G7 COLOUR MANAGEMENT

G7 colour management

What G7 is, what it is not, and what a G7 calibration actually involves on a real press. Written by a certified G7 Expert working from the UAE.

What G7 is

G7 is a calibration method. It defines how the neutral greys and the tonal response of a printing process should appear, so that the same file produces the same visual result on different presses and different processes.

Two things carry the method. Grey balance fixes the combination of cyan, magenta and yellow that should produce a neutral grey on your press and substrate. The neutral print density curve, usually shortened to NPDC, fixes how that neutral progresses from highlight to shadow. Get both onto target and prints from an offset press, a flexo press and a digital press begin to look like each other.

That shared appearance is the whole point. It is why a brand can move a job between suppliers, or between a proof and a production run, without renegotiating what the colour should look like.

G7 and ISO 12647 are not the same thing

This causes more confusion than any other point, so it is worth being precise.

	ISO 12647	G7
What it is	A set of process standards with target values	A calibration method for appearance
Defines	Solid ink colours, tone value increase, substrate	Grey balance and neutral tonal response
Question it answers	Are my measurements within the specified values?	Do my greys and tones look right and match across processes?

They are complementary, and many plants work to both. A press can be calibrated to G7 and also held to ISO 12647 solids. Neither one replaces the other.

What a G7 Expert does

A certified G7 Expert is an individual who has been examined on the methodology and is qualified to apply it and to submit qualification work. The certification is held by the person, not by the plant.

On site, the work is usually some combination of:

Characterising the press as it currently runs, before changing anything
Calibrating tone and grey balance onto the G7 curves
Verifying the result on a live job, with measurements the customer will accept
Setting tolerances that the press can genuinely hold on that substrate
Training operators so the calibration survives after the visit

The last point decides whether the project was worth doing. A calibration nobody maintains drifts back within months.

How the work runs

Stage	What happens	What you end up with
Fingerprint	Print and measure a test form under normal production conditions	An honest picture of what the press does today
Calibrate	Correct tone and grey balance towards the G7 targets	Curves applied in the RIP or plate workflow
Verify	Run a real job and measure it	Evidence the calibration holds in production
Sustain	Routine measurement, records and operator training	A process that stays on target

Fingerprinting first is not a formality. Calibrating a press without knowing what it was doing beforehand hides the real problem, which is often mechanical, and produces a correction that will not hold.

Where it applies

The method is process independent, which is its strength in packaging where one brand colour may be produced several different ways:

Offset, both sheetfed and web, where G7 is most established
Flexographic printing, where plate screening and anilox specification interact strongly with the calibration
Gravure, where cylinder engraving and ink behaviour set what is achievable
Digital, where calibration is quick to apply but still needs verifying on the actual substrate

Substrate matters more than process in flexible packaging. The same calibration on white film and on metallised film will not give the same appearance, and pretending otherwise is how colour arguments start.

What G7 does not do

It does not fix mechanical problems. Worn anilox rolls, bearer pressure, tension control and impression setting all sit underneath the calibration, not above it.
It does not extend gamut. If a brand colour sits outside what your inks and substrate can reach, calibration will not put it inside.
It does not remove the need for measurement. A calibrated press that nobody measures is simply a press that was once calibrated.
It is not a certificate for the company. The qualification is personal, and plant level qualifications are a separate programme with their own requirements.

Frequently asked questions

What is G7 in printing?

G7 is a calibration method that defines how neutral greys and tonal response should appear, so that different presses and different printing processes produce a visually similar result from the same file. It works through grey balance and the neutral print density curve.

Is G7 the same as ISO 12647?

No. ISO 12647 is a set of process standards with target values for solids and tone value increase. G7 is a method for calibrating appearance through grey balance and tonal response. They are complementary and many printers work to both.

What does a certified G7 Expert do?

A G7 Expert is examined on the methodology and qualified to apply it. In practice that means fingerprinting the press, calibrating tone and grey balance, verifying the result on production work, setting achievable tolerances and training the team to maintain it.

Do I need to buy new equipment for G7?

At minimum you need a spectrophotometer and the ability to apply curves in your RIP or plate workflow. Beyond that it depends on your current process. Advice on what suits your plant should come before any purchase, not after.

How long does a G7 calibration take?

Fingerprinting and calibrating one press is normally a short on site exercise. The part that determines success is what follows: verification on live jobs, a measurement routine operators can run every shift, and records that show whether the press is holding.