TEACH THE CORRECT COLOR THEORY IN SCHOOLS Teachers in public schools are still teaching the wrong color theory to children.

Here is a list of reasons why this is done, why it is wrong for teachers to do it, and what must be done to correct the problem:

• REASONS THE WRONG PRIMARIES ARE STILL TAUGHT:

  Tradition dies hard. Art schools are still teaching the wrong primaries. Education schools are still teaching the wrong primaries. The "masters" used the wrong primaries. Artists worship the masters. The masters used what they could get. Early versions of the correct primaries were fugitive. They faded away under bright light, so they could not be used. The old primaries use the six basic color names taught in first grade. The correct primaries use third-grade level words. Teachers teach it the way they learned it at school. The names of some colors are too broad. Cheap boxes of crayons and paints do not contain the correct primaries. Art supply stores still sell books and color wheels showing the wrong primaries. Most art supply companies are NOT supplying materials for the correct primaries for any trade except printing. The teacher's union wants to teach the "traditional" (but wrong) primaries used by "the masters" instead of the scientifically correct primaries. Crayola even prints "Preferred by Teachers" on its sets that have all of the old primaries, but not all of the new ones. The wrong primaries do work, but cannot produce many bright colors. The gamut of colors produced is much smaller. Oil colors do work with the wrong primaries, because of properties of oil colors that do not transfer to other color media. Oil colors mix partly like light and partly like pigments. For the old primaries to work in other media, the red and blue must be desaturated (leak some white).  - The mixtures must use this leakage to be able to make the other colors. Not enough is taught about the correct primaries for teachers to learn them. Most elementary teachers are experts in the arts, language, or social studies, not science. Until the 1960s, permanent colors in the correct primaries were available only as toxic compounds.

  The old primaries

  ---

• WHY THE CORRECT PRIMARIES MUST BE TAUGHT:
  1. There are actually two sets of primaries: light, and pigment.
  2. Color photography requires knowledge of both sets of correct primaries.
  3. Full color printing requires the pigment primaries.
  4. Color TV uses the light primaries.
  5. Anyone creating colors on a computer screen needs to know the light primaries.
  6. Anyone printing colors on a color printer needs to know the pigment primaries.
  7. Inks, dyes, and watercolors definitely do not work using the old primaries.
  8. Any medium except oil paint will fail using the old primaries.
  9. Oil paint uses both types of mixing. The correct pigment primaries also work with oil paint.
  10. With any color medium except oil, the old primaries work only through leakage of imperfect pigments.

  ---

• WHAT ARE THE CORRECT NAMES OF COLORS?
  1. "Blue" covers too many colors:
     •     - Cyan, the color of robin eggs and peacock feather spots, is Isaac Newton's original blue. Call this cyan.
     •     - Teal, turquoise, robin egg blue, and peacock blue are other names for cyan.
     •     - Newton's indigo, the color of most blue ballpoint pens, is the scientists' blue. Call this blue
     •     - Today's indigo has a lot more violet than Newton's indigo.
     •     - Navy is a dark version of Newton's indigo.
     •     - Royal blue,
     •     - azure blue,
     •     - true blue,
     •     - cerulean blue, and
     •     - sky blue are in between.
  2. "Red" covers too many colors:
     •     - Magenta is not in the spectrum. It is the color of redbud trees in spring. Call this magenta.
     •     - Fuchsia is another name for magenta.
     •     - Scarlet is Newton's red. It is the color of the ripest red tomatoes. Call this red.
     •     - Cardinal red is another name for scarlet
     •     - Scarlet is the scientist's red.
     •     - Pink is desaturated red. Call this pink.
     •     - Cerise and
     •     - carmine are in between.
     •     - Vermillion is oranger than scarlet.
  3. Today, Newton would say the spectrum contains:
     •     - red,
     •     - orange,
     •     - yellow,
     •     - green,
     •     - cyan,
     •     - blue, and
     •     - violet.

