It has been found that the L* function defined in the CIELAB color space is not suitable to predict the human visual perception of modulated patterns at high spatial frequencies. For example, in multilevel haiftoning (multitoning), when output levels are equally spaced in L , it has been observed that the visibility ofthe resulting multitone patterns is not uniform across different parts of the...

In order to investigate the performance of suprathreshold color-difference tolerances with different visual scales and different perceptual correlates, a psychophysical experiment was carried out by the method of constant stimuli using CRT colors. Five hue circles at three lightness (L*=30, 50, and 70) and chroma (C*ab=10, 20, and 30) levels were selected to ensure that the color-difference tol...

In this paper, the effect of lightness on blackness preference of 216 black fabrics prepared by printing method is investigated. 18 observers including of 9 males and 9 females are asked to firstly rank order black fabrics with the same lightness values according to their preference. In the next step, observers are asked to define their blackness preference for blacks with different L values. R...

Three replicate trials were conducted to compare sensory descriptive profiles of cooked broiler breast fillets categorized by raw meat color lightness or CIE L* values. In each trial, 20 light, 20 dark, and 30 random fillets (42-d-old birds and deboned at 6 to 8 h postmortem) were obtained from a commercial processing plant. On return to the laboratory, CIE L* a* b* (medial side), pH, and weigh...

The first purpose of this thesis was to design and complete psychophysical experiments for scaling lightness and lightness differences for achromatic percepts above and below the lightness of diffuse white (L*=100). Below diffuse white experiments were conducted under reference conditions recommended by CIE for color difference research. Overall a range of CIELAB lightness values from 7 to 183 ...

Optical lightness is increasingly being used as a proxy for the carbonate content of marine sediment. We compared three measurements of optical lightness, gray scale, brightness and L, to carbonate content to test the reliability of these Ž . measurements as carbonate content proxies. In five piston cores from isotope stages 1 though 6 0–;130 ka , all measures of optical lightness are reasonabl...

 This paper describes the use of image processing to measure lightness changes of fabric appearance. The lightness changes due to dyeing, washing and exposure to light treatments are studied. These properties are measured by using the changes in the intensity levels of the fabrics image and the L* obtained by a spectrophotometer. For each case, analysis of variance (ANOVA) is carded out and the...

To recover surface reflectance and illuminance from the raw luminance signal, the visual system must use prior assumptions and strategies that make use of additional sources of information. Indeed, it has been found that depending on experimental conditions, lightness (apparent reflectance) may refer to judgments that are similar to brightness judgments (apparent luminance), that are similar to...

Instrument values were compared to sensory perception of ground breast and thigh meat color. Different patty thicknesses (0.5, 1.5, and 2.0) and background colors (white, pink, green, and gray), previously found to cause differences in instrument-measured color, were used. Sensory descriptive analysis scores for lightness, hue, and chroma were compared to instrument-measured L* values, hue, and...

Two psychophysical experiments were conducted to analyze the role of color attributes in simple tasks involving color matching and discrimination. In Experiment I observers made color matches using three different adjustment control methods. The results showed that the Lightness, Chroma, Hue (LCH) and the Lightness, redness/greenness, blueness/yellowness ({L, r/g, y/b}) adjustment controls elic...