My science back ground starts asking all kinds of questions. It's clearly an energy thing. Emitted light energies ect. One way I would try to get a handle on it is to create some sort of gradation of substances and observe the effect. But I didn't think you were a scientist so that may not be you cup of tea. It may not be mine either! I think one problem you will encounter is that different plants may well bew colored different colors although they are at the same temperature. Because I gather that the IR filter is not actually temperature sensitive but Infra Red Energy dependent. OK. How about this can you photograph water, fruit juice, and rusty water. And wood, concrete, and plastic? Please, please, oh pretty please? I simply have to get me oine of those IR filter things!! Buy the way any ida how one develops IR film? Nplus, Alpha, somebody. Bsteph