Light micrograph of the epidermis, which is the surface layer of skin. The picture shows two of the layers of skin. The granular layer (lower part of the picture) has cells with many small granules (the small blue dots). The corneal layer (top part of the picture) is made up of pink and light purple keratin substance, which is the material the underlying maturing squamous cells produce. Haematoxylin and eosin stained tissue section. Magnification: 400x when printed at 10cm.