determination of opacity
The measurements are carried out using a spectrophotometer. In difference to the test methods for paper, such as ISO 2471 or DIN 53146, the method for plastic films uses a white underlay instead of a number of layers of material stacked to complete opacity to determine R∞ and a black underlay instead of a completely black hollow body to determine Ro. An opacity chart (Leneta) type 2 a serves as a black and white base.
Opacity, opaque and/or white pigmented films Method using diffuse reflection, with Leneta opacity card as background. By default, measurements are performed with standard light type D65 under gloss inclusion (SCI). On request, measurements with standard light type D 50 and/or under gloss exclusion (SCE) are also possible. Norm: DIN 6125
Opacity, paper and cardboard Method using diffuse reflection. Ro is measured against a black hollow body, R∞ is measured against a lightproof material stack. By default, measurements are performed with standard light type D65 under gloss inclusion (SCI). On request, measurements with standard light type D 50 and/or under gloss exclusion (SCE) are also possible. Norm: ISO 2471