What is the paper gloss? Gloss is a characteristic of the object surface. We often say that the gloss refers to the ability of the object surface to reflect light specularly. It is mainly due to the flatness of the paper surface. If the paper has high gloss, it will make the print appear bright. However, when the paper gloss is too high, it will produce a strong reflection, which easily causes eye fatigue and is not suitable for reading. For example, for the coated paper, color printing, packaging, outdoor poster advertising, etc. We must use high-gloss printing paper, while the gloss of traditional paper books should not be too high in order to improve the reading experience.
The definition of professional point is: paper gloss is the paper surface's ability to reflect incident light and its full specular reflection ability. Paper gloss is measured using a professional gloss tester. It is difficult to judge the paper gloss with the naked eye.
There are many factors that affect the paper gloss, but the key factor is the smoothness of the paper surface. If the paper surface is uneven and there are various impurities, when a beam of light is irradiated on the paper, it will reflect (diffuse reflection) in all directions and angles. And it will show a low gloss. If the paper surface is smooth and delicate, the diffusion ratio of reflected light will be smaller. When a beam of light is irradiated in the same direction, the proportion of specularly reflected light will be more.
Secondly, for printing paper, the paper gloss has a direct relationship with the inking rate. The same ink film thickness is printed on the paper with different gloss. The paper with high gloss will get higher printing density and gloss. The color of the screen will look brighter and fuller. For papers with poor smoothness, if the ink film thickness is not uniform, the ink transferability during printing will be worse, resulting in different shades of ink color and making the screen colors look dull and messy. In addition to the characteristics of paper gloss itself, gloss is also affected by the physiological and psychological state of the observer.
Although the coating can improve the gloss, the amplitude is not too large, because the paper smoothness has been greatly improved, but the fine unevenness on the surface is completely optically smooth. There is still a considerable amount of light diffused and reflected. To greatly improve the paper gloss surface, calendering the paper is a good measure. The calendering process of the paper in the production process can be a gloss-coated transparent coating that has a more dense, smooth, high-gloss brightness effect. Varnishing is another kind of gloss treatment technology on the printed matter surface. It is coated with a layer of colorless transparent varnish on the printed matter surface. After leveling, drying and calendering, a thin and uniform transparent bright layer is formed on the printed surface. It can also protect the printed matter. The printed matter has the functions of moisture resistance, water resistance, folding resistance, abrasion resistance, antifouling, etc., thereby extending the service life of the printed matter.
Different instruments and different measurement angles will lead to deviations in the gloss of the measured paper. Therefore, if you want to express the paper gloss, you need to choose a precise gloss tester and explain the gloss value. You need to specify the gloss tester used for testing. So how should we use the gloss tester to detect the paper gloss?
It is highly recommended to use Linshang LS192 gloss tester. The specific detection method is as follows:
(1) Remove the lens paper from the standard version and turn it on. 10 seconds self-test time, "OK" is displayed normally.
(2) Remove the base and place the instrument on the gloss tester. The instrument will display the measured value. Short press the power button to save the current value and return to 1 when the number of measurements reaches the maximum number of counts. The maximum, minimum, average and standard deviation values are re-stated. Each time you press the button, the instrument automatically counts the maximum, minimum, average and standard deviation values.
So it is very important to use a good gloss tester to measure the paper gloss. Because a good gloss tester can not only accurately measure the paper gloss, the manufacturer also provide good after-sales service.