Why is the rainbow only 7 colors if it's the different wavelengths that makes up colors?

"The colors of the rainbow are the "basic spectrum" from which all the light we see is composed. Although these colors merge smoothly, they are sometimes divided into red, orange, yellow, green, blue, indigo and violet (and other names). Just as various musical sounds contain the tones of the basic scale (often combinations of tones, e.g. chords), so any colored light is made up of its "spectral components. "

We only perceive seven colours but if you look closely at a prism, all visible colours are represented.

You broadly categorize light into those colors. If you want to, though, you can focus on the in-between hues, such as reddish orange, orangish yellow, yellowish green, greenish blue, and bluish violet... and give these hues new names (just make them up). After that you can consider them to be the MAIN COLORS, while red, orange, yellow, etc. are the in-between ones.

On the other hand, there's no reason to do that, since all you'd accomplish is putting yourself off the conventions that everyone else uses, without getting any redeeming social value out of your effort.

But however you define color, you, and everyone, can agree that there is such a thing as color. We can understand that the physical difference between one color and another color is a fairly trivial difference in the frequency of the light. But, no matter how slight the frequency difference, the psychological importance of color is very profound. Color exists even thought the colors transition into each other in the spectrum, rather than being each neatly compartmentalized. To say "it's all ONE KIND of light" is a crass oversimplification.

Also, color has a strong correlation with physical phenomena, such as the photoelectric effect, that has consequences independent of the human mind. A photon with an energy greater than the work function of an electron in an atom will unbind the electron and maybe send it clear of the material it was in. A photon with less than the required amount of energy will not do so.

You know, this discussion sort of makes me think about racial differences in humans.

There is an inifinite spectrum of colors that we see in the rainbow. We have only chosen to name them by the primary and secondary colors. For example red and orange. But there are thousands of shades of reddish orange in the rainbow.

Also the hue of a rainbow and brightness are constant, so you dont see various shades of the colors.

'Pink' is a very light shade of red. Brown is a combination of blue and red (IIRC?)

Also, the output of the Sun isn't a nice, 'flat power density over the entire visible spectrum' white light ☺

Doug

The prism is what split the white light. Those seven colors are the result from splitting the light. That is why you will not see brown, pink, or any other than those seven colors.

Because our eyes can only read a certain proportion of the 'visible spectrum' ( you may want to google that )

Brown, pink... are combination of colours. They are combinations of different wavelength...

There are more but we only see seven.

Mind sees what it chooses to see.

We believe what have been made to believe.

We hear what we choose to hear.

We speak what we choose to speak.

Same way.....

Choose different colours in your mind and believe me you'll see what you want to see.

Its proved. Not scientifically, but its my personal experience.