Open AccessThe control of amplitude in phase-contrast microscopy
Author(s) -
Edward W. Taylor
Publication year - 1947
Publication title -
proceedings of the royal society of london. series a, mathematical and physical sciences
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.814
H-Index - 135
eISSN - 2053-9169
pISSN - 0080-4630
DOI - 10.1098/rspa.1947.0085
Subject(s) - optics , amplitude , rendering (computer graphics) , contrast (vision) , microscopy , phase contrast microscopy , refractive index , aperture (computer memory) , wavefront , computer science , computer vision , biomedical engineering , materials science , physics , acoustics , medicine
In the past the biologist has generally resorted to differential staining as a means of rendering visible slight non-homogeneities in his preparations. When such treatment was impracticable, as in the case of living cells, the alternatives were to study the out-of-focus image, to illuminate the specimen with very narrow' pencils (with a consequent loss of resolution), or to use dark-ground illumination. Phase contrast offers a means of converting slight changes of refractive index (with the consequent change of wave front) into corresponding changes of amplitude. The method possesses the advantages that the object is accurately focused, that the full aperture of the objective is used and that the eye is particularly sensitive to changes in amplitude. It also makes possible for the first time the detailed study at full aperture of transparent living tissue in place of the usual stained preparations which may have undergone considerable modification in the course of processing.