Okay, let me see if I can make it make sense.
The first step of colouring is called "Flatting." Flatting is when you break down all the basic shapes before you colour. The flatting step is usually done in random colours*, with colour choice done later. This is mainly because usually the flatting step is done by a colourists assistant called a Flatter. The flatting on the Li'l Depressed Boy is usually done by Thiago Ribeiro, but I was excited about this page so I flatted this one myself.
The exact way I do my flats is weird. To the best of my knowledge, no one else flats this way with the exception of Chris Fenoglio, who I trained. But the basics are all the same -- you start by breaking down large shapes, and go in and break down the individual elemtns in those large shapes until everything is broken down.
I personally start with seperating the foreground from the background. I then copy that big blob of yellow you see onto a seperate layer. This will help me down the line when I'm doing shadowing phase, because it'll allow me to make a selection that is just the characters that I can use as a mask. This mask makes it so that I can draw the shadows on and draw past the lines of the characters, without it getting on the background.
So after that, I take the big yellow blob and I break down the individual characters into seperate individual elements of each character. LDB and Jazz, I use the actual colours, but the rest I stick with the random colours trick, as it's faster. Then I break down the background in the same way. This is all done on the same layer -- that second layer I created only exists to make that mask selection. You wanna avoid doing too many layers, as they make the file bigger and that takes extra time to load and save.
After I'm finished flatting with the random colours, I go through and do some colour selection on the characters. All these other girls were created during the Blue-Tone era of the book, so they don't have pre-made colour choices. I try to think of what I was thinking when I created them years ago, and colour accoringly. I choose these colours from multiple ways: Off of the colours palette; By mixing two colours; Or by tweaking it with the Hue/Saturation mixer in Photoshop.
Once colour choice is done, I create a new layer. I fill this layer with white, then set the layer options to Multiply. Grabbing the foreground mask, I then draw in all the shadows on the characters using the pencil tool and the bucket tool set to "use all layers." I one use shade of brown for everything on the foreground. Then I do the same with the background, using a different shade of brown and a light tan.
Then two more layers are created and textures are pasted in. These layers are also set to multiply, but at a lower percent opacity. I move the textures around every time, so that each page's texture is unique.
After that is done, I delete the mask layer and end up with only four layers in the whole file. (With the line-art on a seperate channel, instead of a layer) I save for the last time. (Save early and save often)
Then I finalize the page and do something that is called "Trapping." This takes the file and conglomerates all the layers and the extra channels, and makes it so that if there is a printers off-set on the black channel, the readers won't notice. This is done by putting some of the colours underneath the black, as well as other stuff that I'm terrible at explaining. (For an example of a badly trapped page, take a look at the 1998 Sunday strip in the back of Volume Zero -- see how there is white around the black lines where there shouldn't be? That's because I forgot to correct my untrapped pages from back then)
Okay, hopefully that makes it make a little more sense.
* Not all colourists like their flatters to do random colours. When I was flatting on Chew, Rob Guillory gave me a style sheet with the basic tones he wanted for the main characters and wanted each character flatted that exact colour so that he wouldn't have to spend time correcting my random choices on every page. You can see me refer to my own style sheet for choosing the colours to LDB and Jazz.