Color printing using halftoning techniques is becoming ubiquitous on the desktop. Accuracy and consistency of the color printed by these devices depends on, among other things, the optical properties of the paper. The general influence of light scattering within the paper has been known for half a century, but calculation of the effect on the color gamut is complex and depends on the details of the paper optical spread function and of the halftone pattern. Two limiting cases are analyzed, no-paper-scattering and complete-paper-scattering (optical paper spread function is much larger than the halftone cell size). Simple models are presented for the limiting cases of halftone printed color images, and the predictions are compared with measurements of single-colorant samples from a wax thermal printer. Results show that the simple models bound the single-colorant colors produced by the wax thermal printer. The simple model predicts that the major effect of the paper scatter on single-colorant images is the shifting of colors along the CIE L*a*b* locus. This can result in color differences for the two scattering extremes of 20 CIE L*a*b* units for the same fractional dot area. Two different CIE L*a*b* loci are computed for the same colorant, under the no-light-scattering versus complete-light-scattering conditions, but this is a much smaller effect.