What is offset printing?

The plate works on the mutual repulsion of oil and water. Imaged areas accept greasy ink and repel water; non-image areas hold a thin film of damping solution that keeps ink away. Each colour has its own plate and its own unit, and the sheet passes through them in sequence.

Its advantages are consistency, colour accuracy and cost at volume. Once the press is running, thousands of sheets come off it looking identical, spot and Pantone inks can be matched exactly, and the full range of finishing is available. Print quality on coated board is the reference standard against which other processes are judged.

Its disadvantage is entirely about set-up. Plates have to be imaged and the press made ready before the first saleable sheet, and that cost is identical whether the run is five hundred or fifty thousand. Short runs therefore carry a disproportionate share of it, which is why offset is expensive at low quantities and progressively cheaper as the run lengthens. It also cannot print variable data — every sheet from a given plate is identical by definition.

That is the whole basis of the offset-versus-digital decision, and it is a question of quantity rather than of quality. We will tell you which side of the break-even your job falls on, including when that means the smaller invoice for us.