There are 3 main reasons why calibration is important, especially within the manufacturing and testing industries:

1. Accuracy – to ensure that all results are accurate and true
2. Consistency – to ensure that each test is measured against a consistent and repeatable result
3. Standardisation – calibration and servicing ensures that measuring devices remain in conformance to measuring standards, a requirement for most industries

Each glossmeter is setup by the manufacturer to be linear throughout its measuring range by calibrating this to a set of master calibration tiles traceable to NMI. 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 National Standards such as NMI.  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 re-calibration 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 traceable artefact  not the gloss-meter, however it is often recommended by manufacturers that the instrument is also checked to verify its operation on a frequency dependent on the operating conditions.