Details:
Summary:
The primary goal of the present research it to establish the variance that can be expected when measuring TAPPI brightness as a traceable metric with a laboratory-grade meter compared to brightness indices measured by production-grade spectrophotometers. It is also recognized that the variance between the analyzed metrics may differ based on the type of paper measured. Therefore, this research also aims to examine the brightness across several types of papers commonly used in the printing and packaging industry. In addition, an important property of many paper substrates known as optical brightness agents (OBAs) is analyzed with a goal of ascertaining its influence on brightness readings among the evaluated instruments and metrics. OBAs are commonly used chemical materials in paper pulp, which can enhance the "brightening" effect on the appearance of the material. After data collection and analysis, it is concluded that the brightness indices from the production-grade instruments used in this study result in higher readings than TAPPI brightness readings. The level of OBAs in the paper is also found to influence paper brightness readings.