Before we understand how ink and paper interact, let’s look at the composition of ink and the structure of paper:
The Composition of Ink
Ink is made up of a coloring agent, a carrier body, a solvent that keeps it liquid until it leaves the print head, and various chemical stabilizers. The Coloring Agent may be either a dye or a pigment, regardless of the color. The difference is that a dye is a chemical solution, and the pigment is a mineral oxide, ground exceptionally fine, and put into a chemical compound, both then added to the carrier body.
The Structure of Paper
Paper is made up of cellulose fibers from trees and other like materials. During the making of the paper the fibers form a mesh, with a 60:40 ratio, 60% of the fibers run in one direction, and the other 40% lie at right angles. Paper is also 5% (average) water. If it weren’t it would be as brittle as an autumn leaf. Paper is also chemically treated and finished depending on the end use. For example, newspaper is a very coarse paper, where Bond paper, frequently found in office letters, is a high-grade paper with many finishing chemical additives.
How the Ink and Paper Work with Each Other
Dye-based ink actually soaks into the cellulose fibers, giving a far richer color. The trade-off is that absolute sharpness in not achievable. Pigment-based ink behaves completely differently. The ink is projected at the paper, the carrier body then evaporates, and the pigment adheres to the paper fiber. This results in a clear image, but the color doesn’t have the saturation of dye-based ink.