G0 Revisited as Equally Bright Reference Boundary

Brilliance and zero grayness (denoted as G0) and are two terms coined by Ralph Evans. Nayatani, Heckaman and Fairchild have done series of work to incorporate them into comprehensive color appearance models. In this work, those concepts were reexamined to scale lightness/brightness across the chromaticity diagram. Specifically, observers, mostly with a color science background, were asked to adjust the luminance of a color patch to appear with no grayness, or equivalently just about/cease to glow. The hypothesis was that lightness can be equalized across those chromaticities and the Helmholtz-Kohlrausch effect is automatically incorporated. This hypothesis was verified in a follow-up experiment where another group of observers completed paired comparisons of the brightness between the collected G0 results. The G0 task was also repeated under another two levels of adaption backgrounds, based on which different absolute brightness results for a given chromaticity might be derived. In addition, high correlations between the G0 results (as a perceptual boundary between appearance modes) and different physical gamut boundaries including MacAdam's optimal colors were found for possible computational proxies and ecologically meaningful implications.

Comparison of remote and in-person tutorials of color appearance phenomena

Accurately describing the effect of lighting on color appearance phenomena is critical for color science education. While it is ideal to conduct in-person tutorials to demonstrate the color appearance fundamentals, laboratory tutorials have been limited due to COVID-19. The limitation of in-person gatherings and the increase popularity of remote teaching help evoke alternative methods to demonstrate color appearance phenomena. Here, a remote tutorial method is described, and results are compared to in-person tutorials. While the remote tutorial had weaker result in representing observers' color experience compared to the in-person lab tutorial, remote demonstrations can be used to demonstrate and discuss the limitations of color imaging, and the difference between the human visual system and digital imaging systems.

The Development of Three Image Quality Evaluation Metrics Based on a Comprehensive Dataset

In this study, a large scale experiment was carried out to assess the image quality of 2266 images using categorical judgement method by 20 observers. These images were rendered in color contrast, chroma, colorfulness, lightness, and vividness directions. The results were used to derive three No-Reference (NR) Image Quality Estimation Models (IQEMs). The first model was based on color science, (different scales in CIELAB). The second model was a Neural Network model while the third model was a statistics model based on color appearance attributes. Their performances were evaluated using two databases, those developed at Zhejiang University and those available from the public databases in terms of correlation coefficients between the objective and predicted image quality scores.

Digital Textile Ink-Jet Printing Innovation: Development and Evaluation of Digital Denim Technology

This research explored the potential for ink-jet printing to replicate the coloration and finishing techniques of traditional denim fabric and standardized the reproduction and evaluation procedure. Although denim fabric is widely consumed and very popular, one drawback to denim is that the finishing and manufacturing processes are energy and water intensive and can cause environmental hazards as well as generation of pollution through water waste, particularly at the finishing stage. Textile ink-jet printing has the potential to replicate some of the coloration and finishing techniques of traditional denim fabric without negative environmental impacts. A two-phase research project was conducted. In Phase I (P1), an optimal standard production workflow for digital denim reproduction (including color and finishing effects) was established, and six different denim samples were reproduced based on the workflow. In Phase II, an expert visual assessment protocol was developed to evaluate the acceptance of the replicated digital denim. Twelve ink-jet printing, color science, and denim industry experts finished the assessment.

Use The Theoretical Foundations Of Color Science In Teaching Students To Work With Educational Productions From Painting

The article provides students with information about color in painting lessons, a brief history of its development, the basics of color science in teaching students to work with drawings. As a practical exercise, a step-by-step example of painting a still life is given.

On the Mathematical Foundations of Colorimetry: Color-matching, Object Colors and Optimal Colors

The psychophysical description of one of the pillars of color science, the color-matching paradigm, forms the basis of the representation theory of colors. This description entails the weighted integration of a spectral distribution of radiant energy (i.e. a light-ray; ‘stimulus side’) with three color-matching functions (‘observer side’). Here these color-matching functions are conceptualized as a vector-valued measure , which grounds the representation theory of colors in the mathematical frameworks of measure theory and functional analysis. Properties like the convexity and compactness of the tristimulus space and the chromaticity diagram follow readily from this color-matching measure model. Notably also is that within the model metameric colors naturally correspond to -equivalence classes of spectral distributions. Subsequently, an extension of the model is provided for object colors. Among other things, this results in a clear and practical mathematical expression about optimal colors.