This one taxed my ingenuity, and the result makes me look like a much better gradient painter than I really am. I can do a decent gradient at about the size of the Platypus, which is maybe half this big, (the small size allows me to work the ink while still wet, so I could slather red into the tail before the Indian Yellow was quite dry, and then smooth out the color with colored pencils) or I can go into pure megascribble mode, which has its own advantages, but gives a definite texture.
For the flat, pale yellow I kept seeing in my head for the otter, though, none of my usual methods were working. I shot myself in the foot on the first take by doing it much too large, and then I screwed up big time with the ink color on the second one. So for the third, I sat down and went "Why am I killing myself here when I'm printing the sketch out ANYWAY?" and printed the base yellow-to-orange out onto the paper as well as the extremely pale guidelines for the sketch. That saved me an infinite amount of grief on the coloration and let me just work the gradient with layers of Prismacolor and introduce pinks and peach and darker reds into the colors.
(It occurs to me that I'm making this sound rather more painless than it was, since if you're using an inkjet printer as another painting tool, I swear it NEVER comes out right on the first try. Over the years, I've probably put a good thousand hours--and probably three or four thousand dollars!--into learning to make this one brand of printer do what I want them to, and even so, there's four or five prints of the otter sketch with bits cut off or placed wrongly on the page or the wrong color littering the studio this morning. Still, if you're comfortable with your printer--and using waterproof ink!--this is definitely a method worth trying.*)
*As a caveat, I would not recommend heavy-duty experimentation with any printer that you do not own. The ink I have wasted is measured in gallons by now, we could wallpaper a cathedral with misprints, and I know I killed at least one cheap Epson back in the day trying to make it do stuff it was not happy doing.