How Does a Gloss Meter Work? Understanding Surface Gloss Measurement

I.  What does gloss mean?

When light shines on an object, it can be reflected, refracted, or absorbed to varying degrees. Gloss refers to a surface's ability to reflect light without significant scattering, while glossiness describes the intensity of this effect. Gloss is a visual perception influenced by the brightness of directly reflected light. The way gloss is perceived depends on factors such as surface texture, finish, and viewing conditions. Highly reflective surfaces are classified as glossy, while those with lower reflectance are considered semi-gloss or matte.

The reflectance values of low-gloss matte surfaces are often too subtle to distinguish visually. However, as reflectance increases toward higher gloss levels, the impact of surface texture becomes more pronounced. For this reason, using a gloss meter is essential for accurately measuring a material's gloss and ensuring precise evaluation.

● High gloss surface

A high-gloss surface is one that reflects light in a highly specular manner, meaning the incident light is reflected at the same angle with minimal scattering. This occurs because the surface is smooth and polished, reducing microscopic irregularities that would otherwise diffuse the reflected light. As a result, high-gloss surfaces exhibit sharp, mirror-like reflections and appear brighter due to their ability to efficiently direct light toward the observer.

● Low gloss surface

A low-gloss surface is one that primarily reflects light through diffuse reflection, meaning the incident light is scattered in multiple directions rather than being reflected at a single angle. This occurs due to the roughness and irregularities on the surface at a microscopic level, which disrupt the uniform reflection of light. As a result, low-gloss surfaces appear dull or matte, lacking the sharp reflections seen in high-gloss surfaces.

II. What is a gloss meter?

A gloss meter (glossmeter) is an glossiness measurement equipment which is used to measure the specular reflection (gloss) on the object surface. This device provides quantifiable glossiness measurements, by directing a beam of light at a specific angle and intensity onto a surface, then measuring the amount of light reflected at the same angle on the opposite side, expressing in gloss units(GU). Gloss testers can measure the gloss of materials such as paint, automotive, marble, printing paper, plastics, ceramic, stone, bamboo, leather and many other materials.

● Gloss Unit

The Gloss Unit (GU) is defined in international standards including ISO 2813 and ASTM D523. It is determined by the amount of reflected light from a glass standard of known refractive index.

● Applications

Gloss meters are widely used across various industries to ensure surface quality and consistency. In the automotive industry, they are essential for evaluating car painting, waxing, and coating. In building maintenance, they help assess cleaning effectiveness on surfaces, including solar panels and construction materials. They are also used for appearance inspections of furniture, polished stone, and printed materials. In manufacturing, gloss meters play a key role in quality control for paint, ink, plastic moldings, and polished metal surfaces such as chrome plating. Additionally, they are valuable for evaluating the effectiveness of detergents and washing processes.

III. Why measure gloss with a gloss meter?

Gloss measurement is essential across various industries to ensure product quality, consistency, and aesthetic appeal. A gloss meter provides objective, quantifiable data on surface gloss levels, eliminating subjective visual assessments. Here’s why measuring gloss is important:

1. Quality Control and Consistency

Gloss affects the visual perception of a product. Industries such as automotive, coatings, plastics, and printing require consistent gloss levels to maintain uniformity across production batches. A gloss meter ensures that each product meets the required standards.

2. Aesthetic and Brand Image

Products with the right gloss level convey premium quality and enhance customer appeal. In industries like furniture, cosmetics, and packaging, maintaining a consistent gloss finish strengthens brand identity and consumer trust.

3. Compliance with Industry Standards

Many industries follow specific gloss measurement standards, such as ISO 2813, ASTM D523, and DIN 67530, to ensure products meet regulatory and customer expectations. A gloss meter allows manufacturers to comply with these standards effectively.

4. Performance and Durability Assessment

Gloss measurement is crucial for evaluating coatings, paints, and surface treatments over time. Changes in gloss levels can indicate wear, weathering, or material degradation, helping manufacturers improve durability and performance.

5. Process Optimization and Cost Efficiency

By regularly measuring gloss, manufacturers can detect issues like inconsistent application of coatings, polishing defects, or surface contamination early in the production process. This minimizes rework, reduces material waste, and enhances cost efficiency.

Linshang gloss testers offer high accuracy, stable performance, and compliance with international gloss measurement standards (ISO 2813, ASTM D523, DIN 67530). With user-friendly operation, fast measurement speed, and advanced features such as auto-calibration, Linshang glossmeters provide reliable and repeatable results. Their portable and durable design makes them ideal for various industries, ensuring precise gloss measurement for quality control and process optimization.

IV. How to use a gloss meter?

Many people is concerned about how to operate a gloss meter. Simple operation would benefit lots of users. The method of using different gloss meters will be different. If the instrument has too many buttons and requires cumbersome settings, it is relatively complicated for non-professionals to use. Using Linshang 60° gloss meter of portable size, we can complete the specular reflection gloss measurement with single hand.

V. How does the gloss meter work?

The gloss meter contains a light source, a screen, a receiver as well as a display screen. The measurement principle is shown in the figure below. 

