How many colors are there in the visible spectrum?

The question mixes two different aspects of color vision:

  • “Spectrum” is a physical term based on the fact that light consists of photons of different frequencies.

We can only see the range between 380 nm and 780 nm.

  • “Color” only arises in the brain when the signals of the different receptors in the eye are evaluated.
  • The area of spectral colors can be seen in nature in a rainbow.

    From 380 nm begins purple blue, which is the transition from ultraviolet to the visible area. On the other hand, at 780 nm deep red, to which the infrared, which is no longer visible but can be felt as heat, connects. In the picture you can see two rainbows, each with the colors in different order. Why, is explained in rainbow.

    In our eyes we have three different cone types, each of which is sensitive to different frequency ranges (color valences):

    The proteins that receive the light and are

    chemical signals are predominantly encoded on the x chromosome. Therefore, a color lack affects mostly men, because they have only an x chromosome. If there is a mutation there, it cannot be balanced by an error-free gene on the other x chromosome.

    In women there is another interesting deviation, in them one finds tetrachromates.

    The genes for L- and M-opsin are on the X chromosome in humans.

    Since women have two X chromosomes, they can … an additional modified color receptor occur, the maximum sensitivity of which is usually between those of the red and green receptors and which is therefore to be qualified as a yellow or orange receptor. This four-color pigment genotype occurs in twelve percent of all women. … However, individual cases of experimentally verified tetrachromatic, i.e. more differentiated, color perception have already been described.

    These women then recognize color differences in yellow to orange that are not visible to other people.This is the so-called “gold sensor”, as a professor of lighting technology I am familiar with has always said in his lectures.


    Because we have three different color receptors, many properties of color vision can be modeled and examined using the mathematical model of a three-dimensional color space (color space).Depending on the field of application, there are completely different ones, the values of which can be converted more or less well into each other. For everyday use, a division in hue, saturation and brightness is suitable:

    Another representation in the xy color space is known:

    The colors of the rainbow can be found here in the upper arc from blue to green to red (spectral curve).

    The numbers at the edge (380, 460, …, 520, …, 700) represent the wavelengths of the spectral colors in nanometers. The lower straight line below is called “Purple Straight”, it is not found in the rainbow, just like all colors inside the chart. They are created by a combination of radiation from different photons only in the brain. Point D65 is the so-called white dot. D65 because of the sun’s color temperature of about 6500 Kelvin.This is the color that a grey-covered sky has dueto the light of the sun (standard light).

    The hue here decreases from the outside to the inside. The third dimension, the brightness (technical term luminance), is not shown here at all.

    The triangle shown in the diagram is interesting.When an image is displayed on the screen or an image is printed in a book, a colored dot is composed of even smaller dots with a cleaner color. On the screen today usually through the light a blue, green and red LED. Printing often uses the colors cyan, magenta, and yellow, and carbon (CMYK). The addition of the three or four color subpixels then produces the desired hue. The triangle shows us that it is not possible to create all the colors on a screen or book that our eye can see through an additive mixture. The colors outside in nature always seem a bit more vivid than on a screen or in a book.

    How many colors can we see now?Here is an answer: Five times wise – How many colors does man see?:

    • 200 shades.

    These correspond to a circular orbit in the above xy diagram.

  • 200 to 500 brightness levels.
  • These correspond to the missing third dimension in the diagram above.

  • An unspecified number of color saturations (these correspond to an ever-fading color as we move from the edge of the chart toward the white point.
  • According to the article, it should therefore be about 20 million.That would be the simple answer to the initial question, but it is not that simple. Any answer between 200 and 20 million is correct.

    In fact, macadamel lips are used in perceptual physiology.These are represented in a color chart like this:

    For examination, you always show two colors on a screen.

    One color represents the center of one of the ellipses, and the second color is varied. Then the subject is asked to find a color difference. A recognizable color difference marks a point on the edge of the ellipse. What you can see from the diagram is that the ellipses are different for different colors, so the properties of our color vision are not displayed linearly in the diagram.


    So far, we have only dealt with the physical and physiological aspects of color vision, but the question of the number of distinguishable colors extends even further into the psychological and cultural sphere.One can point this aspect with the question: Does the number of distinguishable colors depend on the number of color words in the mother tongue of the visioner?

    By and large, i don’t think so, as experiments have shown.In border areas, however, probably already. Russian, for example, knows two words for blue: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . And Russian native speakers can actually distinguish shades more accurately and quickly than we do in the blue area.

    I am not surprised by this.Color perception takes place in the head and in the brain there is no sharp separation between areas responsible for vision and language. If there are more color words in one language than in another, you as a native speaker are forced to take a closer look in order to communicate correctly. Children learn with their mother tongue not only words, but also seeing (and smelling, tasting, etc.).

    And I read another interesting thing a long time ago: in antiquity (Rome, Greece) there were much fewer color words than today (in Homer the sky was “black”).Their numbers later increased when they learned to color objects. Before, it made no sense to give color attributes to objects if they do not differ in color. “Green Meadow” and “Blue Sky” are Pleonasms.But when you dye clothing, names like “green dress,” “blue pants” have a benefit, and the corresponding color words meet communicative needs.

    So: the richer our culture is, the more color words our language contains, the more colors there are.

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