International standard light source light boxes are divided into two types: domestic light boxes and imported light source color light boxes. Imported light source light boxes are expensive and have high calibration accuracy. They are mainly used by large enterprises and enterprises with strict color requirements; while domestic standards are suitable for Color light boxes are cheap and suitable for most small businesses.
Standard light source light box usage parameters
Standard light source color matching light boxes are usually a combination of multiple light sources. D65 and D50 are used to help users simulate daylight, TL84, CWF, and U30 are used to simulate store showroom lights, as well as home lights F and INCA. , horizontal daylight HORIZON, ultraviolet lamp UV, etc. The parameters corresponding to each light source are different.
A light source: color temperature is 2845K, equivalent to the light radiated by an incandescent lamp at 2800K .B light source: The correlated color temperature is 4800K, which is equivalent to direct sunlight at noon. C light source: The correlated color temperature is 6700K, which is equivalent to natural light during the day. It has more blue components. D65 light source: The correlated color temperature is 6500K, which is equivalent to the average daytime Illumination, in recent years, is often used as the standard light source for color TVs. E light source: also known as isoenergetic white light, that is, P (l) = constant. It is a hypothetical light source that does not actually exist. Using it is purely To simplify calculations in colorimetry, its correlated color temperature is 550K. The F series of illuminants represents various types of fluorescent lighting.
Different color temperatures, different light colors
Different color temperatures of light sources, different light colors They are also different, and the feelings they bring are also different:
Some people think that there is a preference in color temperature It depends on the person. This is related to the scenery we see every day. For example, people who live close to the equator usually see an average color temperature of 11000K (8000K (dusk) ~ 17000K (noon)), so they prefer high color temperatures. (It looks more realistic). On the contrary, people in areas with higher latitudes (average color temperature is about 6000K) prefer low color temperatures (5600K or 6500K). That is to say, if you use a high color temperature TV to perform Arctic scenery looks bluish; conversely, if you use a TV with a low color temperature to watch subtropical scenery, you will feel a bit reddish.
Colors are usually observed under daylight, so fine color discrimination work in industrial production requires that the lighting source must have a spectral power distribution that approximates real sunlight, which is the D65 standard stipulated by CIE. Light source, D65 standard light source light box is also a color matching light box with large demand in the market.
However, in the color matching process, there is a very special phenomenon: the sample and the sample will appear to be the same color under the first light source, but will appear different under another light source. The difference in color is the so-called metameric phenomenon.
If you formulate mass-produced color products in your own light environment and fail to eliminate the problem of metamerism, when customers have objections under widely varying light environments, Complaints and even returns may occur, and troubles and losses are inevitable.
Therefore, before you determine the color matching or issue a production order, you need to use the “A” light source to test the metamerism effect to ensure that it is foolproof.
Use the color light box to observe the angle
In the textile printing and dyeing industry, color matching light boxes are most commonly used for color matching. Improper use methods lead to deviations in color matching and light for users. How to make the color light observed by different observers under the light box consistent? ?
Then we must use the color matching light box correctly and standardly, and we can start from 9 aspects.
1. Observation angle
The following points are required for standard color matching light boxes Various facilities and the viewing angle will also directly affect the evaluation results. According to international standards, only two observation angles can be used, they are:
Zero-degree light source, 45-degree observation (0°-45°), that is, the light source is from zero degrees (vertical) The incident angle is illuminated on the sample, and the observer observes the sample from 45 degrees.
Light source, 45° inclined table, 45° light source, zero degree observation (0°-45°), in this layout a specific 45° inclined table (45angle table) must be used to make the light source The light shines on the sample from 45 degrees, and the observer observes the sample from zero degrees (vertical).
2. 45° light source detection sample placement
No matter When using any of the above observation methods, it must be noted that the test sample is placed in the middle of the light box as much as possible to reduce the influence of external light sources.
