How to measure gloss using the PosiTector GLS Gloss Meter, from DeFelsko—the measure of quality.
Gloss is an optical property that indicates how well a surface reflects light in a specular, (mirror-like) direction.
It refers to how lustrous or shiny an object appears, generally affecting it’s aesthetic and perceived value.
On high-gloss surfaces, light is reflected at the angle of incidence. On matte surfaces, the light is diffusely scattered in all directions.
Several factors can influence the gloss of a product, including texture, coating properties, and paint application.
By taking gloss measurements, process issues and defective parts can be identified—maximizing consistency, reducing waste, and improving quality.
Gloss is typically measured and reported in Gloss Units or “G.U.” as defined by standards such as ASTM D523 and ISO 2813.
Additionally, some gloss meters, like the PosiTector GLS, are capable of measuring Reflectance and Haze Index.
Reflectance is a measurement of the amount of light detected versus the amount of light sent and is expressed as a percentage.
Haze is the appearance of a “milky” halo or bloom perceived in reflective surfaces due to microscopic imperfections.
The ‘Haze Index’ is measured according to ASTM D4039 by subtracting the 20° from the 60° specular gloss measurements.
Because of the vast range of gloss values, different measurement angles are used to provide the best resolution across matte, semi, and glossy samples.
The 60 degree measurement angle is the recommended starting point, and is used to measure many common finishes such as interior wall paints, furniture, packaging materials, and plastics.
Finishes that read greater than 70 GU at the 60 degree measurement angle are considered high-gloss, and should be measured using a 20 degree measurement angle. These finishes are often seen on cars, traffic signs, and other applications where a reflective or mirror-like finish is desired.
Finishes that read lower than 10 GU at the 60 degree measurement angle are considered matte, and should be measured using the 85 degree measurement angle. Gloss measurements in this range are commonly seen on products such as fabrics, leather, and military assets.
The PosiTector GLS Gloss Meter is the ideal instrument for quality control specialists. Three probe models are available.
The PosiTector GLS 60° is suitable for most gloss applications and is the preferred angle for measuring semi-gloss.
The PosiTector GLS 20°/60° is ideal for high- to semi- gloss applications and has the ability to calculate haze index.
The PosiTector GLS 20°/60°/85° is suitable for all gloss applications—high-, semi-, and matte. It is also capable of calculating haze index.
When powered on, the probe performs an automatic self-check and calibration using the calibration standard incorporated into the protective base plate. A traceable certificate of calibration for both the probe and standard are included.
For some applications, it may be desirable to calibrate the probe to a different calibration standard. Easily add and manage up to 99 different standards.
The durable all-metal probe is designed for long term stability and a long service life. It is connected to the PosiTector gage body via cable, making it ideal for measuring tight or awkward applications.
The PosiTector gage body is also compatible with any PosiTector probe, quickly converting from a gloss meter to a coating thickness gage, surface profile gage, environmental meter, and more.
Two gage bodies are available:
The Standard gage body is compatible with all PosiTector GLS probes, has a HiLo Alarm mode, and can display on-screen statistics such as the average, standard deviation, min/max, and number of readings while measuring, storing up to 1,000 readings.
The Advanced gage body includes all of the functionality of the standard model, plus storage of up to 250,000 readings in up to 1,000 batches and additional functionality such as scanning and differential modes:
By default, the PosiTector GLS is capable of measuring 1 reading per second.
With Normal Scan Mode enabled, it is capable of continuously measuring and saving up to 120 readings per minute.
With Statistics Scan, the probe continuously measures and displays real-time scan statistics, saving only the statistical summary for each scan into memory.
For quick inspection or for pass/fail checks, HiLo mode visibly and audibly alerts the user when measurements exceed user-specified limits.
Differential mode automatically calculates the difference between the current reading and a stored reference value—ideal for comparing results to a known target value.
Taking gloss measurements with the PosiTector GLS Gloss Meter is fast and easy.
Power the gage on with the center navigation button.
The PosiTector GLS will automatically perform a calibration every time the gage is powered on. Be sure that the probe is fitted into the included protective base plate with integrated calibration standard.
Periodically, or when dust or debris is visible, the gloss standard should be cleaned using the included cleaning wipes. Ensuring the standard tile stays clean is critical to ensuring the accuracy of the meter.
The PosiTector GLS is now ready to measure.
Remove the protective base plate from the probe and place the probe on a firm, flat surface.
Simply press the button to take a reading. When a measurement is obtained, the gage beeps twice and the measurement is displayed.
When inspection is complete, download the readings using the built-in USB port or alternatively via WiFi or Bluetooth if using an Advanced gage body.
When connected, download, view, and print stored readings in professional PDF reports quickly and easily with PosiSoft Desktop.
Fully customized reports can be created to match existing paper forms or layouts.
The new PosiTector GLS Gloss Meter is the simple, durable, and accurate way to measure gloss.
With an easy-to-use interface, fast measurement speed, onboard memory, and easy reporting solutions—all backed by DeFelsko’s renowned quality, customer service, and exceptional two-year warranty—the PosiTector GLS Gloss Meter is the ideal choice for gloss measurement.
Visit DeFelsko.com/GLS for a complete list of features.