  ---

• LET'S STANDARDIZE COLOR NAMES:
  

  • We need more precise colors names, so we can better describe them.
    Here is a suggestion of hue names, equally spaced around the color wheel
    * = Primary color
    1.     - magenta*,
    2.     - cerise,
    3.     - red*,
    4.     - orange,
    5.     - yellow*,
    6.     - leaf,
    7.     - green*,
    8.     - aqua,
    9.     - cyan*,
    10.     - azure,
    11.     - blue*, and
    12.     - violet.

  ---

• STOP NAMING COLORS WRONG:
  

  • Part of the reason people believe in the old color system is the wrong usage of names for colors.
    1.           This is magenta. It is very different from red or pink.
                 It is an equal mixture of red and blue light.
                 Do not call it red, pink, or hot pink.
        
    2.           This is pink.
                 It is a mixture of strong red with weakened green and blue.
                 Do not call other colors pink
        
    3.           This is red.
                 It consists of only red light.
                 Do not call other colors red.
        
    4.           This is cyan.
                 It is an equal mixture of green and blue light.
                 Do not call it blue. It is not blue.
        
    5.           This is blue.
                 It consists of only blue light.
                 Do not call other colors blue.
        

    Part of the problem is that the old primary system (below), used with oil paints, produced these colors through abnormal mixing:

    1.        
               The red pigment most often used, mixed with white, thins out to make a lighter
               magenta. But they called it pink, because of the following:
              
        
    2.        
               A different red pigment mixes with white to make
               pink. This is the real pink.
              
        
    3.        
               The blue most often used mixes with white to produce
               cyan. But they called it blue.
              
        

    Note that these are the results of the varying concentration effects of pigments with sloped filter curves. It works in oil paints, but not with any other color medium.

  ---

• WHAT ARE THE OLD PRIMARY COLORS?
  

  Old Primaries
   

  

  Old Color Wheel
   

  1. The old artist's primaries are:
     •     - Red, which is scarlet.
     •     - Yellow, which is the color of daffodils, and
     •     - Blue, which is Newton's indigo.
  2. Greens and violets are produced only where the pigments leak other colors.
  3. Mixing transparent pigments in old primaries makes dull greens and violets.
  4. The three pigments cannot mix together to make black. Such a mixture makes brown instead.
  5. These colors are found in a Crayola™ box of 8 crayons.
  6. Most materials for teaching colors at schools use these primaries.
  7. Four-color school watercolor paint boxes are made with these colors, plus black.
  8. Many toys made in these colors are mistakenly labeled "educational."
  9. These primaries work better for oil colors than for other color media, because:
     • The blue usually used turns to cyan at low concentrations.
     • The red usually used turns to magenta at low concentrations.
     • Opaque pigments mix using light primaries, but with darker results.
  10. A toy top was made that attempted to mix these colors like light.
       - The greens and oranges were almost white. With pure pigments, the green would have been white.
  11. The three-circle mixing diagram and the color wheel at right show how dark the greens and violets are when pigments are mixed.
  12. The colors on the color wheel are not standard computer colors. Magnifying the image shows that they are mixed pixel-wise.
  13. Notice that two of the primaries are darker colors, and the third is the lightest color. It makes no sense.

  ---

• WHAT ARE THE CORRECT PIGMENT PRIMARY COLORS?
  

  New Primaries
   

  

