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How Do RGB Monitors Display That 4th Color?

Posted by Cliff on from the red-green-yellow-blue dept.

Pro-pain asks: "How can a standard RGB monitor display a fourth color?" It really doesn't. It's all an illusion and that pink you are seeing really doesn't exist.

8 comments

  1. Re:OMG LISTEN UP by djve · · Score: 1

    I agree. The original was slightly funny but its over now. Kill these jokes, please.

    djve

    --
    "There is magic in the web." - Othello Act 3 Scene 4.
  2. OMG LISTEN UP by crazney · · Score: 1

    ITS OVER APRIL 1st MIDDAY ---> STOP IT

    please.. slashdot admins, do us a favor and LOOK AT THE TIME/DATE..

    for gods sake.. are you all stoned or something? you've been posting crap for almost 48 hours now..

    geee.. i expect better of you.. afterall, thats what we watch the adds for!

    --
    stuff
  3. The eigth colour by Pogue+Mahone · · Score: 1

    I don't know what kind of crack the poster was smoking. My ROYGBIV monitor shows 7 colours without problems. Has trouble with octarine though.

    --
    Every bloody emperor has his hand up history's skirt [Peter Hammill/VdGG]
  4. Re:tetrachromat by QuietRiot · · Score: 2

    For the latter, color is nothing but the interpretation of a wavelength. Creating colors on your monitor is really just controlling the interference between the light waves.

    Color has nothing to do with the "interference" between the light waves. Your eyes can intercept two wavelengths and they appear to be of another. This is due to our eye interpreting the simultaneous stimulation of two wavelengths as another color. It has nothing to do with the two wavelengths "interfering" in the traditional sense.



  5. yuck. by jbridge21 · · Score: 2

    I have just one word for this story... LAME.
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  6. tetrachromat by wishus · · Score: 2

    You mean the "fourth color" that a tetrachromat would see? Or something other than red, blue, or green?

    For the former, I don't know.

    For the latter, color is nothing but the interpretation of a wavelength. Creating colors on your monitor is really just controlling the interference between the light waves.

    You know how you can mix pigments together to create different colors? Mixing the yellow paint with the blue paint makes green paint? That's all your monitor is doing with light waves, except that light has different "primary" colors. (Red, green, and blue, as opposed to red, yellow, and blue in pigments).

    I would really like to hope you were asking about the tetrachromats, though.

    wishus
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    1. Re:tetrachromat by Zeinfeld · · Score: 3
      except that light has different "primary" colors. (Red, green, and blue, as opposed to red, yellow, and blue in pigments).

      You men cyan magenta and yellow

      The incidence of four color vision is actually relatively high, a few percent of females but practically zero in males.

      When I worked in the chemical industry we had several females whose job was blending the various dyestuffs, most had four color vision, they could detect variations in shade better than any existing colorimeter. The room in which they worked had five different sets of lighting. These corresponded to the flourescent tubes used in the major clothing retail stores.

      No ordinary RGB monitor can show the 'fourth color' but then again the color gamut of an RGB monitor is not the same as the eye in any case. Read the documents for Adobe Photoshop and you will find them going on forever about different color gamuts for various displays - CRT, LCD and various printing technologies.

      There are a very few CRT based monitors that have a 'true color' capability, these are ultra specialist and probably can't be purchased from a catalog. They are the sort of thing the media lab would have.

      There is not that much written on four color vision in any of my neurology texts, I suspect because the ability is rare. only expressed in females and is of limited use. My guess is that just as a person without red cones can't tell the difference betwen Red and Green the effect of four color vision would be to be able to differentiate between different mixtures of pigments that we would see as the same color.

      It would be interesting to know if people with four color vision were seing the same additional wavelength. Also to know the weighting the additional color had in the vision matrix, I would suspect it would be lower than blue (13%).

      --
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  7. Colour perception by Novus · · Score: 3

    Disclaimer: I am not an eye expert.

    Essentially, human colour perception is based on the following:

    The eye has three types of colour receptors, each with different sensitivity to different wavelengths. In other words, for any incoming combination of wavelengths, the eye measures three colour intensity values.

    RGB monitors work on the principle that each of the primary colours (red, green, blue) stimulate one type of receptor much more than the others. By combining these colours suitably, we can produce the same result in the (normal) human eye (and thus the same subjective colour) as any possible wavelength distribution.

    Of course, for tetrachromats, an RGB monitor is likely to generate a totally incorrect fourth colour component, so TV must look pretty weird to tetrachromats.

    Interesting research topic: have tetrachromats study works of art to try to trace ancient tetrachromat artists (we can assume that the 4th component is wrong for artists with RGB vision).