The Optical Society of America Uniform Color Scales (OSA-UCS) possesses many salutary properties, but it is presently under-utilized. The authors believe the reason may be that the transformation from CIE notation to the OSA system presently has no known inverse. In an effort to rectify that lack, the OSA system is presented in its forward transformation, and then an inverse transformation using a NewtonRaphson iterative algorithm is described. The authors' experience with parameters associated with implementing the algorithm is related, and a few worked examples are provided to assist potential users in their implementation. (c) 2011 Wiley Periodicals, Inc. Col Res Appl, 2012; Published online 13 July 2011 in Wiley Online Library (wileyonlinelibrary.com). DOI 10.1002/col.20684

An additive approach to predict harmony for three-colour combinations is proposed in this article. It is hypothesised that a three-colour combination can be seen as a combination of three colour pairs, each generating a harmonious/disharmonious feeling that can he quantified by a two-colour harmony model the authors previously derived; the average of these three harmony values can then determine the overall harmony. To establish whether this hypothesis was valid, two psychophysical experiments were conducted in the United Kingdom and the United States. Experiment 1 used 6545 three-colour wheels as the stimuli, presented individually on a calibrated cathode ray tube display. Under the same viewing conditions, Experiment 2 used 111 interior images as the stimuli. In each experiment, 20 British and 31 American participated as the observers. An additional test was undertaken, with 64 observers taking part, to address the issue of large sample size as encountered in Experiment 1, using 90 colour wheels selected randomly from those used in Experiment 1. The experimental results show close agreement between the observers' response and the harmony value predicted by the proposed method, with a correlation coefficient of 0.71 for the 6545 colour wheels, 0.93 for the 111 interior images and 0.88 for the additional 90 colour wheels. The results support the additive approach as a simple but robust method for predicting harmony in any three-colour combinations, which may also apply to combinations generated by any number of colours. (C) 2010 Wiley Periodicals, Inc. Col Res Appl, 36, 355 372, 2011; Published online 23 June 2010 in Wiley Online Library (wileyonlinelibrary.com). DOI 10.1002/col.20624

Computer graphics hardware and software is used to create a new set of tools for selecting a household paint color. Important surface reflection effects, such as gloss and pearlescence, are rendered in real time using pixel shading hardware. Unlike traditional paint chips, this feature permits colors to be evaluated on three dimensional shapes and in different surface finishes. A novel set of color navigation tools is provided to allow the user to visualize the color collection supplied by the manufacturer, to select subsets of the collection for consideration, and to match or modify an existing color sample. This interface is easier to use and less expensive to produce than the fan deck found in most paint stores. The pictures produced by the software are displayed on a four panel video wall. The large size of the wall allows the user to evaluate the appearance of the color at a scale similar to its final dimension once it has been applied to a surface.