  New Color Wheel
   

  1. The correct pigment primaries are:
     •     - Magenta (fuchsia), which is the correct pigment primary "red,"
     •     - Yellow, which is the color of daffodils, and
     •     - Cyan (teal), which is the correct pigment primary "blue." It was "blue" to Newton.
  2. Rich greens, blues, and violets are possible
  3. Black can be made by mixing equal amounts of the three primaries.
  4. Only the yellow is found in a Crayola™ box of 8 crayons.
  5. The Crayola™ colors Magenta, Yellow, and Teal are the correct primaries.
  6. The colors in the 4-pack of Play-Doh™ are the correct primaries.
  7. The secondary colors of pigment are the light primaries (below).
  8. Look at colored comics with a magnifier and see dots of these pigment primaries.
  9. Full color printing is done with these primaries.
  10. Ink jet color printers use these primaries.
  11. These primaries may or may not work with certain oil pigments. Color must not be made through the slope of the response of one pigment
  12. These primaries also work with oil paints, if the proper paints are bought.
  13. Mixtures made using magenta, yellow, and cyan work better than mixtures of other colors if the light source is nonlinear, such as:
      • Old-Style Fluorescent Lamps
      • Compact fluorescent Lamps
      • High Intensity Discharge Lamps
      • High Pressure Sodium Vapor Lamps
      • White Light Emitting Diodes (LED)
  14. The three-circle mixing diagram and the color wheel at right show how bright the greens and violets are.
  15. The color wheel is the same one used for the light primaries.
  16. The colors on the color wheel are the standard computer colors. Magnifying the image shows no pixel-wise mixing.
  17. The correct pigment primaries are 120 degrees apart on the new color wheel. Start at yellow.
  18. The three pigment primaries are the three lightest pure hues.
  19. Two of the correct pigment primaries do not even exist on the old color wheel.

  ---

• WHAT ARE THE LIGHT PRIMARY COLORS?
  

  Light Primaries
   

  

  New Color Wheel
   

  1. The light primaries are:
     •     - Red, which is scarlet.
     •     - Green, which is the color of most leaves, and
     •     - Blue, which is Newton's indigo.
  2. Overlapping beams of different colored light mix using these primaries.
  3. White can be simulated by mixing equal amounts of the three primaries.
  4. Tiny nonoverlapping dots of color mix in this way.
  5. All three colors are found in a Crayola™ box of 8 crayons, although that information is not useful for mixing light.
  6. Reflective glitter mixes like light mixes.
  7. The secondary colors of light are the pigment primaries.
  8. These colors are used in color television. Look at a color TV screen with a magnifier to see dots or stripes of light primaries.
  9. A spinning disk with sectors of light primaries on it mixes in this way.
  10. That toy top mentioned above should have used the light primaries.
  11. The three-circle mixing diagram and the color wheel at right show how bright the greens and violets are.
  12. The color wheel is the same one used for the correct pigment primaries.
  13. The colors on the color wheel are the standard computer colors. Magnifying the image shows no pixel-wise mixing.
  14. The light primaries are 120 degrees apart on the new color wheel. Start at red.
  15. The three light primaries are the three darkest pure hues.

  ---

• WHAT ARE THE PSYCHOLOGICAL PRIMARY COLORS?
  

  New Color Wheel
   

  1. The psychological primaries are:
     1.     - cerise
     2.     - yellow
     3.     - aqua
     4.     - blue
  2. These primaries are generated by the yellow-blue and red-green bipolar cell encodings in the retina.
     1. Cerise has a neutral yellow-blue output signal, and a maximal red output of the red-green signal.
     2. Yellow has a neutral red-green output signal, and a maximal yellow output of the yellow-blue signal.
     3. Aqua has a neutral yellow-blue output signal, and a maximal green output of the red-green signal.
     4. Blue has a neutral red-green output signal, and a maximal blue output of the yellow-blue signal.
  3. These primaries can not be used for color mixing.
  4. Two of the four colors are found in a Crayola™ box of 8 crayons, although that information is not useful for mixing colors.
  5. The color wheel is the same one used for the correct pigment primaries and the light primaries.
  6. The psychological primaries are 90 degrees apart on the new color wheel. Start at yellow.

  ---

• WHAT IS THE COLOR MAP?

