Standard Practice for Calculating Yellowness and Whiteness Indices from Instrumentally Measured Color Coordinates

Importancia y uso:

5.1 This practice should be used only to compare specimens of the same material and same general appearance. For example, a series of specimens to be compared should have generally similar gloss, texture, and (if not opaque) thickness, and translucency.

5.2 For yellowness measurement, this practice is limited to specimens having dominant wavelength in the range 570 nm to 580 nm, or Munsell hue approximately 2.5GY to 2.5Y. For whiteness measurement, this practice is limited to specimens having Munsell value greater than 8.3 (CIE Y greater than 65) and Munsell chroma no greater than 0.5 for B hues, 0.8 for Y hues, and 0.3 for all other hues (see 3.3.1).

5.3 The combination of measurement and calculation leading to indices of yellowness or whiteness is a psychophysical process, that is, the procedures specified are designed to provide numbers correlating with visual estimates made under specified typical observing conditions. Because visual observing conditions can vary widely, users should compare calculated indices with visual estimates to ensure applicability. Some standards addressing the visual estimation of color and color difference are Practices D1535, D1729, E1360, and E1541, and Guide E1499.

5.4 This practice does not cover the preparation of specimens, a procedure that may affect significantly the quantities measured. In general, specimens should be prepared and presented for measurement in the manner that is standard for the test being performed. Select enough specimens or specimen areas to provide an average result that is representative of each sample to be tested. See Practice E1345.

Subcomité:

E12.04

Referida por:

E1247-12R23, D4020-18, D4020-18, E0284-25, D5237-14R24, D4008-19R24, D7133-21, C1900-24, D8584-24, F0942-18R23E01, D4960-20, D5386-24, E0805-22, D6290-19, D6605-06R24, D8087-18, D4101-24, D3730-17R22, D6763-16R22, D7942-15R23, D6290-19, D6290-19, G0178-16R23, D5146-10R19, E0308-22, D6290-19

Volúmen:

06.01

Número ICS:

17.180.20 (Colours and measurement of light)

Palabras clave:

color; colorimetric analysis; color/light; instrumental measurement; reflectance; reflectivity; whiteness indexes; yellowness indexes;