Unique hue correction applied to the color rendering of LED light sources.

Existing color quality indices for light sources provide broad information about different dimensions related to color quality. Color fidelity, harmony, and gamut area are concepts related to these indices, and industry requests this information. For the last few years, LED light sources have been widely used at home and at work, and now a color rendering index that solves the problem of underestimation of this type of light source is needed to provide a score of subjective assessments made by real observers related to color fidelity. In this work, this problem has been studied in two ways, theoretically and experimentally, and the results show discrepancies between the hue composition calculated theoretically using a color appearance model and hue composition evaluated by real observers. These discrepancies could originate from divergences in the color fidelity score and the subjective evaluation of the naturalness of a scene.

Influence of the correlated color temperature of a light source on the color discrimination capacity of the observer.

It is well known that there are different preferences in correlated color temperature of light sources for daily living activities or for viewing artistic paintings. There are also data relating the capacity of observers to make judgments on color differences with the spectral power distribution of the light source used. The present work describes a visual color discrimination experiment whose results confirm the existence of a relationship between the correlated color temperature of a light source and the color discrimination capacities of the observers.

Crystal Structure of [Ru(terpy)(2)](0): A New Crystalline Material from the Reductive Electrocrystallization of [Ru(terpy)(2)](2+).

Reductive electrocrystallization of [Ru(terpy)(2)](PF(6))(2) (where terpy = 2,2':6',2' '-terpyridine) from an acetonitrile solution containing 100 mM TBAPF(6) results in the formation of black crystals. Crystal data: [Ru(terpy)(2)].(PF(6))(2)[(CH(3))(2)CO], monoclinic, space group P2(1)/c with a = 20.801(2) Å, b = 8.943(1) Å, c = 19.453(2) Å, beta = 92.524(9) degrees, and Z = 4; [Ru(terpy)(2)] (1), orthorhombic, Fdd2 with a = 39.757(4) Å, b = 56.464(6) Å, c = 8.507(1) Å, and Z = 32. X-ray analysis reveals that the crystals consist exclusively of [Ru(terpy)(2)](0) (1), with no solvent or counteranion present in the lattice. [Ru(terpy)(2)](0) units are structurally very similar to the parent [Ru(terpy)(2)](2+), with nearly perfect octahedral symmetry around the metal center and with two terpy ligands that are basically planar. Analysis of the crystal packing shows that [Ru(terpy)(2)](2+) crystals have close intermolecular distances, while [Ru(terpy)(2)](0) crystals show only intermolecular interactions along the c axis with contacts that are less than 3.5 Å. Analysis of molecular volumes and empty spaces reveals the presence of cavities, which could contain substantial electron density.