Lightness And Luminance: Perceptual Qualities in Conditions Of Simultaneous Contrast

This article is devoted to the research of the influence of induction and crispening effects on the lightness of objects. The target of this research is to simplify and clarify the analysis of the light distributions derived from the results of lighting calculations and measurements, and also to form the recommendations for obtaining preferred lightness contrasts in the case of visual perception of objects on different backgrounds. To provide such possibilities, it is necessary to refine the model of the lightness calculation in modern colour appearance models, which, in turn, requires the results of new experiments to take into account the induction and crispening effects in the conditions of simultaneous contrast. The same experiment was established by Takasaki on visual perception of grey squares on grey backgrounds. The article substantiates the necessity to refine the results of the Takasaki experiment and conduct the new experimental approach in more strictly specified conditions and in the expanded luminance range to ensure conditions of the modern standards. Here we propose setting up an experiment that provides these refinements and considers the properties of the proximal field – the contour of objects. The search of the results uses multi-objective optimization methods. The first results of this experiment are presented, based on them, were formed proposals to determine the preferred luminance of objects to ensure the required levels of lightness contrast when working on specified backgrounds. The calculations of the lightness deviations obtained as the result of the experiment and in the CIECAM02 colour appearance model, are presented. The peculiarities of translations of lighting engineering literature in the field of modelling a light-colour environment are noted, which require clarification for a correct and reliable understanding of colour appearance models, for which is proposed to open a discussion on this subject.

Combining emissions of hole- and electron-transporting layers simultaneously for simple blue and white organic light-emitting diodes with superior device performance

Combining emissions of hole- and electron-transporting layers simultaneously, a simple four-color hybrid white OLED realizes good white emission with a maximum CRI of 93–94 over a wide luminance range of 83.68–17 050 cd m−2, and also achieves a high EQE of 18.44%.

A novel bipolar phosphorescent host for highly efficient deep-red OLEDs at a wide luminance range of 1000–10 000 cd m−2

A novel bipolar phosphorescent host FPYPCA with narrow Eg as well as high T1 realizes the most efficient deep-red PhOLED (R1–15), which maintains very high EQEs of >23% at rather high and wide luminance range of 1000–10 000 cd m−2.

The role of local framework luminance range in the simultaneous lightness contrast illusion with double increments

In double increment Simultaneous Lightness Contrast two equiluminant squares rest on darker backgrounds that differ in luminance. Research on such displays has produced conflicting results as to whether an illusion is observed. Anchoring theory of lightness predicts no illusion with double increment displays. Here we test the hypothesis that an illusion can be predicted if the framework containing the target and the darkest background carries more weight in lightness computations. We tested two displays, one with a general white and one with a general black background. An illusion was obtained only in the first display. These results suggest that an illusion can occur with double increment displays when the global value of the targets differs from their local value, as these conditions allow different local framework weighting to affect the targets? final lightness. We propose that this parameter be added to the Anchoring Theory.