Practical approach to color
Thinking about color can be daunting and I feel that it helps to start with gray. Study gray all fucking day is what I say. So we're going to work up some images with a gray underdrawing. Bust out yer gray Prismacolor markers or gray colored pencils.
The mental process of printmaking and painting - of layering tone and value to achieve depth, lets me compose "in color" even when it's just black - which, of course, is a color. I'm not speaking of adding gray tones after the image is complete - but within the process of drawing itself - tone layering and weaving together with lines.
Until recently full color printing has been prohibitively expensive to produce. I'd say most cartoonists "think in black and white" largely because the color process has always actually been a separate process. There was no inexpensive way to photograph and print a comic made in color - meaning the original art was full color - until about the 1980s. And the quality was terrible - like bad color xerox machines from 1983. So the actual process of creating color comics or composing in color for comics has been very difficult until the current digital era.
There's another technical problem if you want to compose on paper in color. The problem is how to work up the image in color and draw over the applied color. If I use watercolor for example to paint a blue sky and then draw a plane in the blue sky - my pen lines may possibly bleed depending on the materials I use. Or if I want to color a blue sky in colored pencil, draw a plane over top of it and then need to erase my plane - I'll probably mess up the nicely applied color that was the blue sky.
If I use gouache or acrylic paint, I may build up the surface of the color too much that now a pen won't go over the ridges and puddles of paint. So, I switch to a brush and am now sort of painting my lines. My lines are thicker and it all gets brushy in a way that I don't want. I want clean, consistent pen lines in some places and the applied color is just making it impossible. What to do?
Well, one solution is the blue-line technique. See here for a thorough look at the process. Basically, you draw your page in black and white, print it on acetate and then also print the page on to Bristol board in non-photo blue ink. So you can paint color within the lines on the board and the black lines on the acetate are a separate layer. It's sort of like painting an animation cel - but you can get more textures on the board - the cel flattens the paint on one side, like painted signs on glass at the grocery store.
So, the technical problems of composing in color have obviously played a big role in how all cartoonists create work in color. That's all I'm saying. Some folks make comics with gray tones but usually the tones are added after the image is complete. What I want to look at is composing with a sketchy gray underdrawing and finding "containment" lines after finding the shape of the thing being drawn. I think working up images from light to dark helps me "see" the image more clearly than defining containment lines first and then adding tone. I also think this process relates directly to understanding and applying color.
Certain markers work well in this instance. Like I said - the Prismacolor markers are good. My pen lines do not bleed when I draw over the applied marker. And the different percentages blend nicely, I think.
Working in gray is helpful to me because it offers a middle ground. Meaning I can draw a landscape background in gray and then, with a black pen, draw a person walking in the foreground - and that person will come forward in the picture plane and the background will recede. I can use one color, black, and get a very wide range of tones that will allow me to layer the picture plane for visual depth. And to me, it's a different process than drawing all black lines first and then adding gray tones. I'm finding the silhouettes of the entire image and then finding, choosing the lines I want. If I drew all my lines first to compose, then it's a different drawing altogether. And again, that's a personal preference, I'm just trying to explain my process in hopes that it's helpful to others. Take a look at Figure 1 below.
You can also separate the process of finding lines from determining the silhouette like you do in printmaking. See Figure 2 below. I drew the chair silhouette in gray and then on my lightbox I picked out lines in black on a separate piece of paper (with the first tone drawing under my new sheet for the black lines). So then I have two different "plates" for the printing process. I can combine the two plates as one drawing. I'm also trying to show here how you can determine the silhouette and then find the lines as a two step drawing process on the same piece of paper OR separate the tone drawing from the line drawing and combine them in the printing process.
The process of contour line drawing - where every shape has a containment line - is a very different mental process than seeing silhouettes. I like doing both, of course, but the gray underdrawing works well for me when doing comic book layouts. When I walk around my neighborhood sketching landscapes I prefer just drawing in "straight pen" without any underdrawing. So, these are two different processes that I like to use to help me "see" differently. Seeing in tone and color is very different than seeing in lines. The computer you are using right now doesn't have a black line around it - it exists in space as tone and color and shadows and light. So depicting those shapes in color by containing the shapes first with black lines and then coloring all the contained shapes is a little backwards, no? But somehow that is practically a law in comics - the drawing process is separate from the coloring process.
Homework assignment: try drawing cars. Cars are tough to draw with just lines. Everything looks off usually when I try and draw a car with just lines. So try drawing a car (from life - not out of your head) with a gray underdrawing and then add lines over the gray shapes. See Figure 4 below. I think it helps me see the light and shadows and all the subtle forms of the car's body before I pick out the lines. Try it! Get out of the house!