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Standard requirements for light sources in color light boxes
Standard light sources are currently used in many industries for color light boxes. The main function of standard light sources on color light boxes is the color matching and calibration of the appearance of the product. Many products have high requirements for appearance and color, and some even directly affect it. Due to the market sales of the product, manufacturers must strictly control the appearance and color of the product. The role of the standard light source on the color light box is naturally highlighted. Since the standard light source is affected by many conditions on the light source of the color light box, the light color exists. Therefore, the international statistical standards have made a series of requirements for the standard light source for the light source of the color light box. This article will focus on the requirements for marking the light source in the hue phase. 1. Spectral requirements of the light source According to the requirements of ISO3664:2000, ordinary fluorescent tubes can never be used as the light source for observing colors. Special fluorescent tubes must be used that meet the following technical requirements at the same time: (1) The color temperature of the light source must be 5000K or 6500K, that is, observing the color under the color temperature of this light source is basically similar to the effect of observing the color under natural light from 8 am to 10 am and 3 pm to 5 pm in most parts of China. (2) The color rendering index of the light source Ra>90, that is, under this kind of light source, more than 90% of the colors can be correctly observed. 2. The brightness of the light source requires a certain degree of illuminance to observe the color of the object. It can be imagined that nothing can be seen in a dark room. According to the requirements of ISO3664:2000: (1) The brightness of the light source illuminated on the surface of the observed object through reflection should reach 2000Lux (+/-500Lux). The illuminated surface is within the range of 1mX1m, and the brightness of any point shall not be less than 75% of the brightness of the center of the illuminated surface (2) The brightness of the light source irradiated on the surface of the observed object through transmission should reach 1270cd/m2 (+/-320cd/ m2) (3) The brightness of the display should reach >75cd/m2 3. The softness of the light source requires only a few standard light sources. It is impossible to collect the light source and illuminate it evenly and softly on the surface of the illuminated object. . This means that the standard observation light source must have a scientifically designed surrounding light system to ensure that the energy of the light emitted by the fluorescent tube is irradiated on the surface of the illuminated object as much as possible, and there is no light glare or light. Shadows. 4. Requirements of the surrounding environment of the light source Observing colors not only requires a standard light source and suitable light source brightness, but also requires strict requirements on the environment around the light source: (1) Other lighting sources around the observation light source cannot directly or indirectly affect the Observe the surface of the object. (2) Observe the wall panels around the light source. Other colors cannot be used on the top and bottom (including the observer's clothes), and only neutral gray with reflectivity <60% can be used. (3) When observing color transmission photos, there must be a frame with a width of 50mm or more around the photo, and the color of the frame must be black with a blackness of >90%. 5. Color rendering index (Ra) The color rendering index is used to measure the ratio between the color that can be seen under natural light and the color that can be seen under a certain light source, that is, Rau003din a certain light source The color that can be seen under illumination ÷ the color that can be seen under the illumination of natural light. Ra represents the color rendering index of a light source. The closer the Ra is to 100%, the smaller the difference between the color displayed under the light source and the color displayed under natural light. Note: Color temperature and color rendering index are two different physical concepts. The color temperature only reflects the color of the artificial light source, which is warmer or cooler. The color rendering index reflects the type of color that can be displayed under a certain light source. A high color temperature does not mean a high color rendering index, and a high color rendering index does not mean a high color temperature. 6. Color temperature (K) The color temperature of a light source is defined by the burning temperature when the color of the light source is consistent with the color of an absolute black body when it is burned at a high temperature. Its unit is absolute temperature Kelvin (K) . The higher the K value, the more white-blue color appears; the lower the K value, the more yellow-red color appears. 5000K (D50) is a standard light source lamp with a slightly warmer (yellowish) luminous color, which is widely used in advertising art and pre-press fields. But according to ISO3664:2000, this kind of light source is now mandatory for printing and other color management processes. 6500K (D65) is a standard light source lamp with a slightly cooler (blueish) luminous color. Previously in European and American countries, this light source was used in the printing field. However, according to ISO3664:2000, this light source is gradually being replaced by the D50 light source. But in China, the D65 light source is still the standard light source lamp commonly used in the printing field. More about standard color matching light box: http://www.dsdengxiang.com/
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