The most common descriptions used to build a memorable NPC focus on their visual appearance, unusual quirks and mannerisms, or perhaps a voice or accent. In a few rare cases other senses, such as smell (seriously, I’ve used this) or…taste. One area that’s seldom used is the color pallet to describe an NPC. On the surface this sounds strange I’ll grant you, but it works!
I stumbled across this several years ago while reading Kushiel’s Dart  by Jacqueline Carey . At some point during the enthralling book I noticed that in my mind’s eye that I was associating many of the characters with specific colors. On a second read through I noticed that several characters had repeating colors used in their descriptions, most often in describing their wardrobe, a crest, or sigil of some kind. The colors were subtly used but subconsciously, as the actors played their roles in my head, I was seeing them, perhaps for the first time, in full color.
A few years later I did a rather expansive Fading Suns  campaign with a broad dramatis personae. During each write-up I also included color keywords so that when the players interacted with the NPCs I would use those same terms/colors repeatedly. (Coincidently this is also where I used a little bit of smell with some major NPCs, the smell of roses lingering in the air as they pass by, for example.)
I’ve only a small sample size to work with, but I’m told by the players that it did work. The NPCs were more memorable and that, subconsciously, when asked about it much later, the players described the NPCs back to me, also in full color.
When you use an awesome tool such as “Masks ,” we have, of course, tried to appeal to as many GMs as possible to maximize utility. Space constraints also dictate how much detail we could use and still make the entries quick and juicy. Consider writing in the margin and assigning colors to your NPCs and then reference them subtly during play. Also, expand your own color pallet with shades and variations. Don’t go with “brown” or “red,” use more evocative colors such as “cherry red” or “the hue of a deep, red rose.” Reference a Crayola crayon box for shade ideas, car paint colors, or other online resources.
The key is to remember to include these colors either on or around your NPC to reinforce the association. Because this is something new, it takes some practice; you’ll find yourself having to be deliberate in your descriptions, rather than ad hoc.
What interesting or unusual ways do you describe your NPCs to make them stand out in your player’s minds? Share below!