  The Commission Internationale de l'Eclairage (CIE - the International Commission on Illumination) experimentally determined the color map at the right as a diagram of the only colors the normal human eye can see, not counting black and darker versions of the same colors (which would be under the map). The lower image is the map seen with the z-axis perpendicular to the page. The upper image is an isometric projection of the map with the plane x + y + z = 1 in the plane of the page and the zero origin directly under the 6500 K white point. The pure spectral hues go around the curved edge from red through green to blue. The wavelengths in nanometers (nm) are on the curve. The straight line connects red to blue through the nonspectral hues (all mixtures of red and blue). x is the portion of the observed color that is red. y is the portion of the observed color that is green. z is the portion of the observed color that is blue. It is perpendicular to the page in the lower image. The top surface of the map (the visible portion in the diagram) is the plot of the plane: x + y = z = 1 White is in the center, at the location x = .33; y = .33; and z = .33. It is at the color temperature of 6500 K. Note that all visible light wavelengths stimulate at least two cone cell types. This is because other parts of the optic system block light with wavelengths shorter than 380 nm and longer than 770 nm. Thus, the case where one cone cell type is stimulated exclusively is not possible. This explains the fact that no part of the colored area of the map reaches a corner of the graph. The red cones are also slightly sensitive to blue and violet, explaining why the blues have higher x values than some greens (see the spectral plots below). It also explains why we see all of the hues as making a circle of pure colors, so we have a color wheel. Green cones are also partly sensitive to red, explaining the nonzero Y value at the red end of the spectrum. The regions outside the colored area of the map are impossible colors, because they would require stimulating the cone cells in the eye in ways that real light can not do. The curved line through the center is the Planckian Locus, the plot of colors produced by a black body heated to various temperatures. The temperatures are given in Kelvins (K). The color temperature of a neutral white is 6500 K. Color TV and computer monitors cannot correctly produce some of the colors in the color map (and they do not reproduce properly here) because the primary colors chosen for the NTSC system (and all color monitors) correspond to the wavelengths 610 nm (red), 540 nm (green), and 470 nm (blue). The gamut (range) of colors a color monitor can reproduce is thus limited to the colors on or inside the triangle connecting these three points on the spectral perimeter (the triangle with lines A and D as sides). Any color outside the triangle cannot be reproduced on a color monitor (including this one). These colors were chosen to sacrifice colors in the cyan area to make flesh tones come out more accurately. Two proposals for including more colors on monitors exist: One proposal adds another primary at 510 nm. This covers most of the visible colors. The extra primary could be automatically selected from existing signals, using heuristics based on the values of x and y in the existing color signal. The gamut is the convex quadrilateral including lines B and D as sides. The other proposal adds yellow at 575 nm, and changes the green primary to 510 nm. Monitors have been produced with these primaries. These also use heuristics to select the primaries used for each color. The gamut is the quadrilateral including lines C and D as sides. The white triangle is the gamut of colors visible when illuminated with many brands of white LEDs.

  Isometric Projection (axes shown 120° apart) Orthographic Projection (z-axis perpendicular to page)

  ---

• WHY DOES IT WORK?
  

  Receptor Cell Sensitivities
   

  

  Color Encoding Matrix
   

  1. The human eye has three kinds of light receptors for color, plus another for night vision.
  2. The receptors are individually sensitive to the three light primaries:
     • The red receptor is sensitive to:
           red,     orange, and     yellow.
     • The red receptor is somewhat sensitive to:
           green and     violet.
     • The green receptor is sensitive to:
           yellow,     green, and     cyan.
     • The green receptor is somewhat sensitive to:
           orange and     azure.
     • The blue receptor is sensitive to:
           cyan,     blue, and     violet.
     • The blue receptor is partially sensitive to:
           aqua.
     • The rod receptor     for night vision is sensitive to all colors except red. It is most sensitive to cyan and green, and least sensitive to orange. But since it is not color-encoded, it produces a black-and-white image.
  3. The cyan gap in human vision is caused by the low point where the curves of the green and blue receptors meet on the graph above. It is not a true gap, but a reduction in sensitivity in the cyan region.
     • This usually appears when a human is looking at a projected spectrum,
     • In this case, the cyan region of the spectrum looks     dark blue green, instead of     cyan.
     • Notice how much lower cyan is on the response curves (45%) than any other hue is.
     • With an equal-energy spectrum, cyan looks dimmer than the other colors.
     • The rods do not contribute to cyan response because they are not encoded for color.
  4. The color matrix explains some behaviors of the human vision system.

