A method and device for analyzing and treating tonal imperfections on human skin. The method has the steps of taking at least one background image of at least 10 &mum2 of skin and calculating the average background L value of the image on a grey scale. One or more treatment images of the skin are taken and at least one localized L value of individual pixels or group of pixels is calculated within the treatment image. The local L value is compared to the background L value. Skin deviations are areas of skin where the absolute value of the difference between a local L and the background L is greater than a predetermined &DgrLS. Skin deviations are identified by this method and then treated with a treatment composition.
