how is indigo a color in the rainbow?

Question

Growing up, I was taught that rainbows have 6 colors. Red, orange, yellow, green, blue, and purple. It makes sense as it goes from primary color (red) to secondary color (orange) back to primary (yellow) back to secondary (green), to primary (blue) and finally ending on secondary (purple). Indigo is a blend of blue and purple, but purple is a blend of red and blue…..

In: Physics

Answer 1

Purple is not in the rainbow, it is a mix of red and blue. Since red and blue are on opposing ends of the rainbow, they cant mix.

Hence Indigo, a kinda bluish purple without any actual red in it.

But our eyes are kinda imprecise, so seeing indigo wavelengths also triggers our red cones, so it appears purpleish to a human eye.