I hate drawing cars. I'm not good at it. There's always a kid in the high school art class who earns minor fame, and maybe even a little pocket change, drawing beautifully rendered hot rods, with giant exhaust pipes roaring, tires squealing off the page, and every chrome reflection perfectly in place. He (invariably a "he" in my experience) is a venerated specialist, and he is not me.
In theory, an artist who understands perspective can draw anything. Establish a horizon line and vanishing points, and build the object out of simple shapes. It works great for a lot of things. The problem (or rather, my problem) with cars is that they're pretty complex objects, with lots of compound curves and subtle angles. Another problem with cars is that everyone is intimately familiar with them; if a drawing doesn't get the proportions just right, readers know it looks "funny" even if they can't say exactly why. Yet another problem is that every car model has dedicated owners and fans who know every bumper and bolt. I'd really like to get 'em right. .
1939 Chevy coupe, with a smaller-scale 1940 Ford on its tail
I chose the photo above, opened it in Photoshop, and made the Chevy approximately the right size to fill the hole I'd left for it in another drawing several weeks earlier.
At this point I might've traced the photo using a light box ... but I decided not to do that. Instead, I converted the color photo into a duotone image, which is like a black-and-white photo except you substitute shades of some other color for black and gray, in this case cyan.
I printed that picture onto a sheet of the same 2-ply Bristol board I use for all my cartooning. Then, I used a brush and pens to ink directly over the light blue image.
The tricky thing here is to not get bogged down in detail and draw too tightly, despite the pains I've taken to this point to be as precise as possible. Cartooning is distillation and simplification. It's got to look as loose, relaxed, and hand-drawn as the rest of the artwork that will eventually surround it. I didn't go nuts putting in lots of reflections and spotted black because, again, that wouldn't match the style of the rest of the page.
Next, I scanned the drawing into Photoshop, where I made all the blue disappear (I likewise pencil all of my artwork in light "non-photo" blue so I don't have to erase after I've inked). All that remains is my black line art, ready to copy and paste onto the open road I drew for it elsewhere.
Blue erased, ready to copy and paste
Semi-final (I may add some shadows and such later). The road texture is a charcoal rubbing I did of my concrete front porch.
I ... kinda wish I hadn't had to do that. I'd love to have the skills to dash off any car from any era from any angle, but I don't. I admit I feel a little disappointed in myself--but not much. Over time, I've come to regard both writing and drawing as primarily problem solving. I know what I want to accomplish; now what's the best way to do it? This is the best way I could think of to solve a particular problem and produce the result I wanted.