Color words in Japanese exist in two different forms: i-adjectives and nouns. Some of them are present in only one form (usually the noun form), but many are present in both. I’ll present a list of basic colors along with the different forms that color exists as, with the i-adjective form first (if present).
- Red: 赤い（あかい） ／ 赤（あか）
- Green: N/A ／ 緑（みどり)
- Blue: 青い（あおい） ／ 青（あお）
- Yellow: 黄色い（きいろい）／ 黄色（きいろ）
- Grey: N/A ／ 灰色（はいいろ）
- Orange: N/A ／ オレンジ
- White: 白い（しろい) ／ 白（しろ）
- Black: 黒い（くろい） ／ 黒（くろ）
- Pink: N/A ／ ピンク
- Brown: N/A ／ 茶色（ちゃいろ）
If you get into different shades（ex: 瑠璃色) and older terms (ex: 橙色) there are hundreds of color words, but the above is a good start for expressing everyday colors. I’ve also omitted a whole set of noun forms that end with 〜色 such as 緑色（みどりいろ） and 青色（あおいろ), which are a bit less common in my experience.
The reason one needs to distinguish these different forms is that their usage and meaning is different. For example, the i-adjective forms are simply placed in front of a word to modify it, whereas the noun forms typically require a の in-between themselves and the word to modify.
- 赤い電車 [red train]
- 赤の電車 [red train]
If you search around the net you’ll find occasionally people will use な instead of の after noun colors. For example “赤な電車”. From what I understand this is not grammatically correct, but it’s not a major mistake either and people will still understand you even if you mistakenly use な。
The negative forms are be conjugated as shown below.
- 白くない雲 [the cloud that is not white]
- 白じゃない雲 [the cloud that is not white]
There is another key difference between these forms. I-adjectives inherently contain the concept of “is”, which is why it is awkward to say ”赤いだよ”, and more natural to say ”赤いよ”. Another way to say this is that ”赤い” literally means “it is red” whereas ”赤” just means “red”.
This is important because if someone asks you “好きな色は何ですか？” (Which color(s) do you like?), you should answer with the noun forms. For example:
- Q: 好きな色は何ですか？
- A: 赤です Correct
- A: 赤いです Unnatural
There is one case where both forms follow the same rule, which is when expressing there is something of a certain color, like “the black one”. In both cases you simply add a の to end end of the word, and the result is a noun.
- 黒いの [the black one]
- 黒の [the black one]
So when using color words to describe something, which form is best? Personally I just the i-adjective form if present if there is one, and if not I use the noun form. But feel free to use either except in cases where a noun is required (these are pretty rare).
(Featured image taken from Wikimedia commons here: http://en.wikipedia.org/wiki/File:Colouring_pencils.jpg)