Pigment Selection for an Inkjet Ink Set with Balanced Lightfade Performance

Abstract

Careful pigment selection for an inkjet printer can achieve balanced lightfade performance. When a print fades from light exposure, commonly each colorant fades at a different rate. This results in an unwanted hue shift in addition to the overall loss in density. In a balanced system, each colorant fades at approximately the same rate. As a result, the amount of hue shift is reduced. The faded print is perceived as less objectionable to the user when the original hues are maintained. In order to create a balanced system, samples are printed with pigment and pigment blend candidates on a variety of media types. Those samples are exposed in a lightfade chamber, and density changes are measured over time. This data is used to select candidates with similar lightfade performance for each colorant of the system. Instead of attempting to maximize the lightfade performance of each colorant, other desirable performance attributes can be considered, such as chroma and cost. The achievement of a balanced lightfade system results in a more complete solution to the customer.