The Neugebauer approach to modeling color cmy halftones generally has to be modified in order to correct for the Yule-Nielsen light scattering effect. The most common modification involves the Yule-Nielsen “n” factor. A less common, but more fundamentally correct modification of the Neugebauer model involves a convolution of the haltone geometry with the point spread function, PSF, of the paper. The probability model described in the current report is less complex than the PSF convolution approach but is still much less empirical than the Yule-Nielsen “n” model. The probability model assumes the Neugebauer equations are correct and that the Yule-Nielsen effect manifests itself in a variation in the XYZ tristimulus values of the eight Neugebauer primary colors as a function of the amounts of c, m, and y printed. The model describes these color shifts as a function of physical parameters of the ink and paper which can be measured independently. Experimentally the effect is easiest to see in the shift in the color of the paper between the halftone dots, and experimental micro-colorimetry is presented to verify the model.