It does, however, have the major disadvantage that a great deal of training and experience are necessary for best use.
One might consider that becoming a competent microscopist is equivalent to learning to play a musical instrument well.
Those individuals, properly trained, are able to extend the observation and interpretation of large (macroscopic) objects down to subnanometer objects difficult to identify by any other means.
The PLM, by producing enlarged images and by examining samples between polarizing filters, makes it possible to see, isolate, identify, measure, interpret, and evaluate microscopic objects (Chamot and Mason 1958; Hartshorne 1960).
Only a very few individuals and industries maintained their expertise in this nearly abandoned field.