Microbiology staining procedures are not standardized and they depend on standard operating procedures of individual laboratories and the experience of the personnel conducting the staining procedure. Intensity of staining depends on the period of immersion in the dye. Depending on personal requests and standard laboratory operating procedures, sample processing and staining can be carried out according to other protocols.
Gram's iodine is used in Gram staining procedure to differentiate gram positive and gram negative organisms. Gram's iodine acts as a mordant that causes the crystal violet to penetrate and adhere to the gram –positive organisms.