Light color and spectrum analysis

Performing arts stage lighting color is extremely rich and varied, some use large white lighting gaffer stage scenery, the original law flavor, very interesting; some gaffer like to use colored light, a large area of staining, stippling small, especially flipping the audience's attention .

Stage lighting color comes mainly from two ways: electro-optic light color and original electric light (or lamp) additional filter caused by light color.

1, the electric light source color and spectral analysis

Stage lighting in all kinds of electric light lit Baise, Liang Yan scene, their colors are unified crown with the corresponding color temperature or correlated color temperature, use light color temperature blackbody radiation source expressed in quantitative scientific digital articulate physiological , the amount of psychological vision is a big step forward. Figure 1 is a spectral radiant blackbody radiation temperature at various relative energy released graph shows spectra interpretation:

1. blackbody (thermal radiation source) radiation hit different temperatures, relative spectral radiant energy released is different, the higher the temperature, the greater the total relative energy radiation.

2. spectrum at each temperature curve is relatively energy released continuous, uninterrupted.

3. Temperature is not the same, the relative spectral radiation energy is released, the red, the radiation energy is also different than the blue band. The lower the radiation temperature, red, blue radiation energy ratio greater, the more its light color warmer, reddish, referred to as the color temperature of the light source is low; the higher the temperature radiation, its blue, red ratio, the higher the radiation energy, the light color the more partial white, bluish, referred to as the color temperature of the light source is high. Color temperature meter is based on this principle of optical manufacturing.

Stage lighting power source are two major categories: thermal radiation source and the gas discharge light source. Attributable to thermal radiation source categories are: halogen lamps (halogen), steamed aluminum foam, incandescent, gas discharge lamp attributable to the class are: xenon lamp, metal halide, fluorescent lamps and the like. After they have their different relative spectral radiation energy distribution, stimulate the human eye, often showing a different color of light effects. But there are also "metamerism" phenomenon, that is, different relative spectral energy released light can also cause the same color vision, or say the same light color may also have different relative spectral energy distribution.

A fluorescent lamp (3200K) and halogen bulbs (3200K) relative spectral energy distribution of a fluorescent lamp (5500K) and daylight (5500K) relative spectral energy distribution. Interpretation of these four lines, can lead to insights as follows:

1. Hsi different light have different relative spectral energy distribution, showing different light colors are marked with different color temperatures 3200KT 5500K.

2. metamerism phenomenon exists objectively. Two sources with the same color temperature, but both the relative spectral energy distribution are not identical.

3. The color temperature of 3200K light source spectral distribution in blue, red relatively small proportion of the energy, and the color temperature of 5500K light source spectral distribution in blue, red relative energy ratio has improved so much.

4. The tungsten halogen lamp with daylight spectral energy distribution curve is relatively continuous and smooth transition, while the fluorescent lamp spectral distribution curve has several relative energy peaks, sandwiched between several intense line spectrum of radiation, which is one of several characteristic lines phosphor chemical elements.

   While fluorescent and halogen lamps or sunlight corresponding spectral energy distribution communicated to substantially the same curve, but the details of the spectral distribution are still differences, some differences in the band is still very large. Although they are marked with the same color temperature of 3200K or 5500K, but still behind in its implicit distinction between the two:

(1) halogen lamps, the sun and the black body, are thermal radiation source whose chromaticity point is the black body locus on the chromaticity diagram, and different fluorescent and bold, is a gas discharge lamp, it deviates from the chromaticity point blackbody locus line, only that its closest point chromaticity and 3200K or 5500K, 3200K color temperature was marked or 5500K. To distinguish the difference between the two, the gas discharge light source to the color of the crown "correlated color temperature."

(2) given the same color temperature thermal radiation source and the gas discharge light source does not have the same capacity color. Because fluorescent lamps have significant line spectral distribution characteristics, they are typically lower than the same color temperature color rendering index of thermal radiation source.

Dysprosium lamp (metal halide lamp) relative to the spectral energy distribution graph, showing, among the entire spectrum of a continuous base constituting spectrum of several sandwiched between the spectral emissivity of a strong line spectrum, the blue, the relative proportions of red higher. Dysprosium lamp color temperature between 5000K-600K, its spectral distribution similar to daylight, but the color is less sunlight, the color rendering index between 80-90. It is a high color temperature, high color rendering, high luminous efficiency of a gas discharge lamp, fully satisfactory for the stage, film and television lighting technical requirements of the field, showing more and more broad application prospects.

Xenon light spectrum relative energy distribution curve, the spectral distribution of daylight is very close, the entire spectrum is a continuous spectrum, only a small peak around 480nm, with more radiant energy. It is not difficult to infer: xenon lamp is also a high color temperature of light source, color temperature of about 5500K, with excellent color performance, the color rendering index of up to 94. Xenon excellent overall performance in a gas discharge lamp in outstanding, high luminosity that long-range track lights, projection lamps, spot lights in the development, application results in long flowering.

When the stage lights were slowly dimming dimming, light color and color temperature of the light source will produce a corresponding change, indicating that the relative spectral radiant energy distribution changed. For example, tungsten-halogen light down from the nominal voltage value, variation of optical parameters are: brightness and color temperature decreases, the light color gradually shifted toward the red direction, and vice versa, if the operating voltage push up the brightness and color temperature will increase light color from red to yellow-white folding color gradient, in the case of color film headlight configuration, when using dimming or rated voltage state, to consider the color temperature changes caused by the joint shade change trend.

2, shade and spectral analysis

Light colors may achieve the conversion, the simplest, most practical, the most commonly used method is the light source (or lamps) before configuring a special filter to get your new light color.

There are two types of filters: color temperature conversion filter (also known as Color Correction filter) and colored light filters. The color filter having selective light absorption optical properties, such as color filter medium of the visible spectrum of light having respective wavelengths different proportions of the absorption, the relative change in the spectral energy distribution of the light source, the light transmissivity induced stimulation of human eye Unlike the light source color effect. Color filters of different products have their own different spectral transmittance curve, they convey the optical properties of different selective absorption.