Posts Tagged ‘photo’

Light Radiation

Optical region of the electromagnetic spectrum consists of three parts: the invisible ultraviolet light (wavelengths 10-400 nm), visible light radiation (wavelength 400-750 nm) is perceived by the eye as light and invisible infrared radiation (wavelength 740 nm – 2.1 mm). Light radiation effects on the eye and cause the sensation of color, are divided into ordinary (monochromatic) and complex. Radiation with a certain wavelength is called monochromatic. Simple radiation can not be expanded to any other color. Spectrum – a sequence of monochromatic radiation, each of which corresponds to a certain wavelength of electromagnetic fluctuations. With the expansion of white light prism in a continuous spectrum of colors in it gradually into one another.

It is generally accepted that in certain limits the wavelength (nm) radiation have the following colors: 390-440 – Purple 440-480 – Blue 480-510 – Blue 510-550 – Green 550-575 – 575-585, yellow-green – yellow 585-620 – 630-770 orange – red human eye has the greatest sensitivity to yellow-green light with a wavelength around 555 nm. There are three zones of radiation: blue-violet (wavelength 400-490 nm), green (length 490-570 nm) and red (580-720 nm in length). These zones are also a range of areas of primary spectral sensitivity of the receiver's eyes and three layers of color film. Light, emitted from conventional sources, as well as light reflected from non-luminous body, always has a complex spectral composition, ie, – is the sum of the various monochromatic radiations. Spectral composition of light – the most important feature lighting. It directly affects the light transmission when shooting in color photographic materials. Same color can be obtained by mixing various types of radiation.

Light color, have different spectral composition, but is visually perceived the same, are called metameric. Metameric colors play a big role in the practice of color filming, as the light sources that have the same color but different spectral composition, can yield significant changes in color relations for color film. It is important to consider when using mixed lighting. Same film, depending on the destination may be the most sensitivity to all parts of the spectrum.