Date of Award
Master of Science (MS)
Packaging helps to preserve, protect, dispense, communicate, and sell a product. Color is a key contributor to the communication and selling functions. In order to achieve a specific color appearance on a given packaging substrate, spot color printing uses custom formulated inks. The standard colorimetric values for solids of spot colors are well defined by either Pantone® specifications, International Commission on Illumination (CIE) L*a*b*C*ho values, spectral data, or with a combination of these. While the colorimetric standards for tints of spot colors exist in the form of digital libraries such as PantoneLIVE or as Color Exchange Format (CxF-4a) data, spot color tints are commonly managed using tone value measurements. Additionally, these spot color inks can be manufactured as mixtures of different combinations of the base pigment inks. This may cause a hue difference in the tints printed with different ink recipes. Some spot colors are also known to exhibit a shift in hue angle at different tint percentages (e.g. Reflex Blue). It is also important to understand this problem from a designer’s viewpoint who is using a digital standard as reference. This study focuses on evaluating the extent and nature of hue shifts in spot color tints. The study is also intended to address how different these hue shifts are from a digital reference commonly used by designers. The second part of the study evaluates the visual perceptibility and acceptability of these hue shifts in spot color tints. Three versions of spot color tints were evaluated – print, PantoneLIVE, and hue-corrected. The visual results were also correlated to the results obtained from spectrophotometer measured data. The results suggested high hue shifts with spot colors that had a high chromaticity. The study also highlighted the limitations of hue angle and hue difference in characterizing hue shifts for colors with low chromaticity. The visual study showed that there were visually perceivable and potentially unacceptable hue shifts between the tested spot color tints. Although the visual difference between print and PantoneLIVE samples was consistently recognized by the observers, it was not enough to change their intent to purchase in most of the cases.
Rana, Himanshu, "Evaluating Hue Shifts in Spot Color Tints in Flexographic Package Printing" (2020). All Theses. 3316.