The measurement of colour is now an exact science. This is due to the simultaneous evolution of high-quality instrumentation, and high-quality standards to calibrate and control this instrumentation.
This publication outlines the evolution of colour measurement from being an arbitrary and subjective measurement, to being the highly sophisticated and quantitative science that it is today. A central component of this evolution was the development and interpretation of the Tristimulus 3D Model, which is presented and explained in simple terms. However, complexity in colour measurement is due to the fact that different conventions and classifications have evolved that are applicable to different industries.
The chronology of these developments, the key measurement scales and the industry segments where accurate colour measurement is an imperative is presented. Although broadly speaking, the same instrumentation can be used irrespective of the convention or scale of interest, the standards used to calibrate the instrument, control the measurement, validate the test or qualify the instrument, must be specific to a particular scale. Therefore, details of standards specific to such conventions or mandated by ASTM, Saybolt, Gardner, Hazen, and the various Pharmacopoeias are presented. Because of the familiarity of the authors with Reagecon Colour Standards, these are used as examples in this publication.
In addition to specific part numbers, optimal packaging options are also presented. Ultimately, irrespective of the quality or sophistication of the instrumentation, or the technique used, achieving results that are accurate, quantitative and fit for purpose is totally dependent on the quality of the standards. Rather than being prescriptive in any way, this paper is designed to enable the analyst to understand colour measurement and to have enough information to select fit for purpose colour standards.
1.0 Background Theory
2.0 Colour Standards
3.0 Types of Colour Standards
3.1 ASTM Standards
3.2 Saybolt Colour Standards
3.3 Gardner Colour Standards
3.4 Platinum Cobalt Standards (Hazen)
3.5 Pharmacopoeia Colour Standards
Other Papers on Measurement Standards
by John Barron