There are three ‘classical’ approaches to portraiture, high key, low key and mid key. Portraiture in these categories is recognised by the difference in the variation and extremes of the tonal range throughout the image. In its simplest form the difference between the three categories is best understood by comparing the style of portraiture to exposure. In a subject with average reflectance ratios, a mid key could be compared to correct exposure, low key to underexposure and high key to overexposure. It is important to remember this is not how the result is achieved. With this visual in mind it is easier to create the lighting required using lighting ratios and exposure interpretation.