Conservation advice for the public

Conservator supporting a book in a wooden vice.

Do you want to know how best to look after your books, photographs or newspapers? Then take a look at our most frequently asked questions from the public. You'll also find out how to make a time capsule and commission a conservator.

How should I store books?

Generally books and documents need a steady temperature, ideally between 16º - 19ºc, although this might be difficult to achieve in the home. A compromise of 19º-21ºc would be sufficient. Relative humidity should also be as stable as possible. If you can measure relative humidity between 45% - 55% relative humidity (RH) is recommended. Avoid storing books or documents in areas where you find extreme temperature and humidity levels or areas which fluctuate between extremes in temperature and humidity. For example, attics or basements, above radiators and under plumbing where water leakages are possible.

Store books out of direct sunlight and where air can circulate freely. Avoid putting them near windows and placing shelves against outside walls, which can cause condensation and temperature changes.

Use archival boxes (acid free) made to fit and protect valuable and/or damaged books.

Store books on flat, smooth shelves, strong enough to support their weight. Ideally, books should not come into contact with unsealed wood which can release organic acidic vapours. Line shelves with acid free board to avoid this problem. Stand books vertically close together and if possible by size. Use bookends to prevent books collapsing.

How should I store photographs?

Photographs should be stored between 14º-16ºC (68ºF) and a relative humidity between 30-40% RH, ideally. At least the temperature and relative humidity should be consistent. Humidity above 60% speeds deterioration while very low humidity can cause prints to crack, peel or curl. Storage at lower temperatures is particularly advised for contemporary colour prints.

Avoid exposure to anything containing sulphur dioxide, fresh paint fumes, plywood, cardboard and fumes from cleaning supplies. Photographs should be stored in proper enclosures of an archival quality e.g. plastic or paper materials, which are free from sulphur, acids and peroxides. If the relative humidity cannot be controlled consistently below 80%, plastic enclosures should not be used because photographs may stick to the surface of the plastic.

In particular, avoid acidic paper envelopes and polyvinyl chloride (PVC) plastic, rubber bands, paper clips, and poor-quality adhesives such as pressure sensitive tapes. Buffered enclosures are preferred for deteriorated photographic prints on poor-quality mounts.

Avoid the cheap, readily available photo albums, especially those with sticky adhesive pages. In general only use materials which are of archival quality.

How should I store newspaper clippings?

Newspapers are made from low quality wood fibre pulp, which will rapidly become brittle and darken, especially when exposed to light. The deterioration can be slowed down by chemical treatment, but these often darken and deteriorate the paper in themselves anyway.

Deteriorated newspaper should not be stored near photographic materials or other paper materials unless they are protected by acid free archival tissue or protective boxing of some sort.

Correct storage will prolong the life of newspapers:

  • Place clippings in a polyester film folder with a sheet of alkaline buffered paper behind them
  • Put polyester folders in file folders and boxes of high-quality (archival) acid free alkaline buffered materials; store in cool, dry and dark conditions.

If you cannot store the clippings as advised, or if they are already too badly damaged, you can save the information by photocopying the clippings onto acid-free paper.

How do I make a time capsule?


The container must be strong and airtight to prevent the entry of moisture, dirt and insects. The container should be non-corrodable. By far the best modern material for burial is stainless steel which is relatively cheap, easily fabricated and stable in adverse conditions. The capsule should be welded shut (difficult to open but will provide an excellent seal if the welding is done well). Lead-tin solder should not be used as it will deteriorate in the ground, allowing water into the capsule. Screw on caps can be used as opposed to welding or alternatively wing nuts can be used to clamp the lid in place. However, screw threads can 'seize' when left under pressure for a long time, making them difficult to unscrew.

Bottles made of stable glass may survive very well, but are prone to being broken due to shifting foundations, frost or carelessness at the time of retrieval.

The use of plastic containers is open to debate. Not much is known about the long term stability of most plastics under burial conditions and it is possible that they may crack under extreme conditions and the seals may also be prone to wear. Large diameter high density polythene pipes have been used. The end caps can be heat sealed or threaded caps sealed with Teflon tape. PVC (polyvinyl chloride) pipe should not be used for time capsules as it will eventually deteriorate and release acid affecting the contents of the capsule. Before burying, the capsule should be wrapped in a waterproof membrane.

Interior of the capsule

Prior to sealing the capsule it should be packed with a 2.5”-3” layer of ceramic wool fibre, completely surrounding the documents, to protect them from the heat of welding. The environment inside the time capsule should be dry and oxygen free. After welding, oxygen should be removed by flushing the capsule with dry nitrogen through a small hole left for the purpose. The nitrogen will displace the oxygen in the container. The hole should be sealed rapidly. Silica gel or another humidity control system will help control the humidity in the capsule.

Contents of the capsule

Non-paper objects

  • Objects which can decompose and thus give off corrosive substances should be avoided. This includes all plant, animal and insect specimens and anything containing batteries.
  • Polyvinyl acetate (PVAC) or polyvinyl chloride (PVC) will release acid as they age and should be included only with extreme caution. Objects should be wrapped in acid accepting paper, buffered acid-free tissue or washed cotton. These materials will absorb acid.
  • Rubber also deteriorates over time, releasing sulphur. Materials made of rubber should not be used in capsules.
    Textiles should be clean and insect free. Most textiles survive well in a nitrogen environment.
  • All wood, especially oak, gives off acid. It should be kept away from any electronic or metal items before they are inserted into the capsule.
  • Metal items should be free of visible corrosion and in sound physical condition. Avoid polishing items before they are inserted into the capsule.
  • Electronic devices should have their batteries removed and discarded. Leave instructions on the voltage and current requirements of the device. Solar powered devices are a useful alternative. Paper instruction manuals should be stored away from anything electronic.
  • Use archival quality audio and video tape. Bear in mind that the equipment necessary to play back these items may not exist when the capsule is opened.


