Red is a basic color. The work of Kay and Berlin on the evolution of color names in languages shows that, after white and black, red is the most basic of color terms. Red plays a key part in Hering's color opponent theory, and is one of the elementary colors in both the Munsell Color system and in the Natural Colour System (NCS). The CIELAB color system has an axis which is sometimes referred to as the red‐green axis. But unique red is about 25° degrees counterclockwise from the positive a* axis. This article answers the question of why this is.

中文翻译：

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为什么CIELAB a *轴指向洋红色而不是红色？

红色是基本颜色。凯和柏林在语言中颜色​​名称演变方面的工作表明，除了白色和黑色之外，红色是最基本的颜色术语。红色在Hering的色彩对抗理论中扮演着关键角色，并且是Munsell色彩系统和自然色彩系统（NCS）中的基本颜色之一。CIELAB色彩系统的轴有时称为红绿色轴。但是唯一的红色与a *正轴逆时针约25度。本文回答了为什么这样的问题。