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DISCRIMINATION BETWEEN BEERS WITH SMALL COLOUR DIFFERENCES USING THE CIELAB COLOUR SPACE
Author(s) -
SMEDLEY S. M.
Publication year - 1995
Publication title -
journal of the institute of brewing
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.523
H-Index - 51
eISSN - 2050-0416
pISSN - 0046-9750
DOI - 10.1002/j.2050-0416.1995.tb00862.x
Subject(s) - mathematics , significant difference , color difference , color space , colorimetry , artificial intelligence , colour difference , limits of agreement , yardstick , chemistry , statistics , optics , computer science , chromatography , physics , medicine , geometry , nuclear medicine , enhanced data rates for gsm evolution , image (mathematics)
Commercial beers which recorded the same colours by either the European Brewery Convention (EBC) Recommended Method or by visual comparison against standard colour discs in a Lovibond Comparator, exhibited qualitative differences in their visible spectra. These differences, in turn, translated into measurable differences in colour, expressed as ΔE a,b , when described by the CIELAB colour system. Visual difference tests revealed that, in some cases, beers with the same EBC colour could be discriminated by observers under ideal viewing conditions. A threshold value for ΔE a,b , (which varied with EBC colour), below which no significant difference in beer colour could be detected by visual comparison, was determined by consideration of the corresponding ΔE a,b , values for these beers. This threshold was used to assess the accuracy of a rapid method for colour analysis which uses transmittance values at five selected wavelengths. This new method was shown to give ΔE a,b values, with respect to a reference method, which were within the limit of visually detectable colour differences. This, therefore, provides a valuable yardstick for assessing the worth of new tristimulus‐based colour measurement techniques and instrumentation.