Roch:Oh my! For that one, someone would be better to talk about "kompletigaj koloroj" or something!

https://en.wikipedia.org/wiki/Complementary_colors

I agree that it is difficult to determine "the opposite side of the spectrum" of white, as white is all over the spectrum...



Alia pensero: Se turo estas alta, do foso estas malalta?

in Esperanto, i found that every simplification is only apparent, because the difficulty disappears from one level and reappear in another one. think about MAL (saving thousands of roots and, in the other hand, douting about neresponsa and malresponsa, nereala and malreala, nelogika and mallogika, neprobabla and malprobabla), and when you ask for advice, they say "forget logics, embrace habitude".
when you use a language in a illogical way, simply by imitation and intuition. you are not worry about logics, you didn't learn it by logcis or rules.
of course, esperanto is a language of habitudes more than a language of logics. but when you read that there is an exceptionless language, you imagine that is regular and logical, so you could use a higher level of logics to learn and use it. that is an error, and in that way you will found esperanto more difficult, if you are not so keen in logics. and if you are keen in logics you will found very difficult that the normal esperanto speakers understand you.

you put on the table an important challenge for every language, not only esperanto:
if not completely but more and more:
how to put every concept as a root or underivated?
in the case of adjectives as long, short, white, black there is a relative simple way:
long, gnol, kcalb, black,
like that you can perceive kcalb as a root, and black as a root,
and you can save thousands of short adjectives from english.
that is not a conceptual empoverish: kcalb is a root.