Colorimetry and brightness measurement

Colorimetry and brightness measurement

During the colorimetry, we perform the comparison of colour differences (even not visible by the human eye) using a spectrophotometer. We perform the measurements using a Color-Guide Gloss equipment manufactured by Byk-Gardner, which is suitable for both colorimetry and brightness measurement.

During colorimetry, the instrument we use issues a light current from the horizontal symmetry axis of the measuring sphere, which is processed by the sensor placed at 8° from the vertical symmetry axis of the measuring sphere. With this measuring principle, we eliminate any measurement errors arising from the surface structure of the coatings.

We primarily perform our measurements using the CIE-Lab system, which is a measurement process internationally applied and developed for the comparison of different colours. During the colour comparison, the data derived from the spectrum diagrams are compared mathematically.

Different colours can be characterized with spatial vectors starting from the origin of the spatial geometry system. The saturation of the basic colours and at the same time the direction of the vectors are determined by the values of the L, a, b components. The differences between the colours (ÄE) are given by the square roots of the sum-of-squares of the differences of the L, a, b values.

(∆E) = √ (∆L)2 +(∆a)2+(∆b)2  

We continuously register the tests performed using the measuring instruments and record them in logs when ordered. Our logs are suitable for the comparison of the differences in colour (ÄE) and in the individual colour components (ÄL, Äa, Äb) and for representing brightness differences.

Recommended application:

During colorimetry, we perform colour comparison or colour determination using a spectrophotometer. Our clients need colour determination when developing unique custom colours, where colour ideas can be recorded using numbers determined in an accurate manner. The raison d'ętre of colour comparison is for coatings specified by clients that are geographically distant. In this case, the maker of the coating can develop one with a colour identical with the client's requirements, where there is no need of placing the sample plates next to one another.

The measurement results checked and logged in this manner satisfy both parties. It is practical to perform colour comparison tests when a powder lacquer used in continuous production is substituted by a new product, where the colour identity of the workpieces manufactured is a precondition. In those cases where various elements of complex equipment are manufactured in different dusting plant or site, it is necessary to compare the colours of the elements manufactured in order to eliminate any colour difference arising from the different equipment. The parts to be tested can be workpieces and sample plates alike, the composition and degree of treatment of which are optional.

We perform measurements typically within 1 business day on our site, or within 5 business days on the clients' sites, depending on the availability of the measuring instrument.