Green in Optics and Color Theory
| Color | Frequency | Wavelength |
|---|---|---|
| violet | 668–789 THz | 380–450 nm |
| blue | 606–668 THz | 450–495 nm |
| green | 526–606 THz | 495–570 nm |
| yellow | 508–526 THz | 570–590 nm |
| orange | 484–508 THz | 590–620 nm |
| red | 400–484 THz | 620–750 nm |
Green is the color you see when you look at light with a wavelength of roughly 520–570 nanometers.
It is one of the three additive colors, along with red and blue, which are combined on computer screens and color televisions to make all other colors.
In the subtractive color system, used in printing, it is not a primary color, but is created out of a mixture of yellow and blue, or yellow and cyan;
On the HSV color wheel, also known as the RGB color wheel, the complement of green is magenta; that is, a purple color corresponding to an equal mixture of red and blue light. On a color wheel based on traditional color theory (RYB), the complementary color to green is considered to be red.
The perception of greenness (in opposition to redness forming one of the opponent mechanisms in human color vision) is evoked by light which triggers the medium-wavelength M cone cells in the eye more than the long-wavelength L cones. Light which triggers this greenness response more than the yellowness or blueness of the other color opponent mechanism is called green. A green light source typically has a spectral power distribution dominated by energy with a wavelength of roughly 487–570 nm.
In additive color devices such as computer displays and televisions, one of the primary light sources is typically a narrow-spectrum yellowish-green of dominant wavelength ~550 nm; this "green" primary is combined with an orangish-red "red" primary and a purplish-blue "blue" primary to produce any color in between – the RGB color model. A unique green (green appearing neither yellowish nor bluish) is produced on such a device by mixing light from the green primary with some light from the blue primary.
By contrast in process color printing, a subtractive color system, green can be produced via a mixture of cyan and yellow ink, and in traditional color theory, green is produced by mixing yellow and blue paint.
Green is complementary to a purplish red or reddish purple color, in both additive and subtractive mixtures, and in simultaneous contrast effects and afterimages.
The sensitivity of the dark-adapted human eye is greatest at about 507 nm, a bluish-green color, while the light-adapted eye is most sensitive about 555 nm, a yellowish-green color. Human eyes have color receptors known as cone cells, of which there are three types. In some cases, one is missing or faulty, which can cause color blindness, including the common inability to distinguish red and yellow from green, known as deuteranopia or red–green color blindness. Green is restful to the eye. Studies show that a green environment can reduce fatigue.
Read more about this topic: Greenishness, In Science
Famous quotes containing the words green, color and/or theory:
“You know, if this is Venus, or some other strange planet, we’re liable to run into some high-domed characters with green blood in their veins who’ll blast at us with their atomic death rayguns, and there we’ll be with these—these poor old-fashioned shootin’ irons.”
—Edward L. Bernds (b. 1911)
“The most refined skills of color printing, the intricate techniques of wide-angle photography, provide us pictures of trivia bigger and more real than life. We forget that we see trivia and notice only that the reproduction is so good. Man fulfils his dream and by photographic magic produces a precise image of the Grand Canyon. The result is not that he adores nature or beauty the more. Instead he adores his camera—and himself.”
—Daniel J. Boorstin (b. 1914)
“We commonly say that the rich man can speak the truth, can afford honesty, can afford independence of opinion and action;—and that is the theory of nobility. But it is the rich man in a true sense, that is to say, not the man of large income and large expenditure, but solely the man whose outlay is less than his income and is steadily kept so.”
—Ralph Waldo Emerson (1803–1882)