The author develops a simple numerical model to relate oxygen consumption within a paint or plastic film to the rate constant and diffusion constant. An approximate relation is deduced for the oxygen starvation depth (the depth where the oxygen concentration falls to 1/10th of its surface value). A generalized curve of oxidation versus depth (embracing two theoretical formulae and the numencal experience from the author's algorithm) appears in the text, together with tables of permeabilities to oxygen and starvation depths for various materials. The author considers the possibility of coating a paint surface with a varnish highly impervious to oxygen to reduce the rate of oxidation of an aged drying oil film