Short answer
Tone value increase (TVI), the modern name for dot gain, is how much darker a halftone tint prints than the percentage in the file: on newsprint a 50 % dot is aimed to print at about 76 %. Part is physical — ink spreads as it is pressed onto paper — and part is optical, as light scattering inside the paper under the dot's edge. Every printing condition has a standard TVI curve, and profiles and plate curves compensate for it; mismatched TVI is a leading cause of prints that look heavy.
A halftone tint is made of dots covering a fraction of the paper. Mechanically, ink squeezes outward between plate, blanket and paper, so each dot grows. Optically, light entering the bare paper between dots scatters sideways inside the sheet and some emerges under a dot, where it is absorbed; the paper near every dot looks darker than it is. Both effects make the tint absorb more light than its nominal area suggests. TVI is measured as the difference between the effective tone value calculated from the print and the nominal value in the file, and is largest in the mid-tones, where the total dot perimeter is greatest.
Nobody aims for zero TVI; standards define how much there should be, so that files can be prepared for it. ISO 12647-2:2013 introduced a family of lettered TVI curves and assigns them to printing conditions: premium coated uses curve A, uncoated curve C, and non-periodic (FM) screening curve E. Newspapers have much higher gain on absorbent newsprint: WAN-IFRA's guide to the newspaper standard tabulates a curve peaking at about 26 % at 40–50 % tone. The characterisation data already include the standard gain, so a file separated with the right profile compensates automatically.
TVI becomes a problem when it differs from what the separation assumed. A job separated for coated offset and printed on uncoated or newsprint gains far more than expected, so mid-tones and shadows fill in. A press running with too much ink, worn blankets or a different screen ruling produces more gain than the standard; finer screens have more dot edge and so more gain. Digital presses and inkjet have their own characteristics. Printers correct the press side with plate curves that shrink dots before exposure, bringing their real TVI back to the standard curve; designers correct their side by using the profile for the real condition.
TVI is measured on printed tint patches — typically 25 %, 50 % and 75 % of each ink on a control strip — either densitometrically, using the Murray–Davies relation between the tint's density and the solid's, or colorimetrically from CIELAB values. The two methods give slightly different numbers, which is why characterisation data state which one was used. Spread between the three chromatic inks at the same tone (mid-tone spread) matters as much as the absolute value, because unequal gain unbalances greys. Standards set tolerances for both.
| Nominal tone value | Tone value increase |
|---|---|
| 10 % | 11.1 % |
| 20 % | 19.0 % |
| 30 % | 23.9 % |
| 40 % | 26.2 % |
| 50 % | 26.0 % |
| 60 % | 23.8 % |
| 70 % | 19.8 % |
| 80 % | 14.3 % |
| 90 % | 7.6 % |
Why: The press is running above its standard TVI, or the job was separated for a lower-gain condition.
Fix: Printer: check ink density and plate curves against the standard; designer: use the correct condition's profile.
Why: Mid-tone spread: one ink gains more than the others.
Fix: Measure TVI per ink and correct the plate curve for the outlying colour.
Each statement is labelled by kind — established fact, a standard’s requirement, observed market data, a convention, or Colourwise’s own interpretation or analysis — with the strength of the evidence behind it.
StandardStrong evidence
ISO 12647-2:2013 introduced new tone value increase curves and assigns curve A to the premium coated printing condition (PC1), curve C to the wood-free uncoated condition (PC5), and curve E to non-periodic screening.
Source: ISO 12647-2:2013 Graphic technology — Process control … — Part 2: Offset lithographic processes
StandardModerate evidence
WAN-IFRA's guide to ISO 12647-3:2013 gives newspaper tone value increase of 11.1 % at 10 %, 26.2 % at 40 %, 26.0 % at 50 % and 7.6 % at 90 % nominal tone.
Caveat: Trade-body summary of the standard's aim curve, which has its own tolerances.
Source: ISO 12647-3:2013 — quality standard for newspaper production
FactStrong evidence
The ICC registry notes that tone value increase computed colorimetrically will not exactly match the densitometric value for the same print, and records which was used for each data set.
Source: CMYK Characterization Data (registry); IFRA26 characterization data (coldset offset on newsprint)
Reviewed 29 September 2026. Colourwise summarises its sources in its own words and does not reproduce standards text or proprietary colour data. Spotted an error? Tell us.