An Alternative Quantitative Method of Image Analysis of Rub Tested Printed Packaging (Coating, Printing and Surface Enhancement)

This study compares the development of an alternative quantitative to a traditional qualitative approach for rub testing analysis of printed packaging materials - the test replicating the potential in use or in transit impact of abrasion on the printed surface. The research aims to develop an image-based technique using ImageJ software to quantify the effects of rubbing on printed packaging materials, providing a more precise and objective set of measurements and as such a defined result as compared to qualitative methods. Solid Bleached Sulfate (SBS) paperboard samples were printed using offset techniques with conventional water-based and ultraviolet-cured inline applied coatings. The samples were subjected to rub testing after ambient (+23°C) and ultra-low (-80°C) temperatures to assess the performance of the coatings under different conditions. The qualitative method relied on an experienced print expert review and visual assessments of wear characteristics, while the quantitative method utilised an alternative method using imaging software to measure the greyscale pixel count of the before and after rub test images. The incorporation of image analysis techniques has the potential to facilitate the development of improved standardised protocols for rub testing within the packaging industry, enhancing quality control processes and product consistency. The comparative study reveals insights into the strengths and limitations of both approaches, contributing to a more comprehensive understanding of rub testing analysis for printed packaging materials.