Effect of Colorimetric Attributes on Perceived Blackness of Materials

摘要

While black is one of the most prevalent industrial colors in the world, the colorimetric attributes of what is considered black vary significantly and the range of subtle hue undertones can be numerous. However, no systematic study can be found in the literature pertaining to the potential role of colorimetric attributes in the perceptual assessment of blackness. We have experimentally determined that the perception of blackness is influenced by hue and chroma using psychophysical assessments of a range of black materials. In the initial part of this study a series of 2 × 2 " precision cut glossy Munsell color samples comprising a hue circle with a lightness (L~*) of approximately 20.5 and chroma (C~*) between 4 and 6 were assessed using thirty color normal observers and a filtered tungsten daylight simulator (D65). Observers were asked to arrange samples in order from most like black to least like black with no time limits in three separate sittings. In the second part of the study 27 over-dyed woolen samples were arranged in 2"× 3" dimensions. Samples in this set had a lightness range of 14-16 and C~* of 0.5-3.5, and were assessed by 25 observers in two sittings in the same manner. The third set of samples comprised 24 precision cut 2 " × 2 " dyed acrylic samples with a L~* range of 10.5-12 arranged around the hue circle. Samples were selected such that they comprised three concentric hue circles of eight evenly spaced samples each. The samples were divided into five sets according to chroma: A (C~* = 0.12-0.20), B (C~* = 0.42-0.57), C (C~* = 0.89-0.97), D (C~* = 1.58-1.86), and E (C~* = 3.34-3.46). For the assessment of samples in the third set 100 color normal observers were employed that repeated the assessments in three separate sittings with at least 24 hours gap between each sitting. Analysis of the data indicates that, irrespective of chroma, on average samples with hue angles between approximately 200° and 270° were perceived to be the most black, i.e., cyan to bluish-blacks. Blacks with hue angles above 315° or below 45° (reddish-blacks) were considered to be the least black. Chroma and lightness also influenced the perceived blackness but for the majority of samples the effect was less pronounced.