ISO 105-J01:1997 pdf download – Textiles — Tests for colour fastness — Part J01: General principles for measurement of surface colour.
4 Principle Materials of an opaque or nearly opaque nature (but not translucent) are measured by reflectance methods in order to obtain a numerical representation of the colour of the specimen. NOTES 1 Proper equipment set-up, standardization of the colour measuring instrument and proper presentation of the test specimens to the instrument are required to achieve consistent, reliable and meaningful reflectance measurement results. 2 In general, instrumental colour measurement procedures are dictated by the type of specimen to be measured and the instrument with which it will be measured. Many types of colour measuring instrumentation are available, differing in such features as area-of-view, illumination method, and geometry. The user is cautioned that conflicting results may be obtained on comparisons of data acquired on instruments of different designs. 5 Apparatus 5.1 Reflectance colour measuring instrument, for illuminating a specimen and measuring the amount of light which is reflected from the surface of the specimen. Illumination is usually polychromatic (white light); however monochromatic mode is acceptable for nonfluorescent specimens. Reflectance colour measuring instruments may be broadly divided into two groups: a) Spectrophotometers (typically diffuse/0, using polychromatic illumination) separate and measure the spectrum of light reflected from the specimen relative to a reference white at regular intervals (wavelength intervals of 5 nm, 10 nm and 20 nm are most common). These data may be used to calculate the desired tristimulus values (X,Y,Z) for any given illuminant and observer. Some spectrophotometers (typically 0/diffuse) illuminate the sample with monochromatic light and measure the amount of light reflected from the surface as the sample is illuminated at regular wavelength intervals. b) Colorimeters measure the tristimulus values (X,Y,Z) directly through broadband filters which are designed to produce colorimetric values for one illuminant and observer (typically C/2).