Degree of fibre distribution uniformity in a sheet of paper. Uniform distribution is described as close formation, while an irregular one is said to be wild formation. Affects ink absorption and thus the printed image.
The uniformity of the distribution of fibers throughout the paper, which could influence the appearance, strength and mottle of the paper
Perfect formation when paper is held to the light has the appearance of ground glass. Poor formation has the appearance of fibre bundles or cloudiness. When they are uniformly distributed, solid ink coverage will go down smoothly. Poor formation may lead to print mottle.