     The color information is encoded in the retina of the eye, providing a brightness signal and two color signals, rather than a signal for each primary color:

     • The luminance signal (LUM) is the overall brightness at one point on the retina.
     • Luminance is the sum of the red, green, blue cone and the rod output levels.
     • Yellow is the sum of the output levels of the green and red cones.
     • The B-Y signal gives the difference between the blue level and the yellow level.
     • The G-R signal gives the difference between the green level and the red level.
     • The color matrix gives the following outputs:
       • The vertical axis is the B-Y axis.
       • The horizontal axis is the G-R axis.

       Matrix Output:      Expanded G-R:             Y                                R       G                             B

     • The four psychological primaries (Cerise, Yellow, Aqua, Blue) are caused by the color matrix.
     • A psychological primary is where one difference is zero while the other is a saturated color.
  5. Other colors cause multiple receptors to have stimuli:
     •     Yellow light equally stimulates the     red and     green receptors.
     •     Orange light stimulates the     red receptor more than the     green receptor.
     •     Cyan light equally stimulates the     green and     blue receptors.
     •     White light is a mix of all colors, and stimulates all three receptors equally.
     •     Magenta light is not in the spectrum. It an equal mix of     red and     blue light, and stimulates those receptors.
     •     Black is the absence of light, and stimulates no receptors.
     •     Pink is a mix of all colors, but stimulates the     red receptors more than it does the     green and     blue receptors.
       Do not confuse pink with magenta.
  6. Mixtures of primary lights stimulate the receptors the same as other colors:
     • A mixture of     red and     green light stimulates both receptors, simulating     yellow light.
     • A mixture of     green and     blue light stimulates both receptors, simulating     cyan light.
     • A mixture of     red and     blue light stimulates both receptors, making     magenta light.
     • A mixture of     red,     green, and     blue light stimulates all receptors, simulating     white light.
     • A mixture of strong     red and weak     green light simulates     orange light.
     • A mixture of strong     red, weak     green, and weak     blue light stimulates all receptors, simulating     pink light.
     • This effect makes color television and color photography possible.
  7. Pigments remove colors from the light falling on them:
     •     White pigment reflects all colors, appearing white.
     •     Magenta pigment absorbs     yellow,     green, and     cyan light.
       Removing those colors from white leaves     red,     blue, and     violet, making     magenta light.
     •     Yellow pigment absorbs     cyan,     blue, and     violet light.
       Removing those colors from white leaves     red,     yellow, and     green, making     yellow light.
     •     Cyan pigment absorbs     red and     yellow, and some of the     violet light.
       Removing those colors from white leaves     green,     cyan, and     blue, making     cyan light.
  8. Mixtures of primary pigments remove the colors removed by each pigment:
     • Mixing     magenta and     yellow pigments removes all colors except     red, leaving red light.
     • Mixing     yellow and     cyan pigments removes all colors except     green, leaving green light.
     • Mixing     magenta and     cyan pigments removes all colors except     blue, leaving blue light.
     • Mixing     magenta,     yellow, and     cyan pigments removes all colors, leaving     no light. It appears black.
  9. Pigments can be diluted, allowing some light to leak through:
     • Mixing diluted     magenta and full-strength     yellow pigments makes     orange.
     • Mixing diluted     magenta and diluted     yellow pigments makes     pink.
     • Mixing full-strength     magenta and     yellow pigments with diluted     cyan pigment makes     brown.
     • Mixing equally diluted     magenta,     yellow, and     cyan pigments makes     gray.
     • Mixing full-strength     magenta and diluted     cyan pigments makes     violet.

