INSTRUMENTATION | COLOUR MEASUREMENT
that stripping or shaking leads to better results, simple filling provides the most stable result. “The easy filling of a sample tray with pellets, which can be handled quickly and safely during the production process leads — by averaging over a large surface — to highly repeatable and precise results for measuring colour and in particular for the Yellowness Index YI E313 for translucent samples,” Hunterlab claims. It adds that, because height positioning of the sensor and the averaging are carried out automatically, the operator does not need to be highly trained so the Aeros is well suited to quality control of plastic pellets during manufacturing.
Managing black Black has traditionally presented acute measure- ment challenges. Surfaces appear black when less than 1% of incident light is reflected, which means that most of the “blacks” we see around us are actually just very dark colours. This means there are all sorts of blacks, each carrying their own under- tones of red, blue, and green. Byk-Gardner recently introduced the spectro2guide Pro spectro- photometer to measure the darkest blacks. “To measure the deepest blacks with a reflectiv-
ity of 0.1% or less, a new approach is required in combination with careful sample preparation to ensure reliable and reproducible quality assurance measurements with a hand-held spectrophotom- eter, as well as a good correlation with our visual assessment,” the company says. Three indices are used to determine how black
a black really is: Blackness (My) is directly related to reflectance without considering undertone; Jetness (Mc) is the colour-dependent blackness value; and Undertone (dM) describes the amount of blue shade (positive value) or brown shades
Figure 1: All blacks carry their own
specific colour undertones. A positive dM (undertone) value indicates a bluish undertone, while a negative value indicates a brownish undertone
The app-based Colorix Nano measurement system can provide colour data from a single granule
(negative value) — Figure 1. “Measurement of the deepest black colours places high demands on a measurement instrument and pushes the technical performance of a handheld spectrophotometer to the utmost limit,” according to Byk-Gardner. It says the high performance of its spectro2guide Pro is based on the use of a high- power LED light source, which provides very good short-term and long-term stability and ensures homogeneous illumination of the measuring spot. “The technical performance of the spectro2gu-
ide Pro is outstanding even on deep black samples with a blackness value My value close to 400,” the company claims. It also claims that the new unit, as well as others in the spectro2guide family, are the only spectrophotometers on the market that can measure colour and gloss as well as predicting the long-term colour stability of a sample. Lightfastness is analysed by the combination of a spectropho- tometer with a fluorimeter.
Source: Byk-Gardner
20 COMPOUNDING WORLD | July 2021
Fake detection Introduced back in 2019, a growing number of industrial customers across diverse markets are now using the Colorix Nano device with its Color Quality Control iOS App, according to company founder David Maurer. “What they like is that they can make colour quality control on a small area of 0.3 by 0.3 mm,” he says. “Being able to measure such a small area allows masterbatch producers to directly control the quality of the masterbatch. It is no longer necessary to melt the masterbatch to have a larger surface to be able to carry out quality control.”
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IMAGE: COLORIX
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