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Phase contrast electron microscopy of biological materials
Author(s) -
Unwin P. N. T.
Publication year - 1973
Publication title -
journal of microscopy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.569
H-Index - 111
eISSN - 1365-2818
pISSN - 0022-2720
DOI - 10.1111/j.1365-2818.1973.tb03834.x
Subject(s) - contrast (vision) , phase contrast microscopy , dark field microscopy , phase (matter) , optics , electron microscope , biological specimen , high contrast , phase contrast imaging , resolution (logic) , materials science , field (mathematics) , microscope , microscopy , physics , computer science , artificial intelligence , mathematics , quantum mechanics , pure mathematics
SUMMARY The properties of two electron microscope phase contrast imaging methods are compared. The first is the conventional bright‐field method in which dark phase contrast is created by defocusing; the second is a phase plate method in which bright phase contrast is created by means of a suitably shaped electric field. Using some negatively stained biological specimens which have a well‐known repeating structure as the test object, it is shown that the phase plate method has some important advantages over the bright‐field method. Its contrast transfer characteristics are such that it can provide a more faithful representation of the high resolution detail in the object. Moreover, by producing bright, rather than the normal dark, phase contrast it is able to simultaneously enhance the detail in the specimen and weaken the detail in the stain; this latter property enables the method to display information about the specimen that it would not be possible to detect with the bright‐field method.