The mapping of a surface of constant visual depth in CIELAB colour space

摘要

Independent visual assessments of depth by a panel of four professional colourists were made on dyeings prepared along eight hue directions in CIELAB colour space. From the assessments made, the variation of lightness with chroma for dyeings of uniform depth was mapped along the hue directions. An algorithm was developed to determine the lightness on the surface for any colour of given chroma and hue angle. Whilst direct comparison with the surface defined by the Christ formula for 1/1 standard depth was not possible, it was found that qualitatively the shapes of the two surfaces were very similar. The Christ formula defined greater increases in lightness with chroma in the yellow and lime-green regions than the surface obtained in this work, which may be due to an inconsistency of depth of the 1/1 standard depth samples in this region, as indicated by other depth formulae.