Carbon Black Color Measurement with Spectrophotometer

Carbon black, a highly engineered material, has woven itself into the fabric of various industries, leaving its mark on everything from coatings and automobiles to plastics and many more. Commonly used as a pigment, its applications are vast, and its color is not just a visual attribute but also greatly contributes to a product’s functionalities like UV resistance, electrical conductivity,

Measuring Carbon Black Color: Blackness, Jetness, and Undertone

Color measurement instruments like spectrophotometers are commonly used in the measurement of color as they provide a standardized way to quantify and represent the color of an object or material. Spectrophotometers operate on the principle of spectrophotometry, which involves measuring an object’s spectral reflectance or transmittance across the visible spectrum. These spectral data obtained from the spectrophotometer are then integrated by multiplying them with the color-matching functions to obtain the tristimulus values X, Y, and Z. These values provide a numerical representation of color and can further be converted into various color spaces and indices like CIE L*a*b*, whiteness index (WI), etc.

The colorimetric properties of carbon black, used in applications like plastic and coating, can be assessed by measuring the blackness value (M_Y), the jetness value (M_C), and the undertone value (dM). These parameters, outlined in international standards like ISO 18314-3 and DIN 55979, are determined from tristimulus values X, Y, and Z through mathematical formulas.

The blackness value (M_Y) is determined from the tristimulus Y value, solely indicating the level of blackness without regard for undertones.

On the other hand, the jetness value (M_C) is hue-dependent, whereby a deep black color with a bluish undertone yields a higher jetness value (M_C) than one with a brownish undertone.

The difference between the blackness value (M_Y) and the jetness value (M_C) provides further insight into the undertone where the positive undertone value (dM) expresses the amount of blue undertone, and the negative undertone value (dM) describes the brownish undertone level.

Spectrophotometers are available in different measurement geometries like 45°/0°, d/8°, and more. When it comes to measuring the colorimetric properties of carbon black, the choice of measurement geometry relies on the specific application and the texture of the sample surface. For example, the 45°/0° geometry is commonly employed to measure glossy, deep black samples, and the d/8° geometry is better suited for samples that are not as intensely black and have matte or highly structured surfaces. However, if the d/8° geometry were to be used to measure glossy, deep black samples, it should be carried out in the Specular Component Excluded (SCE) measurement mode.

Konica Minolta Color Measurement Instruments and Solutions for Carbon Black Measurement

Konica Minolta Sensing, a leading provider of color measurement solutions, offers a diverse range of spectrophotometers that are utilized across various industries for color development and quality control purposes. Among these, the 45°/0° Spectrophotometer CM-25cG and d/8° Spectrophotometer CM-26dG are notable for their reliability and accuracy in color measurement. Both the Spectrophotometer CM-25cG and Spectrophotometer CM-26dG can be paired with the color management software SpectraMagic NX or SpectraMagic NX2 to facilitate the creation of the blackness (M_Y), jetness (M_C), and undertone (dM) parameters. This combination of instruments and software allows for reliable and reproducible evaluation of the colorimetric properties of carbon black samples.

The Spectrophotometer CM-25cG and Spectrophotometer CM-26dG also come with an integrated 60°, allowing for color and gloss to be measured simultaneously. Check out the CM-26dG and CM-25cG videos for a closer look at their functionalities and features.