What purpose does adding 色 to colors achieve?

Question

Like the title says, I don't understand the purpose of adding 色 to color words. For example:

• 緑のドレスを着ている vs 緑色のドレスを着ている
• 赤い車を運転した vs 赤色の車を運転した vs 赤の車を運転した

I know both styles are common, but in what situation would you use one over the other?

Answer 1

色 doesn’t play any particular purpose or add any particular nuance in the case of 緑. It just might sound a bit redundant to some people.

緑のドレスを着ている。

緑色のドレスを着ている。

色 is practically mandatory in certain other colors.

黄色のドレスを着ている。

茶色のドレスを着ている。

灰色のドレスを着ている。

黄土色のドレスを着ている。

It should not be surprising that words like 灰 and 黄土 need to be followed by 色 because they don’t refer to colors by themselves outside of very limited contexts.

Though 茶 is much more established as a standalone word for the color brown, and 黄 is nothing but the name of the color yellow, these still require 色 for some reason. It is such an integral part that it even appears in their adjective forms.

黄色いドレスを着ている。

茶色いドレスを着ている。

On a side note, it is interesting that the name of the most typical kind of Japanese tea (today) needs to be modified by another color, as 緑茶.

A few other basic colors have adjective forms (without 色), as well as noun forms.

白いドレスを着ている。

黒いドレスを着ている。

赤いドレスを着ている。

青いドレスを着ている。

If the purpose is to simply describe how the person looks, I would say these with adjectives sound slightly more natural than the following sentences with nouns.

白のドレスを着ている。

黒のドレスを着ている。

赤のドレスを着ている。

青のドレスを着ている。

Though the difference is subtle, these sound a bit like the speaker’s focus is on what color the person chose to wear out of multiple choices. In other words, the color seems to get more weight in 白のドレス than in 白いドレス, which is more about the dress and the color is only one of its attributes.

To me, 色 sounds more redundant with 白 and 黒 than 赤 and 青, and 緑 for that matter.

白色のドレスを着ている。[very redundant]

黒色のドレスを着ている。[very redundant]

赤色のドレスを着ている。

青色のドレスを着ている。

Answer 2

The meaning of 緑色 is strictly limited to the color green, whereas 緑 includes the color green and other figurative meanings like 'greenery', 'natural', 'environmentally-friendly', etc.

While the exact phrase 緑の can refer to something green colored (as would 緑色の), the difference is that this phrase could also have a figurative meaning. It can be used creatively to describe a variety of things associated with the concept 'green'. For example, take the phrase 緑の募金, which is used in this specific context to mean supporting local environmentally-friendly projects.

Answer 3

It is worth mentioning that this usage is probably inherited from Chinese, where each character corresponds, roughly, to a single-syllable word. Since there are only a limited number of syllables, many characters are pronounced the same, and it would be difficult to know which of several possible meanings you intended. The solution is to add some sort of 'qualifier': an extra word that clarifies the meaning.

Thus, '綠: green' becomes '綠色: green colour', '藍: blue' -> '藍色: blue colour', '紅: red' -> '紅色: red colour', ...

Answer 4

For a general answer, just look at what everybody else is saying on here.

I will note however, that the one exception is "Yellow" (黄色). Here, the "色" is baked into the name of the color itself!

For example you would say

赤いペン (red pen)

黄色いペン (yellow pen)

but

黄いペン

is non-grammatical.