Advances in Gloss Measurement

Gloss is a common appearance attribute used to describe a product’s appearance. However, the visual appearance of a product cannot be adequately described using gloss. Two surfaces can have identical gloss readings but very different visual appearances and reflected image quality. This discrepancy is due to the limitation of gloss meter technology in detecting rough (orange peel) or microscopic structures (haze) on the surface.

Reflection Haze

Reflection haze can cause the surface to have poor reflected image contrast with halos around it. It is caused by the micro textures on a coated surface changing the direction of reflected light. Some of the potential causes of reflection haze are poor dispersion, raw material incompatibility, and polishing or abrasion.

Orange Peel

The term “orange peel” is used to define a bumpy and rough surface texture caused by incorrect formulation or poorly applied coating. This undesirable texture distorts reflected light, causing a fuzzy reflected image on the surface. Both Distinctness of Image (DOI) and Reflected Image Quality (RIQ) parameters are capable of quantifying orange peel, with the latter having a higher resolution that correlates with human perception.

As shown in Figure 1, the two panels exhibit vast differences in terms of their appearance but marginal differences in their gloss readings. However, when further analyzed using the HAZE, DOI, and RIQ parameters, we can see that panel A is exhibiting higher haze and poorer reflected image quality.

Moving beyond gloss measurement, additional appearance parameters like HAZE, DOI, and RIQ are necessary to obtain a comprehensive product appearance evaluation.

Appearance meter like Rhopoint IQ-S is able to measure gloss, HAZE, DOI, and RIQ simultaneously, providing a cost-effective solution to visual appearance measurement.