Phosphor composition having selected surface coatings

A method for producing a color change or color enhancement in a surface of a visible object, comprising:

• (1) placing on the surface of the visible object at least one energy modulation agent configured to emit radiation upon interaction with an initiation energy;
• and
• (2) applying the initiation energy from an energy source to the surface of the visible object;
• wherein the applied initiation energy interacts with the energy modulation agent to generate or enhance light emission or reflectance by said emitted radiation,
• wherein said energy modulation agent has a normal predominant emission of radiation in a first wavelength range (WR1), but under exposure to said applied initiation energy produces a second wavelength range (WR2) to produce the color change or color enhancement in the medium by emitting a resultant output color different from a color that would be expected had the at least one energy modulation agent not been present.