In addition, the most important thing is that when you need to compare the colors of two or more items, you should try not to overlap them for observation. It is best to put them side by side in the order box. Compare with the same.
3. Light box maintenance
A complete maintenance plan can ensure that the light box is in standard condition for a long time: 1. If used Be careful not to contaminate the inner wall of the light box; 2. If stains or peeling paint are found, personnel should be sent immediately to repair or replace the inner wall panels, and the use or brightness of the lamps should be checked frequently.
4. Perform color matchingRequirements for environmental factors
All external light that will have the opportunity to shine on the test sample must be avoided as much as possible. If the window is within the field of vision, gray curtains should also be installed. Mask it, so using a color-matching light box in a dark room is ideal. Another point that is often overlooked is that no other debris should be placed in the color light box.
5. It has the function of testing metameric effects
The so-called The metamerism effect means that under a certain light source, the color displayed by the sample is the same as the requirement, but under another light source, the color difference is unacceptable. Under the D65 light source, there is no difference between the color and the standard, but under the A light source, the color of the sample is unacceptable. Therefore, all equipment that measures color light sources must be equipped with two or more light sources to test the metamerism effect.
6. Requirements when converting light sources
Based on daily life experience, in our eyes, it is like having a Temporary register, when the color changes in a very short time, we can clearly feel it. Therefore, when observing metamerism, if you want to change the light source, it must be done in an instant. It must not be like the lighting tubes we use daily, which have to flash and then turn on, because this will irritate the eyes. department, affecting the review results.
7. Record the time used for standard tube setting
All standard color light sources are also It is produced by lamp tubes or light bulbs, and the manufacturer will also list that the quality of its products remains within acceptable tolerances within a certain period of operation. Therefore an accurate time recorder is indispensable. Usually these tubes need to be replaced if they are used for more than 2000 hours or a year.
8. Ultraviolet light source
Due to the current industrial Fluorescent and whitening dyes are commonly used, and the best way to detect these effects is to use a non-UV light source, never focusing on one area.
9. Arrangement of lamp tubes
Although the arrangement of lamp tubes There are no specific requirements for the arrangement position, but the distribution position must be such that there is a uniform light source in the opposite color light box, and it must not be biased to a certain area.
Other matters: No matter which color detection method is used, it must be noted that the test sample is placed in the middle of the color matching light box as much as possible to reduce the number of other colors in the room. Effect of light source. In addition, the most important thing is that when you need to compare the colors of two or more objects, try not to overlap them for viewing. It is best to place them side by side in a light box for comparison. After testing the sample with the color calibration light box, you need to press the ON/OFF button. If it is not used for a long time, you need to turn off the power switch of the color calibration light box.
Maintenance and repair of color matching light boxes
1. It is strictly forbidden to put debris in the color matching light box to avoid damaging the medium gray color of the inner wall ( Neutral (Gray), causing errors in color matching.
2. Do not start the light tube too frequently, otherwise it will affect the life of the light tube.
3. The distribution of various light sources within the body must be installed according to the “lamp distribution diagram” to obtain uniform and sufficient light sources.
4. It is forbidden to place thermal insulation materials on the top of the light box, so that the heat generated when the electronic ballast is working can be dissipated in time and extend its life.
5. If the power is turned on and the start button does not respond, you should check whether there is electricity in the power supply or check whether the fuse under the power base of the machine is damaged.
6. If the light pipe flashes, please check whether the light pipe is installed in place or check whether the electronic ballast is working stably.
Light box maintenance
Color-matching light boxes require maintenance, especially It is an imported color-matching light box, which can easily cost 50,000 or more than 100,000. Proper daily maintenance can ensure that the color-matching light box remains in standard condition for a long time. For example, be careful when using the light box daily and do not stain the inner wall of the light box; if you find stains or peeling paint , it is best to send personnel to promptly correct or replace the inner wall panels, and often check the usage time or brightness of the lamps in the color light box when you have time. </p