How Many Colors Exist?

Our perception: As far as I know, colors are just altered frequencies of light. According to Wikipedia, we can see wavelengths from about 380 nm und 740 nm. This agency we can see ablaze with abundance from about 4.051⋅1014 Hz to about 7.889⋅1014 Hz. Is this correct? I don't apperceive if time (and frequencies) is detached or connected values. If both are continuous, an endless bulk of "colors" would exist. If it is discrete, there ability still abides no top bound.

A top bound? I begin the commodity Orders of consequence of frequencies. The Planck angular abundance seems to be by far college than all added frequencies. Is this the accomplished abundance which is possible? Do college frequencies accomplish faculty in physics?

Why do I ask this question: I am apperception the agent amplitude R4 like the R3, but with colors. I charge a complete bulk of colors if this should accomplish sense. In actuality the bulk has to be uncountable.

First, the blush is bent by the spectrum of the electromagnetic radiation in the arresting range. A lot of colors cannot be produced by an individual frequency. On the added hand, not every spectrum gives an altered color, because we alone accept three altered receptors in our eyes (actually there are four, but one blazon is not acclimated for free color). Accordingly the complete blush accession is based on three-dimensional amplitude (this is why about all blush spaces, like RGB, HSV, HSB, and YUV accept three parameters). Agenda about that admitting of this, it is not accurate that all colors can be generated by bond just three colors (you can call all colors in e.g. sRGB, but again you charge abrogating ethics for some colors). This is because not all activation patterns of the receptors can be produced by light. Indeed, all ashen colors (that all colors which accord to ablaze of just one anchored frequency) cannot be alloyed from annihilation else. As well agenda that this three-dimensional amplitude as well contains the accuracy (the HSV, HSB and YUV blush spaces abstracted that out as a specific coordinate), accordingly if you agency that out, the accurate blush amplitude has alone two ambit left.

However, we cannot analyze approximate abutting colors, accordingly the accurate blush spectrum is in fact finite. About there's no way to carefully ascertain the bulk of colors; absolutely the adaptation of spectra into colors is not as able-bodied authentic as the aloft would accomplish you think. For example, our acumen makes a white antithesis (that's why in analog photography the colors attending amiss if you fabricated e.g. a photo in electric ablaze with aurora film, and why agenda cameras appear with automated white balance), as well of searching for a best time at the aforementioned blush at acceptable brightness, the receptors get "tired" (that's why if you again attending at a white wall, you'll see the angel in commutual colors). As well assertive patterns of acuteness change are perceived as colors. In added words, whatever you do will alone be an approximation to accurate blush perception.
An animal eye may alone analyze bags or millions of colors – obviously, one can't accord a complete bulk because colors that are too abutting may be afield identified, or the aforementioned colors may be afield said to be different, and so on. The RGB colors of the all-encompassing avant-garde PC monitors accounting by 24 bits, like #003322, analyze 224∼17,000,000 colors.

If we carelessness the imperfections of the animal eyes, there are of advance continuously abounding colors. Anniversary abundance f in the arresting spectrum gives an altered color. However, this counting absolutely underestimates the complete bulk of colors: colors accustomed by an altered abundance are just "monochromatic" colors or colors of "monochromatic" light.

We may as well amalgamate altered frequencies – which are something absolutely altered than abacus the frequencies or demography the boilerplate of frequencies. In this added acceptable counting, there are ∞∞ colors of ablaze area both the backer and the abject are "continuous" infinities.

If we overlook about the afterimage by the animal eye, frequencies may be any complete absolute numbers. Well, if you're strict, there is an "academic" lower complete on the frequency, associated with an electromagnetic beachcomber that is as continued as the arresting Universe. Lower frequencies absolutely "don't accomplish sense". But this is just a bookish affair because no one will anytime ascertain or allocution about these acutely low frequencies, anyway.

On the added hand, there is no top complete on the frequency. This is affirmed by the assumption of relativity: a photon may consistently be additional by addition canal if we about-face to addition advertence frame. The Planck abundance is a appropriate bulk that may be complete out of accepted constants and assorted "characteristic processes" in breakthrough force (in the blow anatomy of a actual article such as the minimum-size atramentous hole) may depend on this appropriate frequency. But the abundance of an individual photon isn't in the blow anatomy and it may be arbitrarily high.

The colors which are perceived by humans are authentic by the bulk to which the ablaze will accelerate the red, green, and dejected photoreceptors in the cone beef of the eye. There are alone three detached colors we can perceive, and they are red, green, and blue. The statistics of the about and complete excitations, the bulk of red, green, and dejected averaged over abounding beef and over abounding time steps, defines the perceptual blush space. It is somewhat vague, because the best you average, and the added beef you accept to boilerplate over, the bigger you can analyze the colors. But the gradiations become absurd afterwards an assertive bulk of refinement.

The wavelengths of ablaze are not in any way primary, the acknowledgment of the three photoreceptors is. The acumen altered wavelengths accept altered colors are because they accelerate the altered receptors differently.

This agency that there is a three dimensional subspace of colors, which is authentic by the bulk to which the academician can accommodate the arresting for red, green, and blue, and actuate the acuteness of anniversary component. The alone way to be abiding of the bulk of gradations of anniversary is to do cerebral testing: attending at an analysis of the acuteness calibration for an authentic blush (a blush which excites alone one of the photoreceptors) and see how abutting the acuteness can be afore adjoining intensities cannot be anxiously distinguished. It is apparently amid 255 and 512 accomplish for red and blooming in the accepted ambit of a monitor, and amid 100 and 256 for dejected (this is a assumption based on my own memories of my own perception). This is in the accepted "octave" of a computer awning (the awning is not abutting to blinding, nor is it anytime almost visible, but the eye is logarithmic, so this ambit should be the aforementioned in the absolute bulk of octaves, at a lot of 10, I'll say about 4, and added for red/green again for blue, so that the appropriate appraisal is about 1000^3, or a billion colors.

But this does not yield rhodopsin acknowledgment into account. The rhodopsin acknowledgment is abstracted from the blush response, because the rhodopsin ambit is overlapping with all three receptors. If you cover rhodopsin as separate, you would accept to accumulate by addition 1000 attainable values, or an abundance colors. Some of these colors would alone be attainable by bogus means--- you would accept to activate rhodopsin after aesthetic the red, green, or dejected phosphors, and this ability be attainable chemically, like if you accept taken a consciousness-expanding drugs, dream states, oxygen deprivation. Addition way ability is to use afterimages, which will abolish the acuteness of assertive receptors.

If you are because animal eyes there is an audible (and decidedly small) bulk of apparent colors. This is accepted as a MacAdam diagram and shows an arena about an individual color, on a blush diagram, that is duplicate from the blush at the center. The absolute bulk of colors would be the bulk of ellipses bare to absolutely ample the blush space. Acutely this depends on the individual's age, gender, lighting, etc

While a specific abundance of ablaze has a color, it does not abnormally ascertain that color. Animal eyes accept 3 altered "color" receptors, anniversary of which is added acute to some frequencies than others. There are complete bulks of colors, but there is apparently some complete as to how cautiously a being can analyze amid altered intensities advancing from anniversary blazon of photoreceptor.