The method used to apply a net of powder to the surface of a condensed monolayer is described in detail. It is shown that photographic records of the now can be analyzed to determine areas of under- and overcompression. By use of a polymer with a plateau in the pressure-area curve, the effect of pressure gradients can be studied in relation to the methods used to compress the film. Examples of the application of the technique are given for three polymers. Poly(butyl methacrylate), which behaves (approximately) as a Newtonian monolayer, is shown to compress fairly uniformly. In contrast poly(L-alanine) and poly(gamma-ethyl L-glutamate) do not flow as Newtonian monolayers and show marked deviations from uniformity of compression. The significance of these results is discussed in relation to the deposition of uniform LB films and in making reliable measurements of surface potential.