Thinking outside the box

By Sarah Askey

Much to my surprise, the second object that arrived on my bench in the Book Conservation Department was not a book at all, but a nineteenth-century French carriage clock travelling box (fig. 1).

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Fig. 1 French carriage clock travelling box

The Clocks Department (who were taking care of the clock itself) had sent the box over thinking the fragile covering material was paper in need of some TLC. In fact, the box is covered with the thinnest layer of leather, badly faded and acidified. Much of the leather was detached from the wooden substrate, was distorted and split in places, powdery in others (particularly on the 'flesh' side that was meant to be stuck to the box), and had substantial losses. Bits were falling off even as I looked at it.

So, not actually a book, but a three-dimensional object with moving parts and covered with degraded leather, just like an awful lot of books.

The first challenge was nothing to do with treatment, but documentation. Before, after and during treatment, documentation is a valuable part of conservation. It records changes made to the object and is valuable to clients and researchers, as well as reminding conservators where bits have to go back after they've taken them off . . . I took some photos, and began writing a description of the location and length of splits, areas of loss etc., but the damage was too extensive and complex to describe in detail in a way that made sense. Even the photographs didn't fully communicate the box's condition. The solution was damage maps. I sketched some damage maps in pencil, then referred to my sketches to edit my photographs in the microsoft Paint software, to indicate splits and losses in red, abrasions in yellow, and circled the location of white flecks of paint in orange and areas of lifting leather in blue. I also took photographs in raking light to record the three-dimensional distortion in the leather (figs. 2-5).

Fig. 2 Unedited documentation photo
Fig. 3 Splits and losses indicated in red, surface abrasion in yellow
Fig. 4 Detached areas of leather circled in blue
Fig. 5 Photo taken in raking light to show distortion in the leather

The second problem-solving exercise was surface cleaning. The box's exterior surfaces were easily (albeit carefully) cleaned with a smoke sponge and soft goat hair brush. I removed the paint speckles by 'pinging' (a bona fide technical term) them off with a needle tip. The dusty velvet lining and slots for the slide-up front panel and winding key presented more of a challenge (fig. 6).

Fig. 6 Box interior, showing slots between velvet lining and wooden sides for slide-up front panel and winding key

We had a museum vacuum, but the nozzle was too large and cumbersome to get into the corners of the box or down the slots. My tutor suggested I could improvise a smaller nozzle with a plastic pipette. Trimming off the end of a pipette bulb, folding a piece of Melinex® (clear polyester film) around the pipette and vacuum nozzle as an adaptor, and wrapping the whole lot together with masking tape produced a perfectly serviceable, low-tech solution (figs. 7-8).

Fig. 7 Improvised nozzle made from a pipette and Melinex...
Fig. 8 …and masking tape!

The third and most laborious trial was actually sticking the lifting leather back into place. First, I applied Klucel® G (hydroxypropyl cellulose) in isopropanol with a brush to all exterior leather surfaces and as much of the peeling underside as I could access. Klucel G helped to consolidate the powderiness and provide a more stable surface for re-adhesion. After letting this dry, I had to find a way of applying the adhesive. The adhesive I used was a 1:1 mixture of LascauxTM 498 HV and LascauxTM 360 HV. The trouble with leather, particularly deteriorated leather, is that it easily discolours when wet. Compared to the other adhesives in the Books Department, including wheat starch paste and EVA (ethylene vinyl acetate), the acrylic Lascaux adhesives presented the 'least wet' option. I performed a spot test, and dabbed a tiny amount of Lascaux with the tip of a brush on the underside of the leather in an unobtrusive area. As this didn't cause any discolouration, I then brushed on a larger amount of adhesive to peeling leather on the lid. The distorted leather didn't want to lay back down against the substrate, so I held it in place until the adhesive began to set. Unfortunately, the extra moisture and pressure made the leather discolour to a dark pinkish splodge right where my finger had been (figs. 9-10).

Fig. 9 Right side of box lid before treatment
Fig. 10 Right side of box lid after treatment, showing discolouration to the right of the vertical burnished line

Lesson learnt: I had to find a different application method. I tried wiping a very thin film of Lascaux onto a spatula blade, allowed this to air-dry a few moments, then wiped it onto the underside of the leather and held the leather gently in place with my Teflon folder until the adhesive began to set. This drier application method reduced discolouration, but also presented new problems. It was easy enough to apply adhesive to the edges of losses this way, but the spatula blade and shaft were too rigid and too bulky to slide deep underneath large areas of detached leather without lifting the brittle leather and causing new splits. My tutor suggested applying the Lascuax on strips of Melinex. Once again, I was surprised by how 'low-tech' but nonetheless effective this solution was. As with the spatula, I wiped a thin film of adhesive onto a Melinex strip, let this air-dry a few moments, then slid it under the leather (fig. 11).

Fig. 11 Applying adhesive on Melinex strips, with a Melinex barrier layer to protect the exterior leather surface

The thin and flexible polyester film allowed me to access deep into areas of detached leather without causing new tears, and could be trimmed to different widths as required. But even this wasn't a perfect solution, as the edges of the polyester film tended to 'saw' at the friable edges of the leather. In addition, some patches of leather, particularly along the edges of losses, were more fragile than others, and stuck to the Melinex if I applied the adhesive slightly too dry, and darkened if I applied it slightly too wet. Working slowly and carefully, and continually reassessing the leather and how I was using my materials was the only way of managing this. A mere 12 hours and 31 minutes later (11 hours and 11 minutes longer than I had estimated!) the leather was finally re-adhered (figs. 12-14).

Fig. 12a Detail before treatment
Fig. 12b Detail after treatment
Fig. 13 Right side of box after treatment
Fig. 14 Front of box after treatment

Working on the carriage clock travelling box gave me plenty of time to think (17 hours and 13 minutes in total). This project not only challenged my problem-solving ability and practical skills, but also many of my preconceptions about conservation. Before I started studying at West Dean it hadn't occurred to me how readily a book conservator's skills can apply to a range of non-book items. I also wasn't prepared for how creative and vigilant conservators have to be. As each object is different, there's no such thing as 'standard' treatment. Even re-adhering the leather on one small box, I had to continually adjust my use of tools and materials depending on how fragile the leather was or how difficult it was to access. I had also previously thought that conservation equipment would be a bit more 'high-tech', but this project has shown me that the simplest, most useful (and certainly most cost-effective) solution can be plain old polyester film, a roll of masking tape, and a little thinking outside the box.

Fig. 15 Conserved clock and case reunited.