Ink by the Square Metre: A Coverage Rule That Predicts Ink Use per Thousand A4 Pages Within a Stated Dot-Gain Allowance

This paper addresses a practical question in A4: printers quote jobs by pages, impressions or hours, yet the consumable that varies most between jobs is ink, and ink use is governed less by page count than by how much of each page is covered. Using a self-contained computation from stated assumptions, the study evaluates the options across the range a small operation ordinarily meets and identifies the point at which the balance of cost, quality and material use changes. The headline findings are that ink kg per 1000 at 20pct is 0.017; cost usd per 1000 at 20pct is 0.3; ink kg per 1000 full coverage is 0.076; cost usd per 1000 full is 1.37; pages per kg at 20pct is 58824. These figures come from a simulation study: the work is SIMULATED, NOT MEASURED, no physical trials were performed, and every number reported is taken from the deposited computation output so that any reader can reproduce or refute it with local values. The practical value of the result is a rule that can be applied at the point of work without further calculation, together with the tabulated cases from which the rule was derived and a statement of the assumptions on which it depends. Where the computation shows that a widely used practice wastes money or material, that finding is stated directly; where it shows that a popular economy is genuine, the size of the genuine saving is stated with equal directness, so that effort can be directed to the economies that are worth having.