Short answer
Recycled paper usually starts from a lower-brightness pulp because some ink, dye and fine dirt survive deinking, and because the recovered paper often contains yellower mechanical-pulp fibres. How white it ends up depends mostly on which recovered-paper grades were used, how thoroughly the pulp was deinked and bleached, and how much white is added back.
Recovered paper is traded in grades — ordinary mixed papers and board, newspapers and magazines, and high grades such as office paper and white cuttings. Each carries different amounts of ink, mechanical-pulp fibre (which still contains lignin and yellows) and coloured paper. A study of two mill deinked pulps for tissue found the one made mainly from high grades at 70% ISO brightness and the one made mainly from ordinary grades at 58%, with the second noticeably yellower (b* about +5 against +2.5) and containing almost twice the lignin. The recycled product's colour ceiling is largely decided the moment the furnish is chosen.
Two recycled sheets can have the same overall brightness and look quite different because one has visible specks. Specks are ink particles, toner, coloured fibres or adhesive fragments that were too large or too firmly bound to be floated or washed out. The industry deinkability scorecard counts dirt area in two particle-size classes separately from luminosity for exactly this reason: a reader perceives a few large specks as dirtiness, while a uniform loss of brightness reads as greyness. Toner from laser printing, varnished inks and some adhesives are common sources of specks that survive.
Paper brightness (ISO 2470-1) is a reflectance measured in the blue at about 457 nm. It was designed to track bleaching, not appearance; the USDA Forest Products Laboratory has long pointed out that it is not necessarily a measure of how the paper looks to the eye. A recycled paper can have acceptable brightness yet still look grey (low overall lightness) or cream (positive b*). Whiteness and CIELAB values are better for describing what a customer will see, and fluorescent brighteners — which raise measured brightness under UV-containing light — complicate comparisons between papers further.
Brown and grey recycled board are usually not deinked at all. Packaging board and the inner plies of folding cartons are made from unbleached recovered fibre because strength, not whiteness, is what they are for. When a white surface is wanted, a thin top ply of bleached virgin or high-grade recycled fibre, or a white mineral coating, covers the grey middle. That is why the cut edge of many white cartons is grey: the colour you print on sits on a white layer only a fraction of a millimetre thick, and a deep scratch or crease reveals the recycled core.
Why: Brightness measures blue reflectance only; overall lightness is lower.
Fix: Compare CIELAB L* and b* or CIE whiteness, not ISO brightness alone.
Why: Toner or adhesive particles that deinking did not remove.
Fix: Choose a stock with a stated dirt specification, or move solids to a coated or high-grade top ply.
Why: The white top ply cracks and reveals the unbleached recycled core.
Fix: Score and crease to the board maker's settings, or choose a board with a heavier white top layer.
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
In one mill's deinked tissue pulps, a furnish mainly of high-grade recovered paper gave 70% ISO brightness and one mainly of ordinary grades gave 58%, with b* of about +2.5 and +5.1 respectively.
Caveat: Two pulps from one mill; other furnishes and processes give other values.
FactStrong evidence
ISO brightness is a diffuse reflectance at around 457 nm and is not necessarily a measure of how paper appears to the eye.
Source: Recycling Bleach Technologies
ConventionModerate evidence
The European deinkability scorecard assesses dirt specks in two size classes separately from luminosity and a*, so a product can fail on specks even when brightness is adequate.
Source: Assessment of Printed Product Recyclability – Deinkability Score (Issue 2)
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.