When do you use の to join nouns and colours/adjectives?

Question

When do you use の to join nouns and colours? I know that green pencil is 緑{みどり}の鉛筆 【えんぴつ】but I'm not sure if it's the same for other colours or adjectives.

Answer 1

When do you use の to join nouns and colours/adjectives?

Adjectives are made to modify a noun, so they don't need の: ex. 高い空.
Nouns basically need の to be connected to another noun: ex. 今日の天気.

For colours, it's something hard to tell if we don't know, but this page is affirming that we have only limited colours that can be used as adjectives.
Only four of い type: 赤い, 青い, 白い, 黒い, and two of ～色い type: 黄色い, 茶色い.
Ex: 白い雲, 茶色い写真, etc.

Other colors are nouns and always need （色）の to connect to another noun.
Ex: 緑の, 緑色の, ピンクの, ブルーの, 黄金色の, etc.