A toner set includes a plurality of toners, at least one toner but less than all toners of the toner set including binder, colorant and fluorescence agent and remaining additional toners including binder, colorant and free of fluorescence agent. At least a first toner grouping and a second toner grouping of the toner set form a combination, the first and second groupings of the combination exhibiting a substantially same color under ambient light conditions upon image formation. The first toner grouping and the second toner grouping of the combination contain a different amount of the fluorescence agent, wherein upon exposure to activating energy, the fluorescence agent fluoresces to cause a visible change in the color of a pattern formed in an image by the first toner grouping as compared to the second toner grouping.