Method for Judging Gloss of Wood Coating
1. What is the gloss of wood coatings?
Wooden products with different gloss will have certain visual differences when visually observed. The gloss refers to the fact that at a specific angle, the surface has a large amount of regular reflection and the gloss is high, otherwise it is rough. The surface has many diffuse reflections and the gloss is low.
The gloss measurement of wood and paint film is carried out by a glossmeter, which is expressed as a percentage of the intensity of reflected light to the intensity of incident light. The gloss parameter is composed of three indexes, that is, the gloss parallel to the wood grain direction and the gloss perpendicular to the wood grain direction and two indexes of the two gloss ratios. These three indicators can effectively and reasonably reflect the change of gloss characteristics before and after the wood finishing.
2. Effect of wood coating on surface gloss
Generally speaking, the gloss of wood is improved after coating with various varnishes. It increases continuously with the increase of the number of paintings. The variation of various gloss parameters of different woods before and after painting is different. And the varnish parameters of polyurethane varnish, nitro lacquer and alkyd varnish with different coating times are basically the same, that is, they increase continuously with the increase of the number of paintings.
3. Wood coating gloss test
In order to accurately assess the effect of wood coatings on the surface gloss, we can detect it with a professional glossmeter. As the name suggests, the glossmeter measures the gloss of materials. Its basic principle is also very simple and easy to understand. That is, a light source is emitted by a transmitter and the receiver (composed of a lens and a photosensitive element) can receive the reflected light. The glossmeter is classified according to the accuracy of gloss. There are three types of high gloss, medium gloss and low gloss.
Gloss is measured using a glossmeter. Most glossmeters measure the surface reflectance of an object, which is called a specular glossmeter. The measurement results are different depending on the angle of incidence selected during the measurement. The larger the angle of incidence, the greater the specular reflectance and the higher the gloss. That is why high-gloss materials should be measured with a high-gloss measuring instrument at an angle of 20 degrees. Conversely, the lower the specular reflectance, the lower the gloss. Customers can use glossmeter with an 85-degree angle. It can be seen that the level of gloss depends not only on the surface characteristics of the object, but also on the measuring angle of the instrument.
The general angle on the market is a 60-degree angle. Like the general-purpose 60-degree glossmeter LS192 from Linshang Technology, the measurement range reaches 1000GU. High-gloss and low-gloss materials can be tested because gloss is a relative value. When there is no uniform standard in the industry, the LS192 glossmeter can be used for testing. If the industry has a uniform standard, it is best to use the same angle of testing. Therefore, when selecting the measurement angle, you should choose differently according to different situations. The glossmeter LS192 is the best choice for testing the gloss of wood coatings.