A method and device for analyzing and treating tonal imperfections on human skin. The method has the steps of providing one or more nozzles and taking an image of skin adjacent the nozzles. A central processing unit calculates a plurality of local L values of the skin near nozzles and calculates a background L. The background L may be the arithmetic average, median, or mean of the plurality of local Ls near nozzles. Skin deviations are areas of skin where the absolute value of the difference between a local L and the background L, ΔLM, is greater than a predetermined ΔLS. Skin deviations are identified by this method and then treated with a treatment composition.