Principle of the gloss meter

The gloss meter usually has various test angles. This angle refers to the occurrence light and the line perpendicular to the plane. Typical geometric angles of 20 degree, 60 degree and also 85 degree. Under the specified light source and geometric angle, a beam of light is irradiated onto the measured object surface. Then the ratio of the luminous flux reflected back from the object surface to the light flux reflected by the standard board multiplied by 100 is the measured object gloss. (The standard board adopt the perfect polished black glass with a refractive index of 1.567 and a gloss of 100)

VI. Tips about choosing gloss meter

1. Gloss meter measurement accuracy

There are three grades of gloss meters: standard gloss meter, first-grade working gloss meter and second-grade working gloss meter. The high-precision gloss tester can meet the standards of first-class working gloss meter. And the reproducibility of the instrument (for multiple tests under the same test conditions of one instrument, the data is stable) and the repeatability (for multiple tests of the same batch of instruments under the same test conditions, the data is consistent) are very good. Linshang gloss meter meets the Chinese national standard of first-class working gloss meters.

2. Gloss meter functions

Gloss meters of different brands are different. The function can be selected according to your actual need.Several functions are important in selecting gloss meter, we will list these functions in the following part:

2.1 High precision

Gloss tester precision plays a significant role in gloss measurement. High precision means that measure the same test material, the measured data will not exceed the accuracy of the gloss meter. (Different gloss meters have different measurement accuracy).

2.2 For quality controle

The gloss meter support switch between normal mode and QC mode, applicable to different scenes. Normal mode: quick reading after put and test; QC mode: realize quick check on incoming material by setting upper and lower limit value and judge "Pass" or not.

2.3 Power-on self-inspection

Not all the gloss detectors have this function. Linshang gloss meter with the power-on self-inspection function can automatically judge whether the standard board is contaminated and give a prompt to avoid inaccurate measurement caused by the standard board contamination affecting the standard value.

2.4 Other functions

Besides these functions, other functions are also quite useful. Linshang gloss checker has small size and is easy to carry. The Linshang glossmeter also provides free PC software and has stable data.

V. 60 degree gloss meter analysis

As shown in the figure above, the specular reflection ability of low-gloss materials is weak.

If a 20-degree angle gloss meter is used for measurement, the light flux received by the detector is very weak after being reflected by the material surface. The data is small comparing with the light reflected by black glass. When measuring low-gloss materials with different gloss levels, the measured value changes a little. The resolution is not accurate enough to distinguish the subtle glossiness differences.

Similarly, if the 85 degree gloss meter is used to measure high gloss materials, the resolution is not accurate enough to distinguish the glossiness differenc too. Therefore, it is recommended to choose 85 degree gloss meter for low gloss materials and 20 degree gloss meter for high gloss materials. If you need to measure the materials with medium gloss, you can choose 60 ° gloss meter and 60 degree angle gloss meter performs better when measuring the surface of high gloss and low gloss materials.

It can be seen from the curves of the three different angle gloss meters measuring different gloss materials: 60-degree angle glossmeters are better than 85-degree glossmeters when measuring high-gloss materials and better than 20-degree gloss when measuring low-gloss materials.

Most 60 degree gloss meters have a test range of 200GU, so 60 degree gloss meters are suitable for testing the surface gloss of most materials. Take the Linshang gloss meter as an example, with a universal angle of 60 °, a gloss measurement range of 200GU and1000GU and a resolution of 0.1GU. In this way, no matter the high gloss or low gloss material can be tested, there is enough resolution to distinguish the difference in gloss of different materials. There is also a large enough range to meet the test requirements of high gloss materials.

Linshang gloss meter is very popular in the market because of its ultra-high precision and good repeatability and reproducibility. If you want to know more about how to choose a suitable gloss meter, please refer to: "How to Measure Gloss with A Gloss Meter? ".

VIII. FAQs about glossmeter

Here are some frequently asked questions (FAQs) about glossmeters to help you better understand these devices.

1.  How to calibrate a gloss meter?

Linshang glossmeter base is a calibration standard plate, just short press the button upon power on and the calibration is complete.

2.  What factors affect gloss measurement accuracy?

● Surface cleanliness: Dirt, dust, or fingerprints can affect readings.

● Measurement angle: Different angles give different gloss values.

● Lighting conditions: External light sources may interfere with measurements.

● Calibration: Using a contaminated or damaged calibration plate can cause errors.

3.  Can a gloss meter measure textured or uneven surfaces?

Gloss meters work best on smooth and uniform surfaces. Textured surfaces may cause variations in reflection, leading to inconsistent readings. For such materials, multiple measurements at different locations are recommended.

4.  Can the gloss meter measure curved surface materials?

Yes, of course. It is recommended to use Linshang LS193 small aperture gloss meter, which has a measuring aperture of only 3*6mm and a measuring range of 1000GU. It can measure small materials, special-shaped materials, and high-gloss objects.

5.  Can the gloss meter measure more transparent materials?

If you want to measure the gloss of a transparent material, you need to put a piece of pure black velvet cloth under the material.