Microholography is a sensitive technique for the detection and visualization of the separation phenomena appearing in an emulsion. For different but close compositions, emulsions can display various physical behavior such as decantation or demixtion that can be evidenced by this technique. We give here the static response, which is the description of a heterogeneous medium containing a size-dispersed component. It is shown that the microholographic technique, which gives a 3-D representation of a particle system, is much more powerful than the techniques usually used.