The jetness or “blackness” of Pigment Carbon Black can be quantified by the color-independent blackness value as the MY value according to DIN 55979, using a paste of the carbon black pigment with boiled linseed oil.
The paste is applied to a glass plate under precisely defined conditions and the reflection of the green component, responsible for the brightness sensation, is measured. The reflected fraction is converted to the MY value. How the decreasing reflection is taken into account in a super-proportional manner, as is usually the case with a logarithmic scale. In black coatings, pigment carbon blacks show MY values between 200 and 300 and even above.
The color-dependent blackness value MC can be determined with additional colorimetric tests.
The hue of the black coloration can be determined from the difference between MC and MY. Gloss has a major influence on the measurable jetness of a black paint and on the subjective “black perception” of an observer.
As a rule of thumb, the lower the gloss, the lower the jetness.