The assessment of changes to a component by means of an inspection is usually initially carried out purely visually. For this purpose, the surface is compared with the initial condition or a master sample under standardised lighting conditions. Frequently, evaluation tables or a grey scale are taken into account in the assessment. Any conspicuous features such as blistering or paint peeling are also noted in the report.
Alternatively, colour changes during batch changes or due to environmental influences can be quantified by colour and gloss measuring devices. The measuring geometries are standardised in order to obtain comparable values. The gloss measurement determines the directional part of the reflection of a surface. Different standardised measuring geometries (20°, 60° and 90°) are available for the measurement in order to cover the entire measuring range from deep matt to high gloss in accordance with the standard. For colour measurement, either colour values in the CIE Lab colour space or spectral curves are obtained.