Dispersion Staining, Phase Contrast
G. C Crossmon wrote a paper on the dispersion effects visible with phase contrast illumination
in 1949 followed by K. G. Schmidt in 1958. Phase contrast dispersion staining works best with thin particles, such as asbestos fibers.
It is extremely sensitive and can easily distiguish asbestos fibers in complex matrices. It has the
added advantate of high image resolution and it produces complimentary colors in the same image so
that the wavelength of the refractive index match can be more closely ascertained.
Match at 589 nanometers wavelength
Match at 630 nanometers wavelength, Chrysotile Asbestos Perpendicular to length, Amosite Asbestos Perpedicular to length (650)
Match at 440 nanometers wavelength, Amosite Asbestos Parallel to length
Match at 600 nanometers wavelength, Amosite Asbestos Perpendicular to length, Anthophyllite Asbestos Perpendicular to length (590)
Match at 670 nanometers wavelength,
Match at 530 nanometers wavelength, Optical Glass, Chrysotile Asbestos Parallel to length (540)
Match at 490 nanometers wavelength, Optical Glass Particles, Anthophyllite Asbestos Parallel to Length (480),
Match at 460 nanometers wavelength