Difference between 60° and 20° of Gloss Meter
Gloss meter is an instrument used to measure the gloss on the surface of paint, paper, plastic, furniture, ceramics, enamel, marble, rubber, ink, leather, diamond and various fabric products. Gloss meters with different measurement angles are suitable for different items. Gloss can be divided into 3 general ranges, including low gloss, semi gloss and high gloss.
Gloss is a property of an object's appearance. It describes the spatial geometric distribution of light reflected from the surface of a material. There are various methods for measuring the gloss of the sample surface, and mirror reflection is mostly used internationally. This method is to irradiate the standard plate and the sample to be tested at a certain light speed under a certain illumination condition under a specified incident angle, and measure the reflected light of the sample and the standard plate at the specular reflection angle according to the specified acceptance conditions.
The key to gloss measurement is to specify the measurement conditions. Due to different material properties and gloss levels, it is necessary to select different incident conditions and acceptance conditions for mirror angles and light speed. It can be seen from the gloss measurement standard that when testing the gloss of different materials, different measurement angles should be selected. In general, low-gloss samples are measured at large angles, and high-gloss samples are measured at small angles.
For general materials, a 60 degree general-purpose gloss meter is generally selected.
For high-gloss materials, a 20 degree gloss meter is generally selected.
When we use the gloss meter, we often do not know how to choose the gloss measurement angle. All light sources reflect off a surface, and the level of the amount of reflected light is called the surface gloss value. Gloss values are measured in gloss units (GU), corresponding to a standard value of approximately 100 GU.
All angles are calculated from vertical angles. Each range is measured at its own angle. To know which angle to measure at, it's a good idea to start at 60°. If the result is between 10-70GU, the coating is called semi-gloss, measured with 60° measurement angle is good. If the result is above 70GU, the product is high gloss, measured at 20°.