1.3 Polarization Contrast


An old method commonly used in mineralogy, with equipment that is too expensive for school and hobby use. Appropriate for optically active structures such as trachees and cell membranes, starch grains, anisotropic crystals etc. Very inexpensive transparent polaroid foils can be ordered at Brenner Photoversand, Weiden, Germany. These are cut into appropriately sized pieces, one used as polarizer underneath the condenser, the other as analyzer in the beam path between objective and eyepiece.

trachees in tomato stem
trachees in tomato stem, objective 25x
potassium nitrate
potassium nitrate, objective 10x