English: This juice is purple.
日本語 1: このジュースは紫です。
日本語 2: このジュースは紫色です。
Does the kanji 色 need to be palced after colours?
From what I understand, sometimes the kanji 色 is necessary. For example, in 灰色, without the 色 kanji, it would just mean "ash", right? But, I don't get why 紫 needs to have 色 next to it.