There are 6 colors in the typical computer HSV rainbow. https://visual.ly/blog/wp-content/uploads/2012/04/RainbowEdges.png https://visual.ly/blog/wp-content/upl

There are 6 colors in the typical computer HSV rainbow. https://visual.ly/blog/wp-content/uploads/2012/04/RainbowEdges.png https://visual.ly/blog/wp-content/uploads/2012/04/RainbowEdg... At least that's what I see if you uniformly vary hue and display it in the usual sRGB display. (7 bands, red is repeated). That's why naive rainbow visualizations are such a bad idea and visualizations should use perceptual color scales instead. For Caveat: these perceptions are culturally relative. I'm born and raised in the US.