  • Permanent paper (i.e. paper of an archival quality) should be used. If permanent paper is not used, all documents should be deacidified to help prevent chemical degradation. A professional paper conservator should be employed to do this.
  • Newsprint is destroyed rapidly by acid residues left in the paper from the manufacturing process. Newspapers must be deacidified.
  • If hand written, archival record ink, not biro, should be used.
  • Before being placed in the container, the documents should be dried so as to reduce the relative humidity to 30%.
  • Each artefact or set of documents should be placed in an inert polyester bag prior to insertion into the capsule. This will ensure that dissimilar materials are isolated from one another.


  • Black and white photographs should be used in preference to colour material.
  • All colour photographic material has a relatively short life and may be in danger of darkening or fading. Polaroid photographs should not be used even in short life capsules due to their instability.

Burying the time capsule

Place the capsule in a cool, dry location, where it will not be exposed to great fluctuations in temperature. Time capsules are most commonly found buried below ground level in the foundations of buildings. A drained concrete or brick vault lined with fibreglass should be built in order to minimise temperature fluctuations and prevent access of water. The site of a time capsule is often marked in some way. The International Time Capsule Society exists to maintain a register of all known time capsules, to promote research into the history, variety and motivation of time capsule projects, to educate and raise awareness of time capsules among the public and scholarly community and to act as a clearing house for information about time capsules.

Should I use leather dressings on my books?

Leather dressings were at one time thought to be useful in extending the life of leather bindings, but experience has shown it only to be cosmetic. Leather dressing should only really be applied by someone with professional expertise on new and non-decayed leathers, in good condition, otherwise it is likely to cause more harm than good.

Research has shown that leather dressings can cause leather to dry out over time, leading to stiffness and darkening or staining of the surface.

If too much is applied too frequently, the surface becomes sticky, attracting dust. It can migrate to the text block, staining and deteriorating the paper. One of the biggest problems is that in the past leather dressings have been used too much.

If a leather book has become stiffened through the use of leather dressing, proper handling techniques and support of the book structure will help to ameliorate the problem.

If you want to use a leather dressing try to avoid those containing a solvent.

For protective handling purposes polyester film dust jackets can be made to help prevent dry rotted leather from offsetting onto adjacent books and from further deterioration.

Consolidants can be applied by a professional conservator to bind dry rotted leather.

Red rot is not contagious. It is not a fungus but a chemical breakdown of the proteins in the leather so that they eventually crumble.

How do I find and commission a conservator?

To find a conservator, search the Conservation Register, which holds detailed information on conservation-restoration practices in the UK and Ireland and is operated by the Institute of Conservation in association with English Heritage.

Commissioning conservation work, whether for a single item or for a collection, requires negotiation to reach a contractual agreement. It is therefore vital that both parties provide and share all necessary information. An introduction to the commissioning process can be found on the Conservation Register website.

The conservator will need information about the item or collection in order to assess the type and degree of treatment required. The following are some examples:

  • its history and context within the collection and relationship with other copies held in the institution or elsewhere
  • the level and kind of use it will experience
  • whether a surrogate exists (a microfilm, facsimile, digital copy or preservation photocopy) or whether it is planned to create one, and if so, the physical implications of the surrogating process
  • details of previous treatments, especially the use of chemicals and materials - which may have health and safety implications
  • details of funding arrangements including any deadlines to be met
  • any proposed changes of use or storage or proposal to exhibit the item or lend for exhibition elsewhere
  • the institution's preservation policy should include principles such as a requirement for minimum intervention in original structures or the creation of robust structures for open-access collections, and the policy should be made available to the conservator.

The institution, or the owner of the material, should be able to undertake or commission a degree of quality assurance on the work done.

Blog posts

Conservation of Maps in the digitisation project: Qatar Foundation Partnership – Part 1

Friday, December 16, 2022

The British Library Qatar Foundation Partnership (BLQFP) is a digitisation project that began in 2012 to create the Qatar Digital Library (QDL). For over ten years this free bilingual online portal has been fed from the British Library´s collections related...

Textiles in Ethiopian Manuscripts at the British Library

Friday, December 17, 2021

Eyob Derillo, Curator Ethiopic and Ethiopian Collections. Little is known about the secrets that Ethiopian Christian manuscripts retain inside their covers. In addition to the texts that cover the full range of topics, from religion to magic, or from poetry...

Conservation of the Granville Archive papers

Friday, December 10, 2021

Veronica Zoppi, Conservator General description: The Granville Archive, recently acquired by the British Library, includes a vast collection of letters and papers relating to British national life in the 18th and 19th centuries. These papers had been unknown to researchers...

Important information for email subscribers

Friday, August 13, 2021

Unfortunately, the third-party platform that the British Library uses for email notifications for our blogs is making changes to its infrastructure. This means that from mid-August 2021 it will no longer send notifications by email to subscribers. To find out...

More blog posts