We describe new techniques, based mainly on reactive ion etching (RIE) in o
xygen plasma, to render visible micrometer- or sub-micrometer-sized defects
in transparent barrier films on transparent polymers. These techniques can
be used to characterize and better understand the origins of defects in th
ese coatings on a microscopic scale, as well as for mapping and counting de
fect density on a macroscopic scale (tens of cm(2) or more).