color

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color

 [kul´er]
1. a property of a surface or substance due to absorption of certain light rays and reflection of others within the range of wavelengths (roughly 370 to 760 nm) adequate to excite the retinal receptors.
2. radiant energy within the range of adequate chromatic stimuli of the retina, i.e., between the infrared and the ultraviolet.
3. a sensory impression of one of the rainbow hues.
primary c's a small number of fundamental colors. In visual science this refers to red, green, and blue, the colors specifically picked up by the retinal cones; mixtures of varying proportions of the primary colors will yield the 150 discriminable hues of normal human vision. In painting and printing, the primary colors are red, blue, and yellow.
color vision deficiency inability to distinguish between certain colors, popularly called “color blindness.” A complete deficiency (monochromatic vision), the total inability to see colors, is rare, affecting only one person in 300,000. Much more common are the various types of partial deficiency. The most common is red-green confusion (see deuteranopia and protanopia), which affects approximately 8 million people in the United States.

Color vision is a function of the cones in the retina of the eye, which are stimulated by light and transmit impulses to the brain. It is now thought that there are three types of cones, each type stimulated by one of the primary colors in light (red, green, and blue or violet). In red-green color vision deficiency, there is a deficiency of either red or green receptors, so that the two colors do not appear distinct from each other.

Color vision is usually tested by the ishihara test with a series of pseudoisochromatic charts or plates. (See Atlas 4, Part F.) These have a letter, number, or symbol printed in dots of one color in the midst of dots of gray or other colors. The normal person can see the symbol with no difficulty, but the person with color vision deficiency cannot distinguish it from the background.

Although color vision deficiency may occasionally result from injuries, diseases, or certain drugs, most cases are hereditary. It is usually inherited by males through the mother, who carries the trait from her father although she is not color deficient herself. In some cases, if the grandfather is color deficient and the mother carries the trait, a daughter may inherit color vision deficiency, but the ratio of men to women with inherited forms is about 20 to 1. There is no known cure for color vision deficiency.
Miller-Keane Encyclopedia and Dictionary of Medicine, Nursing, and Allied Health, Seventh Edition. © 2003 by Saunders, an imprint of Elsevier, Inc. All rights reserved.

col·or

(kŭl'ŏr),
1. That aspect of the appearance of objects and light sources that may be specified as to hue, lightness (brightness), and saturation.
2. That portion of the visible (370-760 nm) electromagnetic spectrum specified by wavelength, luminosity, and purity.
[L.]
Farlex Partner Medical Dictionary © Farlex 2012

col·or

(kŭl'ŏr)
1. That aspect of the appearance of objects and light sources that may be specified as to hue, lightness (brightness), and saturation.
2. That portion of the visible (370-760 nm) electromagnetic spectrum specified as to wavelength, luminosity, and purity.
Synonym(s): colour.
[L.]
Medical Dictionary for the Health Professions and Nursing © Farlex 2012

Patient discussion about color

Q. Why is the color draining from my eyes?! When I was little I had rich shiny cobalt blue eyes! As I grew up they faded or just started to dim in color. Being partially blind you can see in my left eye the its a really light color and creamy instead of my deep blue color... Why does my eye color dim?! I didnt think going blind had anything to do with the color of my eyes changing... Or is it something else?! Please, and thank you!

A. depends on your blindness, if it is caused by your cornea changing (corneal opacity)- it'll change your eye color to a cloudy white. it can also be caused by cataract.
are those the reason of your blindness?

Q. If someone as alcoholism do there eyes change color? My husband says his work mate told him that if you’re an alcoholic your eyes can change color. As an example If you have blue eyes they become a darker blue because of something in your bloodstream?. I think my husband’s workmate is winding my husband up, or is he telling the truth?

A. That is an untruth. The color of the eyes in an alcoholic will not change color. The only thing in the eyes that will change color are the corneas (the whites of the eyes) they will turn yellow due to jaundice and probably cirrhosis of the liver. The skin will also turn yellow with the jaundice.

Q. What exactly is PPD? I heard it is a substance in hair color and that some women are allergic to it How can I know if I’m allergic to it?

A. That sounds nasty... so how can I know if i'm allergic to it or not?

More discussions about color
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References in periodicals archive ?
This 9 carat, colourless heart-shaped diamond ring sold for PS108,000 A 1920s diamond and, inset below, a pearl set Art Deco brooch.
TINTED Polysolar offers tinted photovoltaic panels for use in bus shelters, offices and hospitals, but is working on a colourless version which will be cheaper than conventional PV products
The PDS price of kerosene is Rs 9 a litre, while the colourless kerosene is sold at Rs 25- 30 a litre.
Francois Curiel, chairman of jewellery at Christie's, said, "Only three colourless diamonds of over 100 carats have ever appeared at auction, all sold in Geneva.
A"Only three colourless diamonds of over 100 carats have ever appeared at auction, all sold in Geneva,A" said Francois Curiel, chairman of jewellery at Christie's.
Most precious gems are colourless. Their colours come from impurities in the stone which act as pigmenting agents.
Brown soft drinks can quench thirst 1.129984 Colourless soft drinks can quench thirst 1.102853 Brown soft drinks have a good taste 1.081264 Colourless soft drinks have a good taste 1.136998 Brown soft drinks have a higher natural component 1.10501 Colourless soft drinks have a higher natural component 1.06383 Brown soft drinks contain artificial flavouring 0.777879 Colourless soft drinks contain artificial flavouring 1.06672 Pollution is caused in the production process of brown soft drinks 1.186848 Pollution is caused in the production process of colourless soft drinks 1.299153 Brown soft drinks contain preservatives 1.110724 Colourless soft drinks contain preservatives 1.097064 Which soft drinks are more expensive 1.083756 Which soft drinks would you choose if both have the same price?
The AMS device automatically tests colourless to near-colourless parcels.
Other Enterobcuteriacecu: such as E.coli do not express strong a-glucosidase activity and appear colourless or purple due to the uptake of crystal violet.
Lemon juice is almost colourless and the vitamin C in the lemon juice combines with iodine to form a colourless molecule.
I think I'm quite lucky in that my first colourless strand appeared aged 18.