Photo printing: When inks ain't inks

Common arguments

In general, dyes bind to paper better than pigments and offer superior color reproduction and glossiness, yet they suffer from low fade resistance to light and air (ozone). In addition, colors tend to bleed together when exposed to water.

In the case of pigmented inks, the pigments remain in a solid state when mixed with most liquids. These are dispersed throughout the ink with the use of special additives, preventing the particles from clumping together and sinking to the bottom of the liquid. Still, there's a need for the cartridges to be shaken like household paint to prevent the pigments from clumping together and settling at the bottom (ever squinted at the instructions for Epson's DURABrite ink installations?). Also, because the pigment particles are too large to penetrate the paper coatings, you'll find bumps on the surface of the media.