Color Glossary H-R
Apart from the saturation and the blackness stage (or lightness), the hue is one of three properties, people sense as fundamental when perceiving colors. The HSV color model is based on these three properties. In this color model, the H is the hue which can be adapted by the program pipette. By definition, the hue is the property by which color sensations (for example red, blue or green) can be differed. A color of the same hue can vary in its saturation (for example grey) as well as in its lightness (for example pink).
HSV Color Model
In general, light is the area of electromagnetic radiation which is visible for human beings. This visible area extends approximately from a wavelength of 380 to 780 nanometer (nm). Depending on the wavelength of the light that strikes the retina, people sense different colors. Purple covers approximately wavelengths from 380 to 420 nm, blue wavelengths from 420 to 490 nm, green wavelengths from 490 to 575 nm, yellow 575 to 585 nm, Orange 585 to 650 nm and red wavelengths from 650 to 750 nm. The transitions between the colors are fluent and also the individual color areas contain various shades of color. Between blue and green there would be located the color turquoise. Under the principle of the additive color mixture the mixture of different wavelengths can result in other color impressions.
Apart from the saturation and the hue, the lightness or the blackness stage is one of three properties, people sense as fundamental when perceiving colors. The HSV color model is based on these three properties. In this color model, the V is the lightness which can be adapted easily by the program pipette. The lightness is the parameter for the total energy content or the maximum amplitude of the light or the strength of the color. The smaller the value, so pure seems the color. If this value is zero, each color is black. The opposite of the lightness is the blackness value. In the HSV color model, the lightness or the blackness value is the V (value), so that this value can be lookalike in the program pipette very well.
Today the process-color printing is a very common method used to create colorful illustrations. There the image to be printed is decomposed in the four colors cyan, magenta, yellow and black to print this colors then successively, so that, according to the subtractive mixture of color, the right color results (see CMYK color model). Theoretically, for this only the three colors cyan, magenta and yellow would be necessary. But in practice the colors are not pure enough to produce a clear black, so that black is applied as an additional color. Other, less frequent printing methods, should contain so-called decorative colors like gold, the process-color printing is not able to produce. Other pure colors like orange or green as own ink are used very seldom.