Bacteriology

both the dyes.

Decolourizer is one reagent used in this process to provide the color differentiation. A decolourizing solution is used to remove the Primary Stain from cells which bind it weakly and then the counterstain (like safranin) is used to provide a colour contrast in those cells that are decolourized.

Lugol's iodine is used as staining solution to detect intestinal protozoa and helminth ova or larvae. It is rapid contrast dye that is added to direct wet mounts of fecal material to aid in differentiating parasitic cysts from host white blood cells. Lugol's iodine stain the protozoan nuclei and intracytoplasmic organelles brown making them easier to identify.