Tuesday, November 21, 2017

Edible archives: the pest peril!

Hide or Leather Beetle
Today’s theme is edible archives - you’re probably thinking this is a chance to celebrate the history of British gastronomy and share the culinary delights of our city… Well we could certainly offer up a tempting platter old recipes and vintage advertisements, but we decided to look instead at the problem of archives that have quite literally been eaten away!  The very stuff of archives - paper, leather, vellum, hair, cloth, wood and glue - is an excellent source of food for insects and other critters.  Some of the material we’ve received over the years has been riddled with tell-tale holes - often with the offending creature(s) still present.  This is where the work of our Conservator comes in…

Sheffield documents that suffered damage
from fire, water and mice. Now conserved
and safe from further deterioration.
The Conservation Unit, in short, perform miracles when it comes to documents that have had a hard life and are fast perishing.  From wax seal repair to the delicate treatment of ancient manuscripts, the Conservator and Preservation Assistant work in a meticulous and precise manner to ensure the continued preservation of our unique documents for many years to come.

Brown House Moth
One of their main tasks is to inspect all incoming archive material for potential problems.  People have a habit of storing old papers in damp cellars and draughty garages - fertile breeding grounds for beetles, silverfish, mice and woodlice.  Each year we receive around 1,000 boxes of new material into the archives; as soon as it comes through the door it needs to be isolated immediately.  The Conservator checks for evidence of insect invasions: tell-tale signs include holes in paper, tunnels bored in wooden frames, frass (small piles of fine, dry, powdery insect excrement) and exuviae (shed skins of insect larvae that have pupated).  Insects are particularly drawn to the cellulose and starch (plant sugars) and collagen and keratin (animal protein) in archive materials.  Arresting potential problems quickly is key: the staving off of the insect’s oxygen source, the use of pheromone traps and occasionally deep-freezing (using a specialist off-site company) are all tools the Conservator can employ.  It is crucial that any insect issues are dealt with in an isolated area to ensure an infestation does not occur in the main strongroom.

The humidity of an environment can play a critical role in the survival of insects.  The strongroom at Shoreham Street has state-of-the-art environmental controls (which conform strictly to British Standard PD5454 2012) and fluctuations in humidity are carefully monitored on a daily basis by our Preservation Assistant.  Achieving a stable environment is a finely balanced act and a swing either way (in terms of temperature or humidity) can give rise to problems which pose a threat to the stability of the documents.  If the environment is humid above 65% relative humidity (rh) mould and insects are likely to be active.

A completed treatment on a 300-year old volume.
Once stabilisation has occurred, the Conservator examines any documents that have started to be eaten away.  In some cases rescue is impossible: a mouse can make quick work of a box of paper.  More often, though, we find that insect attacks and woodworm invasions can be arrested reasonably successfully.  Where paper has begun to disintegrate, the Conservator will stabilise it using a combination of conservation tissues and Japanese infill papers to replace the missing pieces and strengthen the structure of the item.  Our aim is to make documents robust enough to handle again whether by conservation treatment or preservation packaging (or both).

Evidence of woodworm in the wooden cover of the
Beauchief Cartulary which dates from the 1400s.

If you’re storing your own precious family papers in a precarious location at home, it might be worth checking to make sure they’re safe.  Deeds, old photographs, personal letters, war memorabilia and so on are irreplaceable.  If you need any advice on these matters from our Conservator, please get in touch: Conservation.Library@Sheffield.gov.uk  We also offer a bespoke Conservation service should you have any documents or books that require repair.  Again, please contact us for details.

In the meantime, keep your eye out for the pesky critters (pictured) and take a look at some of the archives in Sheffield that survived attack and lived to tell the tale…

Tomorrow we’ll be taking a look at the world of ‘Hairy Archives’ (#Hairyarchives) and all things hair-related!