@alyssa i can't think of an example of a colour i consider "default" and i'm also not sure how a colour can fail to count as a colour, so in short i have no idea how to parse the question,,, but my answer is probably still purple anyway
@pan v fair. it's an awkward question to phrase because the English word most directly similar to the inspiring Spanish word sadly has dreadful associations. the not-counting-as-a-color part because it some might consider "white" or "black" a color and others might not (or, one is but the other isn't)
i was prompted to ask this by the Spanish word "colorado/a", which is analogous to "coloured" (minus the associations that has in English...), but generally specifically means "red" rather than just having some unspecified colour(s)
@pan could be. i tried looking and couldn't find any other Romance languages that clearly had the same thing going on except probably Portuguese and Galician. so i wonder if there's something to do with a pre-Roman substrate in the Iberian peninsula (or I guess could be Gothic or Arabic influence, but I couldn't find any sign of a similar phenomenon in either in my cursory look either)