Short answer
Every ink is a colourant carried in a vehicle, but each printing process needs a very different vehicle: offset uses a stiff paste that a rubber blanket can split, flexography a fluid ink metered by an engraved roller, and inkjet a thin liquid fired as droplets. The colourant choice — dye or pigment — then largely decides permanence: dye inkjet prints fade and bleed far more readily than pigment prints.
An ink has two jobs: carry colour to the surface, then stay there. The colourant is a pigment dispersion or a dissolved dye; the vehicle is everything else — oils, resins, solvents or water, and additives that control flow, drying, wetting and rub resistance. Pastes are used where ink is transferred by rollers and plates, liquids where it is metered or jetted. Because the vehicle decides how the ink leaves the press and how it binds to paper, film or board, the same pigment may appear in several very different ink types, and the same printed colour may behave differently on coated and uncoated stock.
Offset lithography prints from a flat plate on which image areas accept ink and non-image areas reject it — traditionally by dampening with water, or in waterless offset by an ink-repellent silicone layer. The inked image is transferred (offset) to a rubber blanket and then to paper, which needs a tacky, viscous paste ink. Flexography is a relief process: a raised rubber or photopolymer plate is inked from an anilox roller whose surface is covered with tiny engraved cells, and a doctor blade scrapes off the excess so a controlled film reaches the plate. That calls for fluid, fast-drying water-based, solvent-based or UV-curable inks, and makes flexo the workhorse for packaging, labels and films.
Inkjet printheads fire droplets through nozzles, so inks must be thin, stable and unable to clog. Aqueous inks use either dissolved dyes or finely dispersed pigments. Dye inks give a wide gamut and vivid colour at low cost, but most fade quickly in light and in ozone-bearing air and can bleed in humid conditions; pigment inks cost more but are far more durable, which is why inks sold as archival are usually pigment-based. Solvent and UV-curable inkjet inks for signs and vinyl almost always use pigments for fade resistance. Because the dye is inside the paper coating and the pigment tends to sit on top, the two also differ in gloss, rub resistance and how they look under raking light.
A colour print is built from at least three colourants, often more. The Image Permanence Institute separates two kinds of change. In overall fade all colourants lose density at a similar rate and the image simply gets lighter, which viewers often tolerate for some time. In colour shift one colourant fades faster than the others and the whole image takes on a cast — lose magenta and a portrait turns greenish — which is objectionable even when small. Black text printed with a single black ink rarely shifts. The practical rule is that a print's life is set by its least stable colourant, and by humidity, ozone and light at least as much as by age.
| Process | Ink consistency | How ink reaches the substrate | Typical colourant | Permanence note |
|---|---|---|---|---|
| Offset lithography | Viscous paste | Plate → rubber blanket → paper | Pigment | Set by pigment choice; process inks are organic pigments of varied lightfastness |
| Flexography | Fluid (water, solvent or UV-curable) | Anilox roller → raised plate → substrate | Pigment | Common on packaging; not designed for long display |
| Aqueous dye inkjet | Thin liquid | Droplets absorbed into the coating | Dissolved dye | Fades in light and ozone; bleeds in humidity |
| Aqueous pigment inkjet | Thin dispersion | Droplets; particles largely on the surface | Pigment | Much more durable; used for archival prints |
| Solvent / UV inkjet | Thin liquid | Droplets onto vinyl and other films | Pigment | Chosen for outdoor fade resistance |
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.
FactModerate evidence
Most dye-based aqueous inkjet inks fade rapidly when exposed to light or ozone, whereas pigment-based inks provide much better long-term durability, which is why 'archival' inks are usually pigment-based.
Source: Inkjet printing
FactStrong evidence
Bleed of inkjet prints is caused by high humidity or water and accelerated by heat; dye inkjet prints are most susceptible, pigment inks much less prone, and electrophotographic prints do not bleed.
FactStrong evidence
When one colourant in a print fades faster than the others, the image shifts in hue — for example loss of magenta gives a greenish cast — and such colour shift is more objectionable than uniform fading.
FactModerate evidence
Flexography meters ink with an anilox roller covered in small cells and a doctor blade that removes excess ink before it reaches the raised printing plate.
Source: Flexography
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.