Other eosin mixtures are sometimes used, such as EA50 and EA65. These stains are primarily used for cytology, and in addition to eosin Y, include light green, yellowish, and bismarck brown. The addition of these two dyes provides for the variations in color from pale blue to pink cytoplasm, best noted in the squamous cells of a pap smear. The concentration of the mixture determines the designation of 50 or 65.