Measuring Black--but How?

Published data, often suggesting very high color depth values or blue undertones, are of little use if they do not reflect the optical perception and can only be achieved through the selection of a certain measurement geometry. [...]this study uses three typical measurement instruments (two tabletop devices with different measurement geometries, and one handheld device) that are often used in the industry: * Instrument A: When it is open (gloss excluded), the measured values are close to the impression of the human eye. [...]the present experiments were performed excluding the effect of gloss on the measurement (gloss trap open). Each instrument uses its own calibration standards, which can also lead to inconsistent results. Because the state of zero reflection is defined using the black standard, the design and cleanliness of the standard is of crucial importance. For Samples 5 and 6, on the other hand, there is already significant scatter in the values obtained in the repeatability measurements - in other words, when measuring exactly the same spot in three series of five measurements without moving the plate. [...]it cannot be assumed that this geometry yields reliable results.