Printingthrough

Printingthrough is a term used in printing and publishing to describe the visible transfer or appearance of printed ink on the reverse side of a substrate through to the front side, or the appearance of a printed image on one side becoming visible on the other due to ink migration, substrate transparency, or pressure. It is closely related to the concepts of show-through or ghosting and is distinct from bleed-through, which involves ink saturating the paper and becoming visible on the opposite side regardless of surface transfer.

Causes and contexts vary by production and material. Common factors include thin or highly porous papers, high ink solids or dense color, insufficient drying time, excessive printing pressure, and environmental humidity. Printingthrough is frequently encountered in inexpensive newsprint, lightweight magazines, and packaging stock, where paper structure and coating are variable. It can degrade legibility and color fidelity, and in some cases may affect the appearance of an entire print run.

Assessment and management rely on visual inspection and, in professional settings, standardized tests that rate the degree of show-through. Mitigation strategies focus on substrate choice and ink behavior: selecting heavier or coated stock, reducing ink solids or adjusting ink viscosity, improving drying or curing time, and controlling press conditions such as impression pressure and temperature. Barrier coatings or blocking agents can also be used in some workflows, along with humidity control during storage and handling.

In practice, printingthrough is generally considered a defect in commercial printing, though some designers and printers may exploit light show-through for intentional design effects when carefully controlled.