pictures look better, all digital. Reproduction camera's are complete history. Nowadays you scan your drawings with your own affordable all-in-one printer, make them look sharper and more colourful using Photoshop and publish them on your own weblog for all the world to see.