{"id":4708,"date":"2020-07-03T10:30:17","date_gmt":"2020-07-03T10:30:17","guid":{"rendered":"https:\/\/www.samatools.it\/events\/misura-della-brillantezza-con-il-glossmetro\/"},"modified":"2025-05-06T16:47:08","modified_gmt":"2025-05-06T14:47:08","slug":"gloss-measurement-with-glossmeter","status":"publish","type":"post","link":"https:\/\/www.samatools.it\/en\/curiosity\/gloss-measurement-with-glossmeter\/","title":{"rendered":"Gloss vs Brightness: What’s the difference?"},"content":{"rendered":"\n

The difference between gloss and brightness is that gloss is (uncountable) a surface shine or luster\/lustre, while brightness is the quality of being bright.<\/p>\n\n

The glossmeter\u00a0<\/a><\/strong>performs measurement on flat surfaces and operate like a\u00a0refractometer<\/strong>. Gloss and brightness of a particular surface is measured in\u00a0\u201cGloss\u201d<\/strong>\u00a0and it is an optical property, based on the relationship between light and the physical characteristics of the surface, which means the surface capacity to reflect light in a specular way.<\/p>\n\n

Gloss importance<\/h2>\n\n

Brightness is one of the most important parameters of a surface, because it can alter the perception of profiles and shapes, influencing the visual experience.<\/p>\n\n

Brightness acts on the surfaces according to different aspects: angle of incidence of light, observer position, physical properties of surface and observation conditions.<\/p>\n\n

This parameter plays a key role in several production sectors where metrological instruments are relevant in order to standardise the quality control. Brightness measurement was consolidated according to international methods approved by ASTM, DIN e ISO.<\/p>\n\n

Basic physical principle for gloss measurement<\/h2>\n\n

When a light source radiates a surface undergoes a double effect: partly dispersed, partly reflected with opposite angle but with equal amplitude, with respect to the initial radiation.<\/p>\n\n

The brightness of a surface is calculated according to this specular reflection.<\/p>\n\n

This last element determines the gloss level of a surface.<\/p>\n\n

Specular reflection intensity is determined by the material and angle of incidence of the illuminating measured according to certain conditions.<\/p>\n\n

Measurement scale<\/h2>\n\n

Values are conventionally expressed in units of gloss (GU : gloss units) and they refer to a scale based on the index of refraction of a black glass mirror with a reflection 100GU in relation to a specific angle.<\/p>\n\n

All non-metallic materials, such as paints or plastics, can have a value associated to this data, while for highly reflective metal surfaces, such as laminates and other crude materials, the user can measure get up to 2000GU.<\/p>\n\n

Geometry Types \u2013 When and Which one to Choose?<\/h2>\n\n

Gloss meters are divided into two types, mono-angle (60\u00b0) and\u00a0tri \u2013 angle<\/a><\/strong>\u00a0(20\u00b0\/60\u00b0\/85\u00b0).<\/p>\n\n

To have more angular references of the illuminant allows improving measurement accuracy according to the level of brightness of the surface.<\/p>\n\n

\"Gloss<\/figure>
\n

Measurements at\u00a020\u00b0<\/strong>\u00a0are more indicated for\u00a0very bright surfaces<\/strong>;<\/p>\n\n\n\n

Measurements at\u00a060\u00b0<\/strong>\u00a0are more indicated for\u00a0medium bright surfaces<\/strong>;<\/p>\n\n\n\n

Measurements at\u00a085\u00b0<\/strong>\u00a0allow to obtain optimized values for\u00a0little bright surfaces<\/strong>.<\/p>\n<\/div><\/div>\n\n

60\u00b0 geometry is widely used thanks to its range of median use, however it is recommended to refer to 20\u00b0 value for measurements above the 70GU, while 85\u00b0 is preferred for measurements under 10GU.<\/p>\n\n

Example: Measurement of the specular brightness of a painting film<\/h2>\n\n

The moment we are going to paint a wall, we need to decide even about the finish: matt, satin or glossy?<\/p>\n\n

Colour can change according to the brightness grade.<\/p>\n\n

EN ISO 2813 provides for the use of the gloss meter to measure the mirror brightness of a painting film.<\/p>\n\n

Caparol Media, the web portal for colour, decoration, isolation and restoration, shows us in 5 steps how to make measurements.<\/p>\n\n

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  1. Prepare the sample to be measured by applying a paint film and let it dry at 23\u00b0C and with 50 % UR;<\/li>\n\n\n\n
  2. Wait 16 hours for conditioning at constant temperature and RH rate;<\/li>\n\n\n\n
  3. Calibrate the gloss meter<\/li>\n\n\n\n
  4. Repeat the measurement six times in different positions, in a parallel and perpendicular direction to the drafting of the film;<\/li>\n\n\n\n
  5. Calculate the average of measured values and identify the reference ranges.<\/li>\n<\/ol>\n\n

    Upon request, we can carry out calibration reports<\/strong>\u00a0RDT<\/span> <\/a> on the entire instrument or one or all angles (20-60-85\u00b0).<\/p>\n\n

    What are the 5 strengths of the SAMA Tools\u00ae 3-angle digital gloss meter?<\/h2>\n\n
      \n
    • Attractive design<\/li>\n\n\n\n
    • Compact size<\/li>\n\n\n\n
    • Three-angle geometry of the lamp<\/li>\n\n\n\n
    • High-precision<\/li>\n\n\n\n
    • Ideal for quality control on production line or in the field<\/li>\n<\/ul>\n\n
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