How to Detect the Gloss of the Mirror With a Gloss Meter
Different mirrors have different gloss levels due to their ability to produce specularly reflected light on the surface. This article briefly introduces the mirror gloss measurement method for everyone.
1. What is the gloss of the mirror?
The gloss of a mirror refers to its ability to produce specular reflection on the surface. The brightness of the mirror reflection is determined by the sharpness and flatness of object surface. All bright, highly reflective surfaces are called specular or high gloss.
Gloss, as the surface characteristic of an object, depends on the surface's ability to specularly reflect light. The so-called specular reflection refers to a reflection phenomenon with the same reflection angle and incident angle. Gloss is a physical quantity that evaluates the ability of a material's surface to reflect light under a set of geometrically prescribed conditions.
How to Detect the Gloss of the Mirror With a Gloss Meter
For the gloss measurement, it is a standard relative measurement using highly polished black glass with a refractive index np = 1.567 as a reference. Assuming that the surface is in an ideal polished state, the plane can specularly reflect the speed of natural light and define a gloss value of 100.0 GU at this time. Then when measuring the surface gloss of other objects, it is usually expressed by multiplying the reflectance of the sample in the specular (orthogonal) direction relative to the standard surface by 100, that is, G = 100R / R. Therefore, the gloss of the mirror is generally compared with the standard plate to calculate the gloss value and there is no fixed size.
2. Mirror gloss detection method
For commonly used mirror products, in order to control the production quality, it can be measured with a specular gloss meter . In general, a geometric angle of 60 ° can be used to measure most samples and determine whether the measurement angle is appropriate. The 20 ° geometric angle can be used to measure high-gloss objects. The 85 ° geometric angle is suitable for measuring low-gloss objects.
The gloss value determined by this method can be obtained by comparing the specular reflection of the sample with the standard black specular reflection. Because the specular reflection also depends on the refractive index of the sample surface, the measured gloss nominal value also changes with the surface refractive index. However, in order to obtain a gloss value, the specular reflection of two samples with similar surface refractive indices is usually compared.
The 60-degree angle generally used on the market is like LS192, a universal 60-degree specular gloss meter from Linshang Technology. Glossy materials can be tested because the gloss is a relative value. When there is no uniform standard in the applied industry, it can be tested with the LS192 specular gloss meter. If the industry has a uniform standard, it is best to use the same angle of testing.