Standardization · 2026-09-06

G7 and ISO in plain language: what density and TVI mean for ink

A shop-floor intro to G7- and ISO-style print control — solid ink density and tone-value increase — and how a Hefei distributor can support trials without being a certification body.

G7ISOdensityTVI

What people usually mean by G7 and ISO on a carton press

In packaging conversations, “ISO” often points to process-control ideas in the ISO 12647 family (how a printed sheet should look when the process is in control). “G7” is an Idealliance method that many plants use to calibrate gray balance and tonality so that different presses can share a similar visual result. Both are methods and targets — they are not a stamp HuiRun can sell you.

You do not need to become an auditor to use the ideas. Plants we speak with often start by measuring solids and midtones on their current conventional offset ink, then decide whether the ink, the water, or the curves are the first lever.

G7 and ISO 12647 are related conversations, not identical certificates.
Ask who owns the target: the brand, the printer, or a shared file from a previous supplier.
HuiRun is a distributor in Hefei, not Idealliance and not a national metrology institute.

Solid ink density — what the number is for

Density on a solid patch is a convenient shop number: it tells you how much light the ink film is swallowing on that stock, with that instrument geometry. It is not “color” by itself. Two cyan inks can share a density and still look different if the pigment and the paper change.

When a buyer says “run to G7” or “run to ISO,” they often mean: hit agreed solid densities (and gray balance) rather than printing by eye until the pile looks heavy. Conventional process inks we supply still need your densitometer or spectro, your paper lot, and your fountain — verify locally.

Use the same instrument status (for example T or E) that the target file assumes.
Record paper white; density without a backing story is hard to compare later.
Do not chase a catalog density from a website if your board is much more absorbent.

TVI — tone value increase, not a defect by default

TVI (tone value increase, often still called dot gain in the pressroom) describes how a 50% file tint prints darker on paper. Some increase is expected; the question is whether it is stable and whether your curves compensate. Ink body, water, pressure, and blanket all move TVI.

If midtones fill in after you change conventional ink, do not only blame the tin. Measure a tint ramp on the same board before and after, at the same speed. HuiRun can help you pick a conventional series that plants with similar speeds often run; we cannot declare your TVI “ISO compliant” from a photo.

Measure at least solids and a midtone (often 40% or 50%) on each unit.
Change one variable at a time: ink, then water, then curves.
UV jobs have a different film and a different TVI conversation — do not mix the files.

What HuiRun can support — and what we are not

As a Hefei distributor we can: help you choose a conventional offset ink that is commonly run on carton board; share typical shop ranges from plants we speak with (always verify); and sit in on a trial to read densities with your team. We can also point you to the brand’s TDS.

We are not a certification body. We do not issue G7 qualifications, ISO registrations, or calibrated instrument certificates. If you need a formal audit, hire a qualified consultant or the relevant program. Do not write “HuiRun certified G7” on a carton spec.

Support means materials plus a structured trial — not a plaque on the wall.
We will not invent a target density and call it ISO 12647 without your measured sheet.
Spot colors and brand reds belong in a separate matching loop; see our color-management article.

A practical first week on press

Pick one house board and one four-color job. Print a control strip you can measure. Write down solid densities and one midtone TVI per unit with the current ink. Then trial the candidate conventional ink at the same water settings before you touch curves.

Send HuiRun the press, the board, the instrument type, and whether the buyer named G7, ISO 12647, or only “stable density.” We will propose options we are authorized to quote from Hefei and a trial plan — not a certificate.

Keep wash-up complete; leftover ink in the roller train falsifies the first density.
Save the measured sheet; it is more useful than a verbal “it looks close.”
If the buyer’s file and your press cannot meet both density and TVI, say so early — change paper or curves, not only the tin.

Key questions

What is the short answer?: A shop-floor intro to G7- and ISO-style print control — solid ink density and tone-value increase — and how a Hefei distributor can support trials without being a certification body.
What people usually mean by G7 and ISO on a carton press: In packaging conversations, “ISO” often points to process-control ideas in the ISO 12647 family (how a printed sheet should look when the process is in control). “G7” is an Idealliance method that many plants use to calibrate gray balance and tonality so that different presses can share a similar visual result. Both are methods and targets — they are not a stamp HuiRun can sell you.
How should the numbers in this article be used?: The ranges here are typical shop practice. Confirm them on your press, paper lot, and lamps or dryer. Catalog numbers stay on the data sheet; the signed sheet comes from a trial.

The ranges here are typical shop practice. Confirm them on your press, paper lot, and lamps or dryer. Catalog numbers stay on the data sheet; the signed sheet comes from a trial.