Investigation of Parametric Colour Difference on Physical Size Effect for Sample Pairs with Separation

Present study investigates the use of 1931 and 1964 standard colorimetric observers in colorimetry. It was recommended by the CIE to apply them below and above 4 degrees field of view (FoV), respectively. An experiment was carried out to evaluate parametric colour difference on different physical sizes using a grey-scale method on a display. 280 sample pairs of display colours were assessed 20 times by 46 normal colour-vision observers (mean age 24 years). Sample pairs were selected surrounding the 5 CIE colour centres, having mean colour difference of 4 CIELAB units, with separation between two colours on a pair, having 4 physical sizes, 2 degrees, 4 degrees, 10 degrees and 20 degrees. The visual results were used to test the effects of different colour matching functions (CMFs) and colour difference equations. It was found that CIEDE2000 performed the best, followed by CAM16-UCS and CIELAB the worst. Finally, CIE 1931, CIE 1964, CIE 2006-2 degrees, CIE 2006-10 degrees and 2006-4 degrees CMFs had similar performance in calculating colour differences.