Printability analysis of PLA films using flexographic solvent-based ink according to ISOspecifications

This study analyzes the influence of photopolymer plate hardness and mounting tape on print quality in flexography, with a focus on evaluating the optical and colorimetric parameters of prints on white PLA film. The experiment was carried out in six variations of printing: two hardness of polymer plates in combination with three hardness of mounting tapes. A test image was printed using solvent cyan ink and all key print quality parameters were analyzed, including ink density, tonal values, and CIELAB values in accordance to ISO 12647-6:2012 standard. The results showed that combinations using the softer plate with harder tapes provided the optimal balance between halftone precision, solid density, and colorimetric accuracy. Combinations using the harder plate resulted in lower ink transfer but also less dot gain. Microscopic analysis revealed that combinations of harder plates with softer tapes led to lower ink film uniformity. The study provides useful guidelines for optimizing flexographic printing on PLA substrates.