On the density-dependence of sharpness in thermal print media

In direct thermal print media where image dyes are formed in a layer structure, edge sharpness is observed to be dependent on density, and to be related to internal scattering and reflection. To study the effect quantitatively in various digital print media, a one-step scanner-based methodology was developed to measure MTF and SQF sharpness as a function of density and contrast on a single continuous density edge target. This was used to confirm that a previously described multi- resolution algorithm successfully corrected the density-dependent sharpness loss in direct thermal media.