High-accuracy colorimeters

Citation

(2001), "High-accuracy colorimeters", Pigment & Resin Technology, Vol. 30 No. 4. https://doi.org/10.1108/prt.2001.12930dad.008

High-accuracy colorimeters

High-accuracy colorimetersKeywords: Minolta, Colour, Measurement

Minolta Industrial Instruments offers a wide range of compact tri-stimulus colorimeters for consistent measurement of reflected colour and colour difference in all the standard international chromatic systems (Plate 5). The precision instruments are thought to be ideal for use in design, production and quality control in a wide range of industrial applications, including food, plastics and packaging.

Plate 5 Minolta offers a complete range of high-accuracy colorimeters for a wide range of industrial applications

The Minolta CR-300 Chroma Meter series consists of five models, each with its own novel illumination and viewing conditions, offering a choice from which to select the most suitable model for a given application. Inter-instrument agreement is such that multiple units can be used for colour control both within a company and between companies. The different models offer measuring areas from 3mm diameter to 50mm diameter, d/0° diffuse illumination/ viewing considered suitable for most applications and 458/0° illumination/viewing to exclude the specular component reflected from glossy surfaces.

All models incorporate a measuring head with a pulsed xenon arc lamp for illumination of the subject. The measuring head connects directly to a Minolta DP-301 portable data processing unit. Based on stored data, this unit calculates calibration-adjusted absolute values and colour differences. It can store up to 300 sets of captured data, carry out statistical calculations, be programmed for measurements at regular time intervals and set to alarm above set colour differences. Data are displayed on its 16 character x 2 line screen, whilst a hardcopy can be obtained via the thermal printer. A standard RS-232 port, enabling two-way communication with a PC, enables captured data to be uploaded later for storage, further analysis and reporting, or for control instructions and calibration data to be downloaded to the instrument.

The CR-300 model is designed for non-glossy surfaces and has an 8mm diameter measuring area. The measuring head weighs just 670g. It has reportedly proved particularly successful for colour measurements within the food, plastics and packaging industries, though it is said to be equally at home with finished paint products, for dyed cloth and printed fabrics, for printed posters and for ceramic products such as tiles, porcelain, pottery and glass. The CR-310 is similar, but with a 50mm diameter measuring area it is particularly suited to textured surfaces. Inter-instrument agreement is within 0.6, <E*ab, for the CR-300 and 0.8 for the CR-310.

The CR-321, CR-331 and CR-331C Chroma Meters are all designed for glossy surfaces. The CR-321 has a 3mm diameter measuring area, whereas the CR-331 averages out measurements over a larger 25mm diameter area. The CR-331C, whilst similar to the CR-331, is designed to illuminate and measure products with surfaces which exhibit directional characteristics. Applications for these instruments include finished painted and plastic surfaces, textiles and printed paper materials.

Minolta also offers a number of optional accessories including a versatile interface, the Minolta 1/0-300, for permanent computer connection in place of the DP-301.

Details available from: Industrial Instruments Operation, Minolta (UK) Ltd. Fax: +44 (0)1908 618662; E-mail: twalker@minolta.co.uk