ISO 12647-2 is the reference that turns good color from an opinion into a target. It is what lets a job printed today match the same job printed next month, or in another plant. Here is what it actually specifies for sheetfed and web offset, without the jargon.
What ISO 12647-2 standardizes
- Substrate classes, with defined paper white and gloss.
- Aim values for the process primaries (cyan, magenta, yellow, black) in CIELAB.
- Tone value increase (TVI) curves, by screening and substrate.
- Gray balance, so neutrals stay neutral across the tonal range.
- Tolerances: how far a production sheet may deviate and still conform.
Why it makes color repeatable
By fixing the targets and the acceptable spread around them, ISO 12647-2 removes the guesswork. Two operators, two shifts or two sites print to the same numbers instead of to personal judgement, which is what makes the result repeatable.
Substrates and ink primaries
Color is always relative to the paper it sits on, so the standard defines substrate classes and the Lab values the primaries should hit on each. Match your paper to the right class first; the rest of the aim values follow from there.
Tone value increase and tolerances
Ink spreads as it transfers and dries, so a 50% dot prints darker than 50%. ISO 12647-2 specifies how much TVI is expected and the tolerance around it. Holding TVI and gray balance is usually what separates a conforming sheet from a near miss.
Printing to ISO 12647-2 in practice
Standardize the substrate and inks, characterize the press, then control each run against the aim values with a color bar and a measurement device. Closed-loop control keeps you inside tolerance from the first sheet to the last, not only at spot checks.