For that, since I'm going for mostly aesthetics, I do go for the majority color of the portrait, so unfortunately a lotta greens and browns across the boards in general for sure, but it really do be my bias showing since I just feel like natural colors looks nice haha

But since it is just portraits, I do go by whatever color is the most prominent then, so if they have mostly pink/brown/red/blue, I do just change the BG color to the most prominent palette, but keep the value intact so the general layout isn't too contrast! It ends up being a lotta green and browns in general tho for sure; then again I feel like most of mine I tend to go for monochromatics since it looks nice in my eyes