Hostname: page-component-cd9895bd7-fscjk Total loading time: 0 Render date: 2024-12-23T23:11:39.220Z Has data issue: false hasContentIssue false

Top Light With The Polarizing Microscope

Published online by Cambridge University Press:  14 March 2018

Walter C. McCrone*
Affiliation:
McCrone Research Institute

Extract

Core share and HTML view are not available for this content. However, as you have access to this content, a full PDF is available via the ‘Save PDF’ action button.

To adequately microscopically characterize opaque particles, and some finely divided, high refractive index, and transparent particles, one must use top light. This can be done with a built-in or accessory vertical illuminator. It can also be done without a vertical illuminator using any PLM with any separate microscope illuminator focusable to a small bright spot. Aimed downward onto the slide preparation at a steep angle, but missing the objective, and with the transillumination subdued or turned off, the color and surface texture of opaque particles can be readily discerned. The objective must have a long working distance, usually, therefore, a 10X or lower magnification.

Pseudo opaque particles (submicrometer particles of high index) are reaify transparent but hey may be colorless or any color. Top light brings out their true color - black, if opaque, but they may be red (Fe2O3), green (CR2O3), yellow (lead-tin yellow) or white (TiO2).

Type
Research Article
Copyright
Copyright © Microscopy Society of America 1994