Multiangle visual validation of a physically based rendering of goniochromatic colors

In this work, we evaluate the capability of a physically based rendering framework to reproduce the color flop phenomena of effect coatings through psychophysical tests. For this task, a digitally simulated lighting environment (the Byko-spectra effect light booth) is built to set up the visual tests, in which physical objects inside the physical light booth are visually compared to the rendered images of virtual objects inside the virtual light booth. Two separate visual tests were conducted by judging the color variation on flat and curved metallic painted panels. Fifteen metallic samples were selected in order to cover different hues and color flop values. Both tests show good intra- and interobserver reproducibility. We found that observers are more tolerant when judging curved samples; the acceptability of visualizing the sample colors over various angles was highest at 97% when using curved panels, versus 80% when flat panels were evaluated.