Color & Vision

See the "Color & Vision" pull down menu at the top of this page or link to the articles below.

Sore eyes

  Color and Vision Matters
  Can colors irritate your eyes? See RED!


  How the Eye Sees Color
  An easy explanation of color vision

inside the eye

 Look Inside the Eye
  Color detection equipment

Green stop sign

  Color & Accident Matters
  Did the color make you do it?

Color Blind test

    What is Color-Blindness
  Examples & sample tests for color-blindness

Mouse and colors
  Color Vision for Mice
  About a gene that gives animals color vision.

  How Animals See Color

Are Black and White Colors?

  Are Black and White Colors?
   Answers from design and science

Why does color matter?

   Why Color Matters
  How color affects vision and the brain



The Color Blind Shopper

Colorcom - Color Pschology Experts

Color & Vision Matters

Color Matters

The human eye can see 7,000,000 colors. Some of these are eyesores. Certain colors and color relationships can be eye irritants, cause headaches, and wreak havoc with human vision. Other colors and color combinations are soothing. Consequently, the appropriate use of color can maximize productivity, minimize visual fatigue, and relax the whole body.

Which color is the most irritating?

yellowYellow, pure bright lemon yellow is the most fatiguing color. Why? The answer comes from the physics of light and optics. More light is reflected by bright colors, resulting in excessive stimulation of the eyes. Therefore, yellow is an eye irritant. Some claim that babies cry more in yellow rooms, husbands and wives fight more in yellow kitchens, and opera singers throw more tantrums in yellow dressing rooms. However, these reports  have not been scientifically proven.  

In practical application, bright yellow - when used in large areas, will irritate the eyes. Therefore, do not paint the walls of an office (or any critical task environment) yellow. Note: Lighter shades of yellow can be comforting and cheerful.

Also, beware of  bright yellow legal pads  (but this may give you a jolt and temporarily wake your brain up) and do not use yellow as a background on your computer monitor.

On the other hand, since yellow is the most visible color of all the colors, it is the first color that the human eye notices. Use it to get attention, such as a yellow sign with black text, or as an accent. Have you noticed yellow fire engines in some cities?

Finally, yellow is a wonderful color, the most cheerful of the spectrum. And yellow is a symbol of the deity in many global religions.

Some tips for practical application:

Notice the difference between a yellow of the purest intensity and a softer tint. Also the size of the area that any color occupies determines the color effect. For best results, use softer tints of the hue or small quantities. A little bit of color goes a long ways.

The Meanings of Yellow
Find out more about yellow: "The Meanings of Yellow"

Color Consultation for Branding and Marketing

See red?

redPerhaps you've used this phrase to mean that you're so angry that you literally see red. Here's a test to see if you really see red. And it will be a bit of magic because you will see the invisible.

1. Make sure the image below fills your computer screen.
2. Look at the image at a distance of 12 inches or 30 centimeters from the screen.
3. Stare at the black dot in the middle of the red rectangle for 30 seconds. Keep your focus on the black dot or the test will not work.
4. After 30 seconds, shift your focus to the black dot in the middle of the white rectangle. Once again, you must focus on the black dot in the middle of the white square or this will not work.


red test

 Did you see red? Probably not. What did you see?

You are not hallucinating. You saw an "after image" and there is a very scientific explanation for it: Your eye is filled with 250,000 color decoding cones. The 83,000 cones that are used to decode red became fatigued and over stimulated when you focused on the red rectangle. Consequently, the opposing cones kicked into action. You probably saw blue or bluish green, somewhat like transparent bluish light or cellophane on the white area. (If you saw nothing, reread the instructions and take the test again.)

The operation of the eye is largely muscular and any excessive activity will tire it out. Note: Some scientists have noted that after-images are caused by a depletion of certain chemicals in the rods and cones of the eye, which are sensory cells, not muscles.

