Why is the observer degree when rating colors?

As we all know, color light boxes can accurately calibrate the color deviation of goods under the same standard light source for sample production, quality inspection, and acceptance. They can be used for visual evaluation of dyeing fastness, color matching and sampling, identification of color differences and fluorescent substances in industries such as textiles and printing and dyeing, ensuring that the color quality of goods meets the requirements, thereby improving product quality and market competitiveness.

Color matching light boxes are usually a combination of multiple light sources, such as providing simulated daylight D65, D75, D50, simulated store showroom lighting TL84, CWF, U30, as well as home lighting F, INCA, horizontal daylight HORIZON, UV tubes, etc.

These light sources must be approved by international large institutions, such as Wal Mart and Martha's approved store lights, daylight approved by international inspection institutions, and lights with special requirements specified by customers.

We encountered many problems when using standard light source boxes, some of which caused the color of the light boxes to not meet the standards due to some details, causing adverse effects on subsequent production.

Here are 7 key steps to using a standard light source box. If you encounter similar problems, you can refer to them.

1、 Standard usage:

Key step one: Viewing angle

According to international standards, only two viewing angles can be used, which are:

a. Zero degree light source, viewed at 45 degrees (0 ° -45 °), refers to the light source shining on the sample from a zero degree (vertical) incidence angle, and the viewer viewing the sample from 45 degrees.

b. Light source, 45 ° tilt table. 45 degree light source, zero degree viewing (0 ° -45 °), in this layout, a specific 45 degree fixed angle table must be used to illuminate the sample from 45 degrees, allowing the viewer to view the sample from zero degrees (vertical).

Key Step 2: 45 ° Light Source Detection Sample Placement

Regardless of using any of the above viewing methods, caution must be taken that the test sample may be placed in the middle of the lightbox to reduce the impact of external light sources. Other than that, it is important not to overlap the colors of two or more objects when comparing them. Instead, they should be placed side by side for comparison.

Key step three: Environmental factors during color matching

All external light that will have the opportunity to shine on the test sample must be completely avoided. If the window is within the field of view, gray curtains should also be installed to block it, so using a color matching light box in a black room is ideal.

Another thing that is often overlooked is that the color light box must not be filled with other debris.

Key step four: Requirements for converting light sources

Based on daily life experience, in our eyes, it is like having a register, and when the color changes in a very short period of time, we can clearly feel it.

Therefore, when watching the same color spectrum, if you want to change the light source, you must achieve it in an instant. You must not flash like the lighting tubes we use in daily life, as it will stimulate the eyes and affect the evaluation results.

Key Step 5: Possess the function of testing homochromatic heterochromatic effects

The so-called homochromatic heterochromatic effect refers to the phenomenon where a sample displays the same color and requirements under one light source, but its color difference cannot be accepted under another light source. Under the D65 light source, there is no difference in color compared to the standard, but under the A-light source, the sample color cannot be accepted. Therefore, all devices for color matching light sources must be equipped with two or more light sources to test for homochromatic aberration effects.

Key Step 6: List the positions of the lamp tubes

Although there are no specific requirements for the placement of the lamp tubes, their distribution must be in a uniform light source within the color matching light box, and must not deviate from a certain area.

Key step seven: Record the time used for standard management

All standard colorimetric light sources are also produced by lamps or cannons, and manufacturers will also indicate that their products remain within acceptable tolerances for a certain period of operation. Therefore, an accurate time recorder is indispensable. Usually, if these pipes are used for more than 2000 hours or a year, they need to be replaced.

2、 Daily maintenance:

1. The selection of various light sources in the color light box is achieved through the touch buttons corresponding to the light source name on the box, which can quickly switch and light up. The two items that need to compare color deviations are placed in the center symmetrical position of the color light box. As long as the angle between the human eye or light and the tested item is 45 degrees, it is the best observation angle.

2. When using a lightbox, it is important to avoid external light shining on the object being tested, and no other debris should be placed inside the lightbox.

3. After using the color light box tube for more than 2000 hours, it is necessary to replace it with a new one to avoid the impact of aging on the visual observation of color.

4. If there are stains on the inner wall of the lightbox, a clean soft cloth dipped in alkaline low concentration cleaner can be used to wipe it clean, making the inner frame clean, dry, and avoiding damage to the light absorbing PU coating on the inner wall of the lightbox, which will affect the color matching effect.

5. If the inner panel of the lightbox is damaged and cannot absorb light, it should be replaced. If the use of the lamp tube exceeds the time limit and causes blackening and aging at both ends, a new lamp tube should be replaced.