OBSERVATION AND MEASUREMENT OF THE APPEARANCE OF METALLIC MATERIALS -PART II - MICRO APPEARANCE

Part I of this article dealt with the appearance of metallic materials observed at a distance of a few meters. This part deals with the appe arance at reading distance. Metallic materials exhibit various appeara nce attributes, including glitter, glints, depth, coherence glitter, b inocular luster, binocular glitter, and binocular mottle. Color dispar ity is proposed as a measure of binocular luster. Metallic materials r esemble grainy photographs, so the method used in photography to quant ify graininess by measuring blending distance is introduced. Objective measures of granularity are proposed as correlates of graininess. The term ''subsurface'' is applied to the apparent ''surface'' lying bene ath the glossy surface. Methods of optical image analysis, such as poi nt spread function, edge spread function, Wiener spectrum, modulation transfer function, and image correlation are proposed to characterize the appearance of metallic surfaces. Polarization and cylindrical pres entation may aid measurements. Binocular attributes of appearance intr oduced here require analysis of the disparity between two points of vi ew. New kinds of pigments may require new methods of measurement. (C) 1998 John Wiley & Sons, Inc.