Three-dimensional Modelling of Paper Structure: Optical Properties of Paper and Print.

Three-dimensional models are developed for the structure of paper and for the detailed interaction of light with paper. The models are used in Monte Carlo simulations of the propagation of light in paper. The simulations are spatially and spectrally resolved and allow for features such as different structure in different layers of the paper as well as for ink printed on the paper. The models are used in numerical experiments in which individual structural parameters are changed and the effects on the optical properties of the paper studied. It is shown that both the detailed distribution of ink on and in the paper and the choice of model for the paper structure are important for modelling of print through and optical dot gain.