Two wavelength coherent imaging is a digital holographic technique that offers several advantages over conventional coherent imaging. One of the most significant advantages is the ability to extract 3D target information from the phase contrast image at a known difference frequency. However, phase noise detracts from the accuracy at which the target can be faithfully identified. We therefore describe a method for relating phase noise to the correlation of the image planes corresponding to each wavelength, among other parameters. The prediction of the phase noise spectrum of a scene will aid in determining our ability to reconstruct the target.