Here are some practical examples of how colors cause visual fatigue:
Let's assume that you work on an assembly line and sort red pills 8 hours a day. If the work surface is white, you'll fatigue the eyes and get an after image. If you use a soft muted teal as the work surface color, you'll maximize visual efficiency. "After image" will occur with any color. Imagine what would happen if you were in a monochromatic blue interior. Which color would your eyes be hungry for?

What happens when chickens see red?

A company* that markets red contact lenses for chickens (at 20 cents a pair), points to medical studies showing that chickens wearing red-tinted contact lenses behave differently from birds that don't. They eat less, produce more and don't fight as much. This decreases aggressive tendencies and birds are less likely to peck at each other causing injury. A spokesman said the lenses will improve world egg-laying productivity by $600 million a year.

(Perhaps everything looks red and they cannot distinguish combs, wattles, or blood. Or ...perhaps the chickens are happier because they're viewing the world through rose colored glasses.)

* Animalens Inc. of Wellesley, Mass
If you don't believe this, read the facts! Click here.

sq chh home fandeck 280

Another eye test

Once again, follow the same instructions:

1. Make sure the image below fills your computer screen.
2. Look at the image at a distance of 8-12 inches or 20-30 centimeters from the screen.
3. Stare at the black dot in the middle of the white star for 30 seconds. Keep your focus on the black dot or the test will not work.
4. After 30 seconds, shift your focus to the black dot in the middle of the white rectangle. Once again, you must focus, you absolutely must hold your focus on the black dot in the middle of the white square after the 30 seconds pass, or this will not work.



black and white star test

What did you see?

This time the issue is color contrast. The difference between white and black creates excessive muscular activity which fatigues the eye. The same thing happens when you try to read white papers on a black or dark desk. You should have seen a grey star on the white square. If you didn't, reread the instructions, and take the test again. Make sure you are close enough to the image.

Here are some practical examples:
If you're in a corporate office, take this theory into the conference room or corporate boardroom. In many instances, you'll find a dark surface, and oftentimes highly lacquered. It may have a high tech corporate look but it will not be conducive to the work at hand. As for your private residence, the kitchen is a critical task environment and the same theories apply.

The scientific explanation is as follows:
White surfaces reflect about 80% of the light, black 5%.
We take these two percentages, divide 80 by 5 and we get a 16:1 Light Reflectance ratio. The Illuminating Engineering Society (IES) in the United States recommends a maximum ratio of 3:1 for a visual task and the adjacent surroundings.

If you're in a commercial situation, consider hiring a professional interior designer who focuses on both visual ergonomics and aesthetics to create a more positive and productive interior environment.


 You might also be interested in this page at Color Matters

How does color affect taste?

How does color affect taste? Which color might help you lose weight? Don't miss this interesting article: How Color Affects Taste and Smell

Open the door to color. Transform your home, office, logo and much more.

How the Eye Sees Color


Color originates in light. Sunlight, as we perceive it, is colorless. In reality, a rainbow is testimony to the fact that all the colors of the spectrum are present in white light. As illustrated in the diagram below, light goes from the source (the sun) to the object (the apple), and finally to the detector (the eye and brain).


Diagram of how the eye sees color

1. All the "invisible" colors of sunlight shine on the apple.

2. The surface of a red apple absorbs all the colored light rays, except for those corresponding to red, and reflects this color to the human eye.

3. The eye receives the reflected red light and sends a message to the brain.

The most technically accurate definition of color is:
"Color is the visual effect that is caused by the spectral composition of the light emitted, transmitted, or reflected by objects."

Reprinted with permission from Color Logic
© Copyright 2004, all rights reserved


Legal permission was granted for this page to be  translated into Russion to spread the good news about color around the globe. See How the Eye Sees Color in Russian.

Encyclopedia of Color Design

Color & Accident Matters


car accident

The color made me do it! You are the judge.

"I didn't intend to break the traffic rules," he stated. "It's the stop sign. It's green and it should be red and I went right through it." What's your verdict?

Colors do affect our actions and reactions in traffic as well as in interior environments. Colors can create conditions that can cause fatigue, increase stress, decrease visual perception, damage eyesight, increase possible worker errors, and negatively affect orientation and safety.

