The Yule–Nielsen effect, also called optical dot gain, is a nonlinear relationship between the reflectance of a halftone image and the fractional dot area of the halftone dots. Two models of the Yule–Nielsen effect are examined. The first is an empirical model previously described in the literature, and the second is an a priori model derived for an idealized halftone line system in one spatial dimension. Both are shown to model halftone behavior well. By combining the two models we derive a semiempirical function that establishes a simple connection between the magnitude of the Yule–Nielsen effect and independently measurable scattering characteristics of the paper. The potential utility of this semiempirical model for characterizing the impact of other factors, such as the shape of halftone dots and depth of ink penetration, is discussed.