In this paper we address the superposition of digital holograms from two independent perspectives. The first is concerned with the subject of superresolution, i.e. increasing the resolution of a digital holographic system beyond its limit. The limiting factor regarding resolution in a digital holographic system is the pixel size, which is equal to the smallest resolvable unit. By careful superposition of different digital holograms captured of the same three-dimensional object, we attempt to increase the resolution of the reconstructed image and equivalently we attempt to increase the range of angles of reconstruction. We use the Wigner distribution function to qualify the method. The second form of digital hologram superposition is concerned with the construction of synthetic three-dimensional scenes. By adding digital holograms of different objects, at the same or at different distances, we may create a synthetic three-dimensional scene in which both objects are present. We may allow for the fact that one object may occlude the other by multiplying by a binary mask by the occluded objects wavefield at the appropriate numerically propagated distance. Â© 2006 American Institute of Physics.