This paper analyzes the optical dot gain component based on the theoretical description of subsurface scattering of light in paper within the Monte Carlo simulation. The results indicate that the obtained Lorentz shape theoretical function, which describes subsurface scattering, is recognized as a point spread function which is used for the modeling of the reflectance profile of prints by means of convolution. These results were analyzed on prints generated on different papers and digital printing machines. Comparison of measured and calculated reflectance profiles of printed lines and analysis of theoretical models applied show that the point spread function in Lorentz form provides a better description of the point spread function than the hitherto Gaussian form. This simultaneousely shows the validity of the description used in the Monte Carlo simulation. Thus derived the spread function has only one parameter dependance - the profile HWHM w. The influences of numerous relevant factors (composition of paper, printing technique, wavelength of incoming light, coating ...) were theoretically analyzed in detail and compared with measurements, demonstrating the superiority of the description using Lorentz function. Further confirmation of these assumptions was achieved by comparing the results with the ones obtained by the gradient method. The conclusions were additionaly confirmed by analysis of reflectance profile in the frequency domain.