The silver decoration technique represents a simple and highly sensitive method to visualize lateral structures in Langmuir-Blodgett (LB) monolayers on a large scale. Optical contrast in fatty acid monolayers can be achieved by evaporating a thin silver overlayer with a thickness of 1-10 nm. The resulting contrast depends on the length of the alkyl chain and the packing density of the monolayer. Scanning force microscopic inspections provide a relation between the optical contrast and the effective silver film thickness and surface roughness. A correlation between the local elasticity of the LB film and silver film thickness is observed.