Although methods exist for predicting the color of a spot color ink when it overprints another ink, there is a need for a simplified model for the purpose of previewing that can be used during document creations.The proposed model characterizes each spot color individually and predicts the color of overprinting solids and halftones by linearly combining the reflectances of two colors. Each ink is defined separately in terms of its opacity, and relatively few measurements are required to predict the resulting color of the overprint.The model was evaluated for three different substrates. A 6-color test chart, containing a total of 4550 patches of different combinations of C, M, Y, K and two spot colors, was printed using the offset printing process.The overprint model was applied to predict the resulting colors. Model predictions were compared to the measured data in terms of ΔL*, Δa*, Δb* and CIEDE2000. Average CIEDE2000 values between the measured and predicted colors were found to be below 3, for both the spot colors on all papers.