The healthy, accident-free workspace is an issue that is being redefined by new facts. The "sick building syndrome" has made us aware of the toxic effects of many interior elements. Ergonomics has made us aware of furniture which can help to avoid strain and injury. Of equal importance is the role that color plays in creating accident-free, physically and visually sound interiors. Incorrect use of colors and patterns in interior and exterior environments can create visual impairments and cause serious accidents.

Here are some examples of color as the cause of accidents and injuries in interior and exterior environments:


factory worker using a lever

1. A factory worker reaches for the emergency "STOP" lever on a machine. It is improperly color-coded and does not conform to OSHA regulations (US). He reaches for the wrong one. (OSHA coding for emergency stop bars devices is red.)

slip and fall on carpet

An elderly man is walking down a hallway in a hotel. The hall is carpeted with a brightly colored large pattern. He perceives the colors to be "jumping up" at him (because most bright colors are perceived to be moving forward),  his motor responses respond, and he trips and falls to the floor.

worker carrying a heavy object

3. A dock worker carrying a box on a stepped platform, slips and falls because the edge of the work area is not distinctly marked.

eye fatigue from computer

4. An office worker suffers constant headaches and visual fatigue after working at a computer terminal. The bright yellow wall color behind the monitor and glare from surrounding fixtures are straining her eyes. After several years, her once perfect vision is impaired.

visual distraction

5. An assembly line worker is distracted by a brightly colored object within her field of vision. She loses concentration and injures her hand.


Color Consultation for Legal Disputes - Colorcom


Color Vision for Mice


mouse and color wheel

Mice, like most mammals, are color-blind. They see a very limited number of colors - similar to what some humans with color blindness see.

Scientists (at John Hopkins and the University of California at Santa Barbara) gave mice a special gene that completely changed the animal's color vision. In basic terms, humans have trichromatic color vision. We have three types of cells in our eyes. These absorb blue, green, and red light. Since most mammals have only two types of cells, they can only see a fraction of the colors that humans see. Simply by introducing a gene, scientists discovered that the mice could distinguish colors as never before.

Researchers conducted tens of thousands of tests using colored panels. Mice received a drop of soymilk as a reward when they correctly identified which panel differed from the other two. Normal mice failed to discriminate yellow versus red lights; the genetically altered mice demonstrated their new color vision by choosing the correct panel in 80 percent of the trials.

The evolution of color vision has been a topic of intensive study for more than three decades. The new research is the most definitive yet in shedding light on the first steps that led to the emergence of color vision found today in most primates, including humans.

"What we are looking at in these mice is the same evolutionary event that happened in one of the distant ancestors of all primates and that led ultimately to the trichromatic color vision that we now enjoy." Jeremy Nathans


According to scientists, this reveals significant information about the evolution of color vision. Their findings also have implications for other senses such as smell and taste. Expanding the range of other sensory input could extend the range of information that an animal senses. It could alter behavior and much more.

Furthermore, the research points to the possibility of correcting color-blindness in humans and perhaps add gene variants to enhance our color vision. (Note: Researchers have already indentified some people who appear to have four different color receptors - tetrochromats. Some animals have even more.)


A study published in the March 23, 2007, issue of the journal Science, Howard Hughes Medical Institute

Genetic Studies Endow Mice with New Color Vision
Making mice with enhanced color vision


Some facts about color vision

Eye with color visionHumans, apes, most old world monkeys, ground squirrels, and many species of fish, birds, and insects have well-developed color vision. However, it's worth noting that 7 or 8 percent of human males are relatively or completely deficient in color vision.

Humans with the most common form of color-blindness and mammals with poor color vision are unable to differentiate between reds and greens. They see the world as a blend of blues, yellows, and greys.

Mammals with limited color vision or none at all include mice, rats, rabbits, cats, and dogs. Nocturnal animals - such as foxes, owls, skunks, and raccoons - whose vision is specialized for dim light seldom have good color vision. By comparison, humans are color-blind in dim light.

Source: David Hubel's Eye Brain and Vision


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