Heloise Marchbanks's bone folder is the colour of weak tea. It has been hers since she bought it from a bookbinder's supply house in Edinburgh in 2002, when she was a third-year student at the Camberwell School of Art. It cost, at the time, eleven pounds fifty. She has used it almost daily for twenty-four years.
The bone is real bone, taken from cattle leg. It was cut and polished by a small German manufacturer that has been making them since the 1880s. The tool's shape — a flattened spoon about six inches long, tapering at one end and rounded at the other — has not changed in any meaningful way since the eighteenth century.
It is used, in Marchbanks's daily work, for almost everything. Folding paper without bruising the fold. Burnishing wet repairs. Smoothing the edges of inserted tissue. Setting down hinges on a book's textblock. Working creases out of damp paper without the heat of a flat tool. There is, in paper conservation, almost no operation that does not involve a bone folder at some point.
The reason is the bone's particular surface. It is hard enough to apply real pressure but soft enough not to mark. It does not transfer rust, as steel does. It does not absorb moisture, as wood does. It does not conduct heat, as bone-shaped plastic substitutes do, and so does not affect the temperature of damp paper underhand.
It is also, satisfyingly, almost free.
Marchbanks works in a converted Glasgow tenement on the Garnethill side, in a studio she shares with two other conservators. The studio takes work from the National Library of Scotland, from several private collectors, and from the Burrell Collection's reserve archive. The pieces that come through are old, sometimes very old. The 1652 atlas she repaired last autumn. The 1814 estate ledger she is working on now. A small leather-bound 1726 prayer book from a private collection in Inverness, awaiting her attention next week.
Each piece is approached with the same set of tools, and the bone folder is always among them. Marchbanks owns three. The Edinburgh one from 2002, which she uses for general work. A smaller Teflon-coated folder she uses on heavily sized papers that might mark under bone. And a third, of horn rather than bone, that she uses on the most delicate eighteenth-century papers where she wants the absolute minimum of friction.
The Teflon and the horn she bought in 2014, after attending a workshop in Vienna led by a senior conservator at the Albertina who used both interchangeably. The bone, for most work, remains her first choice.
Bone folders are sold by every bookbinding supplier in the trade for between ten and forty pounds. The expensive ones are larger, hand-finished, and signed by individual makers. The cheap ones are machine-cut and rough. The middle ones, costing about fifteen to twenty pounds, are perfectly adequate for almost all work. Marchbanks's, at twelve pounds in 2002 money, would now cost about twenty.
The shape varies slightly between makers. Some are more spoon-like, with a deeper curve. Some are flatter, almost paddle-shaped. Marchbanks prefers a moderate curve, which she finds gives the best combination of versatility and comfort. A flat folder is better for very long straight folds. A deeper curve is better for working into the gutter of a bound book. The middle shape does both adequately.
The tool is used, in essence, with the side rather than the edge. The side burnishes. The edge creases. The rounded tip works into corners. The pointed end, properly handled, can be used to slip a small piece of tissue into a tear without the operator's fingers touching the work.
It is, in this sense, an extension of the hand, with the same range of movement and the same precision, but harder and smoother than skin and bone alone.
The bone folder also has, over a working life, a slow tendency to take on the user's specific patterns of use. Marchbanks's folder is now worn slightly to one side, where her right thumb has rested on it for twenty-four years. The wear is invisible to a stranger and obvious to her. A new folder, borrowed from a colleague, feels wrong in the hand for a minute or two before the hand adjusts.
She has been asked, occasionally, whether the use of bone is troubling on ethical grounds. The bone is a byproduct of the meat industry and is not slaughtered for the purpose. It is, in this respect, no different from the leather used in bookbinding itself. Marchbanks has thought about it and made her peace with the use. Conservators who feel otherwise use horn or Teflon, both of which work nearly as well.
What the bone folder will not be replaced by is any electronic or mechanical tool. There is no powered equivalent. The operation it performs — applying carefully calibrated pressure to a precise spot on a small piece of paper — is by its nature manual. The hand has to feel the paper give way under the burnishing, has to feel the crease set, has to feel the tissue flatten into place.
A machine cannot do this. The hand can do little of it without the bone folder. The combination, hand and tool, is the working unit of the trade.
Marchbanks has taught, occasionally, at the Glasgow School of Art's conservation programme. She tells the students, on the first day, to buy a bone folder before they buy anything else. They almost always do.
Over the years, she has noticed, the students who develop fluency in the tool are usually fluent in the rest of the trade within a year or two. The students who never quite get comfortable with it — who hold it wrong, or apply too much pressure, or never learn the small sideways motion that burnishes a hinge cleanly — generally do not make it through the second year.
The folder is, in this sense, a quiet diagnostic. The hand that can use it well can probably be trained for the rest of the work. The hand that cannot, generally cannot.
Marchbanks does not say this to the students. She does say, on the last day of the course, that the bone folder they bought in September is the cheapest professional tool they will ever own and that they should expect to use it for the rest of their working lives.
Her own folder shows no signs of failing. Bone, properly cared for and not dropped on stone floors, will outlast most other materials in a conservation studio. It does not crack. It does not warp. It does not corrode. It softens slightly, over decades, into the shape of the hand using it.
Marchbanks intends to use hers, she said over a cup of tea on a wet Glasgow afternoon, until one of the two of them gives out.