The process includes measuring flops of a layer of the coating composition applied over a test substrate of a mottling prediction device of the present invention at the start and then after a desired time interval. A delta flop is determined by subtracting from the flop at the start from that after the desired time interval and a degree of mottling of a coating resulting from the layer is visually assessed. The process is repeated with varying amounts of one or more rheology additives added to the composition and the degree of mottling vs. delta flop is plotted on a graph and then by using a curve fitting equation, a mottling prediction curve is obtained. By measuring the delta flop of a wet layer of a target coating composition, the degree of mottling in the target coating composition can then be predicted by using the mottling prediction curve.