Why old paper and photographs deteriorate

Understanding the enemies of your archive makes every other decision easier. Light is the most relentless: ultraviolet fades inks and handwriting, and a few weeks on a sunny windowsill can bleach a postcard beyond reading. Damp is the second. Mould spores are always in household air, and once relative humidity climbs above about 65 per cent they germinate, leaving the grey speckling and purple-brown “foxing” that stains paper. Heat speeds up every chemical reaction in paper and photographic emulsion.

Then there are the familiar villains: Sellotape that has yellowed and gone brittle, rubber bands that have hardened into the paper, PVC sleeves sweating onto a photograph, and the lignin in cheap mount board and newspaper clippings. Add silverfish, clothes moths and the occasional mouse, and the case for careful storage is overwhelming.

Handling fragile items safely

Most damage is done in the five minutes someone decides to “just have a quick look”.

• Clear a table and cover it with clean blotting paper or acid-free tissue. Work in good light, with no food or drink nearby.
• Wash and dry your hands thoroughly. Hand cream, sunscreen and sanitiser residue all transfer to paper.
• Wear close-fitting nitrile gloves for negatives, glass plates and metal objects. For prints and documents, clean dry hands are usually safer than cotton, which catches on torn edges, though cotton is the right choice for textiles.
• Slide a sheet of stiff card under a document and lift that, never a single corner. Support large maps and certificates flat with both hands.
• Never repair with Sellotape, glue or laminating pouches. Put loose fragments in a small paper envelope and keep it with the parent item.
• Remove rubber bands, paperclips and rusty staples, replacing them with unbleached cotton tape. If you must mark something, use a soft pencil on a separate slip rather than on the original.

Storing a collection at home

The best place to keep an archive is a cool, dry, dark room with steady conditions: roughly 18 to 20 degrees Celsius and 45 to 55 per cent relative humidity. In practice that means a spare bedroom or an interior cupboard — never a loft, garage, cellar, conservatory, or the top of a wardrobe beside a radiator or hot-water pipe.

• Use acid-free, pH-neutral boxes and folders, described as archival or conservation grade.
• Store documents flat where possible. Large items may stand vertically if the folder supports them properly and the box is not packed tight.
• Keep photographs upright and interleaved with acid-free paper, in polyester or polyethylene sleeves rather than PVC.
• Avoid old self-adhesive “magnetic” albums. Choose acid-free pages with photo corners or slip-in polyester pockets.
• Label boxes on the outside in pencil or archival pen, noting contents and the date you packed them.
• Check everything once a year. If you find mould, isolate the item in a sealed bag and do not brush it off indoors.

Photographs, negatives and slides

Photographs need slightly different care from paper. Keep negatives and slides separate from prints, because the two materials release different chemicals as they age. Store negatives and slides vertically in acid-free enclosures, handle them only by the edges and never touch the emulsion. Glossy prints made before about 1960 scratch easily, so work over a clean surface with the image face up.

Resist the urge to write names on the back of a photograph in ink; it bleeds through. Write on the sleeve instead, or use a soft pencil along the very edge of the reverse. Slides and glass negatives that are cracked, sticky or smell of vinegar are best left to a conservator.

Digitising without causing harm

Digitising is no substitute for good storage, but it is the best way to share a collection without wearing it out.

• A flatbed scanner suits documents and prints. Scan text at 600 dots per inch, small or damaged prints at 1200, and slides or negatives at 2400 to 4800 using the correct holder.
• Never feed old paper through a sheet-feeding scanner, and never press a fragile item flat.
• For albums and oversize items, photograph from directly above with the camera on a stand, in soft daylight rather than flash. Use a plain background and check for glare.
• Keep a full-resolution TIFF as the master and make smaller JPEG copies for everyday use. A 24-bit colour scan captures the subtle tones of old photographs.
• Name files so they make sense in twenty years: date, event, names, place. Keep an index of the stories behind the pictures, and record older relatives talking about them while you can.
• Back up properly: three copies, on two kinds of media, with one kept somewhere else.

Sharing, and when to call in a conservator

Once an item is scanned, share the copy and leave the original in its box. Handing a 1920s album round at a family gathering is how corners get torn and pages bent. Low-resolution copies are perfectly good for sending to relatives, and they keep your master files from being copied and re-copied.

Some items are beyond home care: mouldy papers, water-damaged certificates, broken glass negatives or anything genuinely irreplaceable. County record offices, local archives and family history societies often give free initial advice, and a qualified conservator can stabilise an item rather than restore it. Take photographs of the problem before you do anything, so you have a record of its condition.

A family archive is a living thing, and a short label written today — a name, a date, a place — is worth more to your descendants than any box, however grand.