Topography of Gloss Detailed With the Scanning Electron Microscope

The human observer unconsciously evaluates glossy surface over a wide range of angles with the mind perceiving the specular reflectance to subjectively assess surface appearance. In the paper industry routine gloss is typically measured either at a single angle or with a goniophotometer a profilometer. Each of these instruments measures surface topography. Using the scanning electron microscope, a high resolution definition can record visually the surface topography which gloss measurement tools read numerically. The key to the SEM correlation is to adjust the sample angle in the electron beam to equal the specular angle of the gloss measurement instrument. This technique is especially useful when evaluating high gloss, depth of gloss, or icy gloss.