The use of linear scales in the photography of skin lesions

In medical photography linear scales are widely used to monitor change in size. Although accuracy on the image is generally accepted as being perfectly adequate, there is a degree of uncertainty. This led the first author to investigate the use of linear scales when photographing skin lesions at the Victoria Hospital, Kirkcaldy. Established methods of determining photographic accuracy are by themselves insufficient: the outcome must relate to how the end product is used, i.e., by visual assessment and/or manual measurement. As well as showing that the accuracy concerned is adequate for current requirements, this work presents a definitive value.