Rheinberg illumination

Rheinberg illumination

[′rīn‚bərg i‚lü·mə‚nā·shən] (optics) An illumination technique used in optical microscopes that is a modification of the dark-field method; the central disk is transparent and colored; an annulus of a complementary color fills the remaining condenser aperture; the specimen is seen in the color of the annulus against the background of the central disk. Also known as optical staining.