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| title | chunk | source | category | tags | date_saved | instance |
|---|---|---|---|---|---|---|
| Glossmeter | 2/2 | https://en.wikipedia.org/wiki/Glossmeter | reference | science, encyclopedia | 2026-05-05T09:43:10.484367+00:00 | kb-cron |
For example, if the measurement made at 60° is greater than 70 GU, the measurement angle should be changed to 20° to optimise measurement accuracy. Three types of instruments are available on the market: 60° single angle instruments, a combination of 20° and 60° and one type that combines 20°, 60° and 85°. Two additional angles are used for other materials. An angle of 45° is specified for the measurement of ceramics, films, textiles and anodised aluminium, whilst 75° is specified for paper and printed materials.
== Gloss units == The measurement scale, gloss units (GU), of a glossmeter is a scaling based on a highly polished reference black glass standard with a defined refractive index having a specular reflectance of 100GU at the specified angle. This standard is used to establish an upper point calibration of 100 with the lower end point established at 0 on a perfectly matte surface. This scaling is suitable for most non-metallic coatings and materials (paints and plastics) as they generally fall within this range. For other materials, highly reflective in appearance (mirrors, plated / raw metal components), higher values can be achieved reaching 2000 Gloss Units. For transparent materials, these values can also be increased due to multiple reflections within the material. For these applications it is common to use percent reflection of incident light rather than gloss units
== Standards ==
== Calibration == Each glossmeter is set up by the manufacturer to be linear throughout its measuring range by calibrating to a set of master calibration tiles traceable to a national or international standard like ISO 2813 or Germany's Federal Institute for Materials Research and Testing (BAM). In order to maintain the performance and linearity of the glossmeter it is recommended to use a checking standard tile. This standard tile has assigned gloss unit values for each angle of measurement which are also traceable to a national standard such as German's BAM. The instrument is calibrated to this checking standard which is commonly referred to as a 'calibration tile' or 'calibration standard'. The interval of checking this calibration is dependent on the frequency of use and the operating conditions of the glossmeter. It has been seen that standard calibration tiles kept in optimum conditions can become contaminated and change by a few gloss units over a period of years. Standard tiles which are used in working conditions will require regular calibration or checking by the instrument manufacturer or glossmeter calibration specialist. A period of one year between standard tile recalibration should be regarded as a minimum period. If a calibration standard becomes permanently scratched or damaged at any time it will require immediate recalibration or replacement as the glossmeter may give incorrect readings. International standards state that it is the tile that is the calibrated and a traceable artefact not the glossmeter. However it is often recommended by manufacturers that the instrument also be checked to verify its operation on a frequency dependent on the operating conditions.
== Development ==
The glossmeter is a useful instrument for measuring the gloss of a surface. However, it is not sensitive to other common effects which reduce appearance quality such as haze and orange peel. Haze is caused by microscopic surface structure which slightly changes the direction of a reflected light causing a bloom adjacent to the specular (gloss) angle. The surface has less reflective contrast and a shallow milky effect. Orange peel is caused by an uneven surface formation of large surface structures distorting the reflected light.
Two high gloss surfaces can measure identically with a standard glossmeter but can be visually very different. Instruments are available to quantify orange peel by measuring distinctness of image (DOI) or reflected image quality (RIQ) and haze.
== Applications == The glossmeter is adopted by many industries, from paper mills to automotive and is used at each stage of the manufacturing process from goods receipt through to final inspection. Examples include: paints; powder and wood coatings; additives; inks; plastics; automative, glass, and yacht manufacturing; aerospace, polished stone and metal; consumer electronics; and anodised metals.
== See also == Drawdown card – Tool for assessing opacity and contrast ratio of coatings Paint sheen – Glossiness of a paint finish Visual appearance – How matter appears by virtue of interaction with light
== References ==
== External links == PCI Magazin article: What is the Level of Confidence in Measuring Gloss? Gloss Meter 60° - Caltech India Tri Angle Gloss Meter (20°/60°/85°) - Caltech India