Accuracy of metameric indices in relation to visual assessments

Abstract

Metamerism is one of the most fundamental perceptual phenomena of the visual system and has been extensively studied. It can be visualised in terms of two pieces of fabric, a standard and a batch, that match under one type of light, e.g. daylight, but fail to match under another, e.g. tungsten light. This project looks at the agreement between observers on the colour difference of metameric pairs and how the metameric indices for these pairs relates to the visual assessments. Twelve sample metameric pairs were prepared using computer dye recipe prediction and were assessed visually by two methods, one with adaption of the eye to the light source under which the sample was being matched and the second without adaption. There was a low degree of agreement amongst the observers. Poor correlation was observed between the metameric indices, based on both the colour difference and the difference in reflectance curves. and the observer assessments.