Short answer
Paper's colour starts with its fibre: fully bleached chemical pulp is white, mechanical pulp keeps the wood's lignin and is creamy, and recycled pulp carries residual inks and fibres. Fillers, coatings and dyes adjust it, and optical brighteners make many papers look bluer-white in daylight. Paper yellows and browns as lignin oxidises and as acids — from residual alum sizing or lignin breakdown — hydrolyse the cellulose, faster in light, heat and humidity. The same design therefore looks different on different stocks and changes over time.
Relative to other materials in this section, not a measurement of a particular product.
| Process | What you see | Driven by | Slowing it |
|---|---|---|---|
| Yellowing and browning | Cream to brown, most strongly in wood-pulp papers and at edges | Lignin oxidation and acid hydrolysis of cellulose, accelerated by light and heat | Alkaline, lignin-free papers; dark, cool storage |
Chemical pulping dissolves most of the lignin out of wood, and bleaching removes the rest, leaving nearly pure cellulose that is white and stable — the basis of good writing and art papers. Mechanical pulping grinds wood with its lignin intact, giving high yield and opacity but a creamy or greyish colour that darkens quickly; it is used for newsprint, magazines and some boards. Recycled pulp is de-inked and often bleached, but residual ink specks, mixed fibres and fillers make it greyer or duller, as the recycled-paper page describes. Deliberately tinted papers — cream, ivory, pastel and deep colours — use dyes or pigments added to the pulp, and coloured papers are as prone to light fading as other dyed materials.
Fillers such as calcium carbonate and kaolin add opacity and whiteness. Coated papers carry a layer of pigment and binder that gives a smooth, bright surface on which inks sit up with higher saturation, which is why the same image prints more vividly on coated than uncoated stock. Optical brightening agents absorb ultraviolet and emit blue light, making paper look whiter under daylight but not under UV-free LED or incandescent light. Card and board are built in layers: solid bleached board is white throughout; folding boxboard has a mechanical-pulp middle with bleached outer layers; white-lined chipboard has a recycled grey or brown back with a thin white top, so its white can look greyer where the lining is thin.
Two chemistries age paper. Lignin in mechanical-pulp papers oxidises in light to form yellow compounds, which is why newsprint yellows within days in sun — conservators place such low-quality papers in the most light-sensitive category. Acid hydrolysis breaks cellulose chains; the acid comes from residual alum used in the rosin–alum sizing common from the nineteenth century until alkaline papermaking spread, and from the breakdown of lignin itself. The result is yellowing, then browning and embrittlement, often worst at edges and in spots. Heat, humidity and pollution accelerate both. Alkaline, lignin-free papers with a calcium carbonate buffer resist these changes, which is the basis of archival and 'permanent' paper.
Because paper white is the lightest colour a print can show, and printing inks are transparent, the stock tints every colour in the design: a warm uncoated cream makes blues greener and whites ivory; a bright blue-white coated paper makes everything cleaner and cooler. Uncoated stocks absorb ink and scatter light, so colours print duller and darker, and colour management uses different profiles for coated and uncoated paper. For packaging, the board's surface and back affect both colour and perceived quality. When approving printed colour, proof on the production stock under the lighting where it will be seen, and remember that brightened papers look different under daylight than under warm retail LEDs.
Why: Proof on coated paper, job on uncoated stock.
Fix: Proof on the production stock with the matching profile.
Why: Optical brighteners glow under daylight but not under UV-free retail LEDs.
Fix: Judge under the retail lighting; do not rely on brighteners for whiteness.
Why: Mechanical-pulp paper or acidic mount oxidising, accelerated by light.
Fix: Use lignin-free, buffered mounts and UV-filtering glazing; keep out of sun.
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.
FactStrong evidence
Acid hydrolysis of cellulose shortens its chains, causing loss of strength, yellowing and embrittlement; acidity in paper comes from residual alum used in sizing and from organic acids formed as lignin oxidises in wood-pulp papers.
FactStrong evidence
Yellowing of some low-quality papers such as newsprint is among the most ultraviolet-sensitive forms of light damage identified by conservators.
Source: Agent of deterioration: light, ultraviolet and infrared
FactModerate evidence
Paper degradation is often uneven, with higher acidity at edges and in foxing spots.
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.