Weak current College】 【lighting technology basics.

1. visible-light
Light is electromagnetic wave to electricity transmission of radiant energy. Electromagnetic radiation in the wavelength range from only a wavelength in 380 ~ 760nm section radiation can cause light vision, called visible light. Wavelength shorter than 380nm light is ultraviolet, x-rays, gamma rays, Ray is longer than the 760nm infrared, radio waves, they have on the human eye is not a light vision, that is, invisible. Therefore, it is an objective existence of energy, and the subjective feeling of the close link.
II. classification of colors
Color can be divided into non-color and color. Non-color means white, light gray, dark gray, gray to black and white until called black series. White is the ideal of full light reflection objects, the albedo of 1; pure black is an ideal non-reflective objects, its reflectivity is 0. Therefore, non-color of white and black series represent objects on light reflectance changes. We know that light reflectance and brightness proportional, indoor white walls and ceiling can be higher brightness. Color is the white black series of colors outside. Color has three attributes: hue, lightness, and saturation, known as the three elements of color.
Hue is the color that renders out. That is the name of a different color, such as red, green, blue, etc. It and the wavelength of light. Luminosity (brightness) is the color of the bright degree. The luminosity of the different tone, even if the same hue varies due to the nature of the surface and the light intensity can also produce different shade, shades of difference. If the same is yellow, you can have a pale yellow, yellow, Brown, etc.
Saturation (chroma) indicates that the color depth (bias), or you can say that is the color of the degree of purity, bright. The higher the saturation, color is darker (concentrated), visible light in a variety of monochromatic light is the most saturated color. When spectral color white light mixed in, the more the more unsaturated. For example, red light than pink light saturation high since pink light mixed in a white light. In General, the same hue, lightness, saturation change also changed, but the luminosity of increase or decrease the saturation is reduced, only when the saturation lightness is moderate (purity) max. But gives the impression of lightness, always feel that always looks great and vivid colors.
III. RGB and color method
Red, green and blue are referred to as RGB. The three colors by mixing different proportions, can produce a variety of colors. Color mixing there are two basic methods: additive mixed and subtractive method mix.
The so-called additive mixed is when different colors of light mixed, they put in their respective share in the spectrum together to produce a new mixed colors. Indicates that the light and color blending colors. Red, green, blue three primary colors of light, when available: mixed
Red + green = yellow-green + blue = cyan light
Green + red = magenta light red + green + blue = white
If you do not mix equivalent RGB light, you can get all kinds of intermediate colors, for example:
Red light + green little = orange light
Red light + Blu-ray little = pink light [fenye]
Subtractive method mix is different color mixed, they each from the incident light in selective absorption of their spectra in the appropriate section, and produce a synthesis of color. Any two light add up as white can produce, these two complementary color on the cross that shade light (complementary colors). Such as yellow and blue are complementary colors, blue and Red Cross to complement, magenta and green mutually complementary. Therefore, yellow, cyan, magenta, blue, respectively called minus minus the red, green, that is to say three complementary colors are represented by a white minus the corresponding primary color. Therefore, yellow, cyan, magenta can be called the subtractive primaries.
When the yellow, magenta, blue three subtractive primary colors overlap by together will produce black. In the subtractive method, three subtractive primary colors of density variation respectively control the red, green and blue proportion of absorption, thus concluded that the various blend color, you can achieve and additive to the same effect by mixing.
IV. color and vision
Color conveys a sense of cold and warm feeling, distance, size and severity of the inductance, and tend to be associated, to form different psychological effects, these are long-term form of Visual habits.
Colour usually can be divided into cold, warm and neutral color (intermediate colors). Color of cold and warm colors under a variety of human Visual reactions and psychological Association Division. Red others think the heat of the fire, thereby creating a sense of warmth, known as warm. It expected the cold blue, cold, so called cool colors. Purple, green is not cool warm neutral colors. Different color can affect the size of the object's appearance. If you put some different color the same amount of objects together, in the visual perception will produce a brief white objects. Small deep black objects. In General, white objects look the most, black objects seems minimal, the yellow color of the object, followed by green, red, blue.
The color of the Visual habits also produces a sense of distance. Different colors of objects in the same distance to human visual perception. Warm colours give the feeling of moving forward, the back away from the cool colors. And color gives the sense of distance is also affected by the background color. For example, white background, the blue looks closer; the background in black, red looks lately, then Orange, yellow, green, blue, purple. The use of such features may help us to create a color stereoscopic effect, distance of illusion.
Color of interested people a Visual habits over a long period of formation. It is generally believed that white light, black, up to the heaviest. In the RGB light, green light, blue the most weight, red center. There are two primary colors of light, color, formation of mixed with light colors appear light with heavy color is heavy. Color sense of weight not only through the brightness and purity, is affected by the color in occupies an area the size of the screen. Large is heavier and more than a small area of color more attractive to people's attention.