黄 alone already means 'yellow', so why do I always see 黄色 used to mean 'yellow'? 赤、青、緑、等等等 can, and are, often used alone. However, I never seem to see 黄 used by itself... Is there any major reason why this is? Is this actually even the case?
P.S.
What is the particular nuance of attaching 「~色」 as suffix to colors? Ex: Is 青色 vs 青 akin to saying "the color blue" vs just "blue"?
My understanding (which could be wrong) is as follows:
黄 "yellow" vs 黄色 "the color yellow", it's basically the same.
Adding the 色 just restricts what you're talking about to the color (rather than some other possible meaning for the kanji preceding it)
I think that people just use the one that sounds more natural. With 黄 it may be more useful to say 黄色, because there are so many homophones to just 黄. Also, if you are talking about multiple colors, it seems that the tendency is to be consistent with keeping or dropping the 色 for all the colors talked about (but it's not a hard rule by any means).
However, if you add -い to 黄色, it's an adjective. 黄 alone still means yellow, but added to other kanji, most likely describes a yellow ___, or could be something else for its own etymological reasons.
