Paint Gloss Standards and Paint Gloss Meter

1. What is the gloss in paint?

Gloss is an indicator to evaluate the visual impression of the coating surface. It is the result of the physical optical effect between the light and the surface of the article. Light irradiating the substrate surface will produce light reflection. But if the surface is not smooth, the reflected light will not be in one direction otherwise diffuse in all directions. The image quality is low, the impression is no longer bright, but blurred, so the gloss of the coating film is low. The more light that is directly reflected, the more obvious the sense of gloss. The smooth surface can clearly reflect the image. Therefore, the incident light is only reflected in the main reflective direction. The incident angle is equal to the reflection angle. The scattered light is less and the human eye is particularly sensitive to gloss. It is often said that the gloss of a workpiece is 80% or 80 °, which is actually not accurate. The correct expression is that the gloss is 80 or 80 gloss units (GU).
       Paint gloss refers to the coating film paint gloss, which is measured with a paint gloss meter at a certain angle. When the gloss is very high, use 20 ° measurement angle (such as car, motorcycle topcoat), when the gloss is low, use 60 ° 85 ° measurement angle.

2. Standards for dividing paint glossiness

Among them, the gloss of paints refers to paints and varnishes in the international standard classification. In China's standard classification, it involves the basic standards and general methods of paint, the basic standards of pigments and general methods.
       Different types of paints will have different gloss, there are usually three. The gloss of gloss paint is above 70%, which is more of magnetic paint. The gloss of semi-gloss paint is 20% -40%, which mostly belongs to indoor latex paint. The gloss of the matte paint will not be higher than 10% and it is generally more of a primer.
       The gloss of black matt paint can be divided into the following types: ultra-matte, matte, eggshell light (soft light), silk (satin), semi-gloss (semi-matte), high gloss (bright). The gloss is from low to high and the division is based on the degree of reflection of light.
       (1) Among oil-based paints (paints), there are three kinds of matte, semi-matte and high-gloss. The three glosses are not graded, but are used in different places, such as doors and windows and furniture. High gloss is generally used, because the general hardness of high gloss is correspondingly high.
       (2) In water-based paints (latex paints), almost all glosses are available, except that our people have only heard and used matte before. Now that the living conditions are good, the latex paint with gloss is more and more accepted and used by everyone.
       (3) Matte latex paint is lower in cost and easy to brush than glossy ones, but the paint film is easy to powder, scrub resistance and hardness are much lower than the gloss latex paint.

3. Paint gloss meters for testing gloss of paint

The signs of glossiness include specular glossiness, contrast glossiness and vividness glossiness. The paint gloss meter is an glossiness measurement device specially used to measure the gloss of the object surface. It consists of a light source, a detector, a comparison circuit, an analog-to-digital conversion and a digital display. The light source enters a beam of parallel light onto the sample at an incident angle of 60 °. The detector P1 measures the specular reflection (60 °) light and the detector P2 measures the diffusion perpendicular to the specular reflection (ie -30 °) reflected light. After the photoelectric conversion, the electrical signal is sent to the comparison circuit. After comparison, it is sent to analog-to-digital conversion, which converts the glossy analog quantity into a digital quantity and displays it. Linshang paint gloss meter   LS192 is often used to measure the gloss uniformity of the coating surface. The LS192 paint gloss meter use 60 ° angle, large range and measurement range of 0-1000GU, all kinds of high and low gloss coatings can be measured.
       The paint gloss meter LS192 intelligently counts the maximum, minimum, average and standard deviation of paint gloss during measurement. From the difference, the uniformity of paint gloss can be seen.