  ---

• 	Old Primaries	Light Primaries	Pigment Primaries
  Used For Light
  Used For Pigments
  Used With Oil Paint

  WHAT HAPPENS IF WRONG PRIMARY COLORS ARE USED?
  1. If the wrong primaries are used, the wrong colors appear.
  2. Using the wrong primaries gives a smaller gamut of colors.
  3. Notice the complete lack of greens with the old primaries.
  4. Colors are pastel with the wrong light primaries.
  5. Colors are dark with the wrong pigment primaries.
  6. Wrong primaries must be desaturated to get more colors.
  7. Color-sensitive pigments in the eye dictate the primaries to use.
  8. Light primaries are complements of pigment primaries.
  9. Light primaries are pigment secondaries.
  10. Pigment primaries are light secondaries.
  11. Oil paints partly mix like light and partly mix like pigment.
  12. Even oil paints work better with the pigment primaries.

  ---

• Different receptor types give different light primary colors:

  HUMAN EYE TYPE	LIGHT PRIMARIES	PIGMENT PRIMARIES
  normal human	- red, green, blue	- magenta, yellow, cyan
  protanomalic	- orange, green, blue	- magenta, chartreuse, cyan
  deuteranomalic	- red, yellow, blue	- magenta, orange, aqua
  protanopic	- green, blue	- green, blue
  deuteranopic	- orange, blue	- orange, blue
  tritanopic	- red, green	- red, green
  tetartanopic	- cerise, aqua	- cerise, aqua
  monochromatic	- blue	- black
  cone-blind (and normal night vision)	- cyan	- black
  ANIMAL EYE TYPE	LIGHT PRIMARIES	PIGMENT PRIMARIES
  cat	- red, green, blue	- magenta, yellow, cyan
  some fish	- red, green, blue	- magenta, yellow, cyan
  dog	- yellow, cyan	- yellow, cyan
  most nocturnal animals	- blue and rods	- black
  some birds	- red, yellow, cyan	- purple, orange, green
  other birds	- yellow, cyan, violet, UV	(we can't see or name them)
  a few birds	- red, green, blue, violet, UV	(we can't see or name them)
  most insects	- green, violet, UV	- green-UV, cyan, violet-UV
  spiders	- green, blue, violet, UV	(we can't see or name them)
  bees and butterflies	- yellow, green, blue, violet, UV	(we can't see or name them)
  pit vipers	- infrared, blue	- infrared, blue
  PRIMATES	LIGHT PRIMARIES	PIGMENT PRIMARIES
  old-world	- red, green, blue	- magenta, yellow, cyan
  new-world, 1/2 females*	- red, green, blue	- magenta, yellow, cyan
  new-world, 1/2 males, 1/4 females*	- green, blue	- green, blue
  new-world, 1/2 males, 1/4 females*	- orange, blue	- orange, blue
  nocturnal prosimians	- blue and rods	- black
  HUMAN EYE 4-COLOR	LIGHT PRIMARIES	LIGHT SECONDARIES**
  normal human set 1	- red, leaf, aqua, blue	- magenta, yellow, green, cyan
  normal human set 2	- red, yellow, aqua, blue	- magenta, orange, leaf, cyan

  * The X-chromosome has only one space for a color cone gene, and can take either the red or the green cone gene, but not both. The Y-chromosome can not accept a color vision gene. So males must be dichromats, but females can be either dichromats or trichromats. The dichromatic females receive two copies of the same cone gene.

  ** The pigment primaries are those of normal human vision. These are attempts to make a better color monitor that covers more colors, by covering more of the green curve in the CIE map.

  ---

LINKS:

1. About Human Color Vision
2. Human Color Vision Defects
3. Color Blindness and Traffic Signals
4. Other pages on LIGHT BULBS, SPECTRA, and HUMAN VISION
5. UFO PAGE
6. Home