Over the years that I printed colour, I noticed that nearly every paper had a tint that ranged through shades of blue, purple or pink and that this colour was cleared, lightened, dissolved - whatever - if water was applied to the undeveloped paper. I have no real idea what the dye does or where it is located in the layer stack but I suppose a reasonable deduction (at least by someone more interested in making good colour prints than how the material is made) would be that it modifies the sensitivity of one or more layers.

Apart from being in awe of the sophisticated chemistry and precision engineering that goes into making coated photographic products, I care as much about their internal structure as I do about how Intel have engineered the microprocessor chip in my computer. Both classes of product work superbly for my purposes and that is what I pay for.