Estimating the colors of paintings

Observers can adjust the spectrum of illumination on paintings for optimal viewing experience. But can they adjust the colors of paintings for the best visual impression? In an experiment carried out on a calibrated color moni- tor images of four abstract paintings obtained from hyperspectral data were shown to observers that were unfamiliar with the paintings. The color volume of the images could be manipulated by rotating the volume around the axis through the average (a*, b*) point for each painting in CIELAB color space. The task of the observers was to adjust the angle of rotation to produce the best subjective impression from the paintings. It was found that the distribution of angles selected for data pooled across paintings and observers could be de- scribed by a Gaussian function centered at 10o, i.e. very close to the original colors of the paintings. This result suggest that painters are able to predict well what compositions of colors observers prefer.This work was supported by the Centro de Física of Minho University, by FEDER through the COMPETE Program and by the Portuguese Foundation for Science and Technology (FCT) in the framework of the projects PTDC/MHC-PCN/4731/2012 and PTDC/EAT- EAT/113612/2009, by and the COST-Action TD1201, Colour and Space in Cultural Heritage (COSCH) through Short Term Scientific Missions (STSM): “Hyperspectral imaging on historical manuscripts and natural scenes” (COST-STSM-TD1201- 010813-032699, 2013). Cristina Mon- tagner was supported by the grant SFRH/BD/66488/2009