Is it true that there is an infinite number of colors but this doesn't mean that the human eye can distinguish an infinite number of colors?

 

Just as there are infinitely many numbers between 380 and 740 - including all of the fractions, of course - so there are infinitely many wavelengths between 380 and 740 nanometers - the visible spectrum of light. That doesn't even count the different tints and shades obtained by mixing in white, black, etc. So, it can be argued that there is an infinite number of colors, if you look at it that way.

http://www.pburch.net/dyeing/dyeblog/C128544578/E1447734446/

Yes, there are.

Color is a subjective experience created by specific wavelengths of light reacting with specialized cells in the eye. The number of colors you can see is based entirely on the number of different types of "color" cells in your eye. Humans (mostly) have three which roughly, but not exactly, correspond with RGB. This is why they're considered the primary colors of light. Animals with different numbers of cones (the color detecting cells) may see more, fewer, no or different colors. People with color blindness have one or more of these three types of cone that do not function properly, which is why they have difficulty distinguishing between certain colors, because those colors do not exist for them.

 

Colors themselves do not "really" exist in nature. They exist purely subjectively as a way to distinguish between different wavelengths of light. Defining the number of colors then really becomes a matter of determining the number of hues that the human eye can distinguish between, which is a somewhat controversial subject, but the number is significantly smaller than infinity.

Color is a subjective experience created by specific wavelengths of light reacting with specialized cells in the eye. The number of colors you can see is based entirely on the number of different types of "color" cells in your eye. Humans (mostly) have three which roughly, but not exactly, correspond with RGB. This is why they're considered the primary colors of light. Animals with different numbers of cones (the color detecting cells) may see more, fewer, no or different colors. People with color blindness have one or more of these three types of cone that do not function properly, which is why they have difficulty distinguishing between certain colors, because those colors do not exist for them.

 

Colors themselves do not "really" exist in nature. They exist purely subjectively as a way to distinguish between different wavelengths of light. Defining the number of colors then really becomes a matter of determining the number of hues that the human eye can distinguish between, which is a somewhat controversial subject, but the number is significantly smaller than infinity.

But the spectrum is continous - there is no inherent lumpiness. The fact that colour is a roundabout name for wavelength invented by humans does not detract from this non-lumpy nature. And detection by unaided human senses has long since stopped being the gauge by which (even very human concepts) are measured.

imatfaal is correct; this was posed as a physics question, and since the spectrum is continuous one has to say there are an infinite number of wavelengths. The issue of color perception of the eye is a question of physiology, and that's a separate discussion.

True, but wavelengths and colors aren't necessarily the same thing. Every wavelength doesn't have a distinct color that is distinguishable from that of every other wavelength.

 

If the question is "is there an infinite number of wavelengths in the visible spectrum" then it is a physics question and the answer is yes.

 

If the question is "is there an infinite number of colors in the visible spectrum" then it's a physiology question and the answer is no.

 

I do realize that the question is posed as a physics question, but it seems to be framing a philosophical question that actually has an answer that is more accurately provided by the physiological question than the physics one.

 

Unless you're just defining color as being the wavelength rather than the subjective visual experience of the wavelength, but that seems less accurate relative to what most people are talking about when they say color.

you can't get a light source that will emit one exact frequency. theoretically yes but practically no. the atom that emits the light is moving so there will be doppler shift. the apparatus measuring the emitted light will move giving more doppler shift. this is due to the kinetic energy in the system causing random motion. also to measure an exact frequency you'd need and infinite number of wave cycles to measure.