Simultaneous Color and Gloss Measurement for Weathering Testing
Plastics and paints with outdoor exposure are often subject to harsh conditions like solar radiation and temperature and humidity fluctuations that can impact their appearance, functionally, and longevity. Weathering test is necessary to evaluate those impacts, and spectrophotometric color measurement plays an important role in assessing the appearance changes in weathered plastics and paints samples.
The color of plastics and paints is generally assessed using the total color difference dE*. In addition, differences in L* (lightness) and b* (yellowness-blueness) values can be used to obtain more information on yellowing or dirt pick-up.
Gloss is another parameter often measured as it has an overlapping effect with color that influences the appearance of weathered plastics and paints. A sample may look much lighter visually in contrast to its small dE* measurement result due to the loss of gloss on its surface that causes light to reflect in multiple directions (diffuse reflection).
Combining color and gloss measurement can provide a comprehensive assessment of appearance. However, it requires a gloss meter in addition to a spectrophotometer. It is not only costly but also troublesome when it comes to measurement. The need to switch between instruments lengthens the measurement process and makes it difficult to reposition back to the initial measurement spot.
Fast and precise measurement of color and gloss can be done easily with Konica Minolta Spectrophotometer CM-36dG. This innovative spectrophotometer comes with a 60° gloss sensor that enable simultaneous measurement of color and gloss on the same spot. The CM-36dG also comes with a sample viewing function that makes sample positioning easier.
With repeatability within ∆E*ab 0.02 and 0.2GU (10 to 100 GU) for color and gloss, respectively, accurate and repeatable measurements can be expected from the CM-36dG.
The CM-36dG, with its optional Wavelength Analysis & Adjustment (WAA), takes reliability to a whole new level. During each daily calibration, the innovative WAA function analyzes and suppresses any shifts in wavelength due to changes in ambient temperature, etc., enabling worry-free and reliable measurements before sending the instrument for its annual factory calibration and inspection.