A gray scale is used to assess the change in colors .
In addition to direct color changes, other factors that influence the visual color perception of the human eye , for example smoothness or roughness and gloss of surfaces, can also be checked. Internationally standardized gray scales are used to evaluate the color change of a test object .
Structure of gray scales and the examination process
Gray scales consist of a series of pairs of matt gray platelets, each of which is assigned a level of contrast . The test is carried out by comparing the contrast between the treated and the untreated test specimen with the corresponding grades of the gray scale. It is important that the test is carried out under standard light so that the reproducibility of the test and its result is guaranteed. Handling and use are described in various DIN standards depending on the industry and application .
field of use
Gray scales are always used when colors or color changes are to be assessed, especially in the area of color development and coloring as well as the requalification of surfaces with regard to their color specification in an industrial environment. Examples include applications in the automotive industry , paint industry , aviation industry , carpet industry and in the textile industry .
Advantages and disadvantages of testing with a gray scale
The advantage of checking using the gray scale is that it can be carried out relatively cheaply and quickly. It is also positive that it does not provide a pure OK / NOK result, but a characteristic value which can be interpreted accordingly (e.g. clearly within the tolerance, marginally within or outside of the tolerance, clearly outside the tolerance).
However, the test should only be carried out by trained personnel with appropriate eyesight and under suitable framework conditions. Otherwise there is a risk that the test will give incorrect results. The gray scales must be subjected to proper test equipment management in the sense of a functional quality management , which ensures the suitability and functionality of the test equipment.