One of the fun things about coleus plants is that they can change how much color they have based on how much they are exposed to light (the ratios of colors change in new growth, it won't change what colors are there). I kept two clippings from my coleus propagation success and left one in a southern window (lots of sunlight) and one in a bright room but away from direct light. The results are pretty easy to see: more light meant more of the dark red coloring, and less light meant less red and more white/green. In general, coleus will produce darker colors if exposed to more light, and more lighter colors if they get less light.
On the left: Coleus grown in bright sunlight (southern window). On the right: Coleus grown with only indirect light.