Each society has its own customs about colors. Japanese is now based on a seven color （七色） scheme, but Japanese has not always been this way. This will become quite apparent as we look at individual colors.
A lot can be said about the nuances of each color, how to be more specific about shades and hues, and what sort of idiomatic expressions can be made with color. By now you should have already learned the basic colors through example sentences thus far. So, this lesson is more about knowing exact details about colors, and it will be expanded over time.
There is a noun and an adjectival form to each color. Also, there are additional Sino-Japanese variants for many colors, which can be made adjectival by adding の.
1. All colors of native or foreign origin may be followed by 色. Certain colors should be used with 色. For example, 灰 just means "ashes". Gold and silver must have 色 in order to not be confused with the actual elements. Words such as ターコイズ and オレンジ can be understood to mean the color, but they really refer to the objects. Without 色, 緑 may mean "greenery". 紫 as a noun may refer to soy sauce in sushi restaurants.
2. The native versions of gold and silver are rare. In fact, the one for gold is never used but in 白銀色, 銅色, and the like.
3. Most of the Sino-Japanese readings are rare.
4. 青, not 緑, is the color used for streetlights for "green". 青 may also mean "greens" in expressions like 青物市場 meaning "vegetable market". It is also the color for pale face, youth, and freshness in plants, coolness, the sea, and even the color of moonlight and evening mist. It may also refer to black as in a horse's coat.
5. 茶色 is "brown" instead of "green" because when tea was first introduced to Japan, it would be shipped to elites in hardened, steamed form. From then, it would be cut up and boiled in hot water and drank. As "green tea" variants would come later, the color of the original tea drinks became the Japanese word for brown.
Light and Dark Colors
Light colors are expressed by using 薄い or 薄～. For dark colors, use 濃い. Now, there will be colors that are light or dark variants of a general color. 淡い is "light/faint" and its antonym is also 濃い.
There are light yellow flowers, aren't there?
This flower's color is pale/weak/thin.
Mr. Takahashi's car is that dark green one, right?
The light crimson of a plum
The fragrant olive (went) from dark green to a light green and the Tartarian Aster (went) from light yellow to greenish brown.
From 野生の風 by 村山由佳.
Sentence Notes: 裏葉色 literally means the color of the back of a leaf. 鶯（色） is the color of the wings of an 鶯 (Japanese bush warbler). You do not have to remember the 漢字 for 犀, 苑, or 鶯 for the time being, but literature often exploits even more specific colors, and spellings can get trickier.
Colors may be put together to make things such as "white-black" and "yellow-green". The resultant expressions may be read with either 訓読み or 音読み. 音読み are rarer and reserved for the spoken language with exception to #10.
Black and white
Really light green
赤字 and 黒字 are deficit and surplus respectfully. They are words that typically confuse students, although there are similar expressions in English. For example, you can say "to be in the red". When you get a failing grade, you can say you got an 赤点. However, 黒点 refers to sunspots. So, it is not the opposite of 赤点. Instead, the antonym for 赤点 is either 及第点 or 合格点.
It is also important to note that the phrases 肌が｛白い・黒い｝ are NOT used for nationality/race. Rather, they refer to someone's complexion.