Visual appearance can determine a personÃ¢¬¢s perception of a product. Perception is subjective. A key measurement parameter used to define and quantify a productÃ¢¬¢s overall visual quality is gloss.
Gloss is measured by directing a constant intensity light beam, at a fixed angle, on to the test surface and then monitoring the amount of reflected light from the same angle. This specular reflectance is measured using a glossmeter. Different surfaces require different reflective angles.
Surfaces with a brilliant or highly polished
finish reflect images clearly. This distinct reflection is
caused by the incident light reflecting on the surface
in a specular direction.
Semi and matt surfaces reflect images less distinctly and with reduced intensity.
On semi or matt surfaces light not only reflects in a specular direction but also is scattered causing the reflected image to appear diffused.
Choosing the correct angle for gloss measurement:
Gloss measurement is based on the amount of light reflected on the surface relative to a polished glass reference standard, measured in Gloss Units (GU). The amount of light that is reflected on the surface is dependent on the angle of incidence and the properties of the surface.
Gloss is categorized as either matt, semi or high gloss. In order to determine the most appropriate measurement angle start with a glossmeter set at a 60° angle of incidence.
If the result is between 10 - 70GU, the coating is termed Ã¢¬Ësemi-glossÃ¢¬¢ and should be measured using the 60° angle. If the result is less than 10GU, the product is Ã¢¬Ëlow glossÃ¢¬¢ and should be measured using the 85° angle and if it is greater than 70GU, the product is known as Ã¢¬Ëhigh glossÃ¢¬¢ and should be measured using the 20° angle.
All three angles should be recorded (20, 60 & 85°) when measuring gloss on anodized metals to ensure a complete understanding of the specular reflectance between the coating and the metal substrate.
% Reflectance (%)
% Reflectance compares the amount of light energy transmitted and received by a glossmeter and expresses the value as a percentage. The shinier a surface is, the closer the value will be to 100%.
Whilst the Gloss Unit (GU) scale is linear, each angle of incidence has a d measurement range; 0 Ã¢¬ 2000GU (20°), 0 Ã¢¬ 1000GU (60°), 0 Ã¢¬ 160GU (85°).
% Reflectance displays the measurement value as a percentage relative to the selected angle of incidence. For example, a value of 1000GU at 20° would be expressed as 50%20 and 500GU would be expressed as 25%20, but at 60° this would be expressed as 50%60.
Haze causes a drop in reflected contrast and causes Ã¢¬ËhalosÃ¢¬¢ to appear around the reflected light sources, dramatically reducing the visual quality.
In accordance with ASTM D4039 haze is defined as the numeric difference between the specular Reflectance at 60° and 20°.
This is expressed in Haze Units (HU).
Imbotec Elcometer Glossmeters
The Imbotec Elcometer range of glossmeters are easy to use and combine high accuracy, repeatability, and reproducibility with functionality making them the most advanced glossmeters on the market today.
Ã¢¡ Small, robust & ergonomic
Ã¢¡ 3 - 10 readings per second
Ã¢¡ Repeatable, reproducible & accurate
Ã¢¡ 60° angle
Ã¢¡ 40,000 reading memory in up to 2,500 batches
Ã¢¡ Date and time stamped readings
Ã¢¡ USB & Bluetooth® data output
Ã¢¡ PC, iPhone or AndroidTM compatible
Ã¢¡ Automatic gauge & tile diagnostics
Ã¢¡ Auto calibration tile recognition via RFIDÃ¢¬
Small, robust and ergonomic, the Elcometer 480 range of glossmeters have been designed to exceed the demands of the industry today.
Combining easy to use, multi-lingual menu structures with exceptional repeatability, reproducibility & accuracy, the Elcometer 480 provides users with best in class hand-held gloss measurement.
Using state of the art design and manufacturing techniques provides world-leading features and functionality - reliably measuring & recording Gloss, % Reflectance & Haze on any material, including paint, plastic, ceramic or metal.
The Elcometer 480Ã¢¬¢s rapid LED technology accurately measures up to 3 angles at the same time at a rate of 10 readings per second.
Measurements can be instantly transferred to PC, iPhone, AndroidTM or other mobile devices via USB or Bluetooth®.
Using the ElcoMaster® software, professional reports for gloss and other appearance measurements can be quickly generated. Alternatively, gloss readings can be combined with other key measurement parameters such as coating thickness, adhesion and oven temperature pro le - within the same software package.
The Elcometer 480 is available as either a simple entry level 60° glossmeter or state of the art Single, Dual or Triple angle variants.
Dual: 20° & 60°
Triple: 20°, 60° & 85°
Memory and Batching
Store 40,000 date and time stamped readings in up to 2,500 user definable alpha-numeric batches.
Readings can be transferred to PC, iPhone, AndroidTM or other mobile devices via USB or Bluetooth® for instant reporting using ElcoMaster® software.
Fully customizable, scratch and solvent resistant color LCD allow the user to display:
Gloss, % Reflectance or Haze readings
Readings and Differential with pass/fail
Analogue Scan Bar
Standard, Auto Repeat & Scan Modes
No two inspections are the same. It is for this reason that the Elcometer 480 is equipped with three measurement modes:
Standard Mode: Press the measure button to take an individual spot measurement.
Auto Repeat Mode: When the glossmeter is slid over the surface a measurement of all three angles is automatically taken at a user-definable rate between 10 - 180 readings per minute. When enabled all the individual readings are stored in memory.
Scan Mode: As the glossmeter slides over the entire surface area the gauge measures all three angles at a continuous rate of 10 readings per second. When stopped, the gauge displays and stores the average, highest and lowest values - ideal for checking a sampleÃ¢¬¢s overall uniformity.