The Stain Library

Material

Book pages

A block of paper that dries unevenly and grows mould in the middle, so the method is standing it open, interleaving and turning it.

  • SurfacePorous
  • WashingNo water
  • Colour run riskHigh
  • Reviewed7 September 2026

What book pages can and cannot take

  • Heat Avoid
  • Water and soaking Avoid
  • Acids, including vinegar Avoid
  • Strong alkalis Avoid
  • Solvents Avoid
  • Chlorine bleach Avoid
  • Abrasives Avoid

Always test on a hidden area first and let it dry before you treat the visible mark.

General rules for book pages

A book is a block of paper that dries from the outside in, and the middle is where mould starts.

Stand it on edge, fan the pages open, and interleave absorbent paper every twenty or thirty pages rather than between every leaf, which distorts the spine.

Change the interleaving as it dampens and turn the book over regularly. Expect cockling. A wavy but sound book is a good outcome and pressing it flat while damp is not the way to get one.

Check the label

The archival method for a wet book is to stand it open on its edge with absorbent interleaving placed intermittently through the text block, extending beyond the edges, replacing the interleaving as it absorbs and turning the volume regularly so it dries evenly.

Stains on book pages

A book is many sheets of paper bound at one edge, which makes drying it a different problem from drying a single sheet.

The text block traps moisture

The outside dries first and the centre last, and the centre is where mould begins. That is why archives interleave rather than simply standing a book up.

Interleaving has to be changed

Absorbent paper placed through the text block draws moisture out, and once it is damp it stops working and starts holding moisture against the pages instead.

The spine distorts

Too much interleaving swells the text block and breaks the spine. Intermittent placement, every twenty or thirty pages, is the compromise archives describe.

Cockling is normal

Paper that has been wet dries wavy. Flattening under a weight once it is fully dry recovers some of that; pressing it while damp glues the pages together.

Similar materials

Sources

What we checked and when. Where a manufacturer instruction disagrees with anything here, follow the manufacturer.

  1. Emergency salvage of flood damaged family papers, US National Archives authority

    National archive guidance that paper is very fragile when wet and must be handled carefully, that wet material is air dried on absorbent blotting material with fans circulating air but not blowing directly onto it, that books are stood open on edge with interleaving replaced as it absorbs moisture, that material which cannot be dried within two days should be frozen to stop mould, and that photographic print surfaces must not be touched.

    Checked 7 September 2026

  2. Surface cleaning of paper, Northeast Document Conservation Center authority

    Conservation centre guidance on dry surface cleaning of paper, establishing that surface cleaning is a mechanical dry process using soft brushes and erasers rather than liquids, that it is carried out with the object supported and worked from the centre outwards, and that it can abrade or skin weak paper and media, so friable, coated and damaged surfaces are left to a conservator.

    Checked 7 September 2026

  3. Water damaged photo restoration, EverPresent specialist

    Photo restoration specialist advising that photographs which have stuck together and partly dried should not be pulled apart because the result can be disastrous, that prints are dried on absorbent material away from wind, pets and direct sunlight with the material replaced as it loads up, that blotting the surface risks harming the emulsion, that freezing stops the damage worsening and prevents mould, and that a digital copy is the reliable way to preserve the image.

    Checked 7 September 2026