Due to their stability, reversibility, and working properties, Lascaux 360HV and 498HV adhesives are becoming increasingly popular in book and paper conservation. Samantha Sheesley of the Conservation Center for Art and Historic Artifacts presented three case studies of treatment applications that take advantage these properties.
The first case study involved treatment of a set of “Sailor Jerry” drawings on transparent paper. Both the presence of water-sensitive media and the reactive nature of the transparent paper meant that Sheesley was looking for a way to mend the drawings without introducing moisture. Lascaux 498HV was brushed in an even film layer onto a sheet of silicone-coated polyester and then quickly dried with a hair drier. Sheesley pointed out that this quick drying is an important step in order to prevent dust from settling into still-tacky adhesive. After drying, a sheet of tengucho mending tissue was placed on top of the 498HV film layer; the adhesive was reactivated with an iron to adhere the paper to the film. After removing the silicone-coated polyester, the adhesive-coated tengucho was used to create mending strips that were applied to the drawings with heat, resulting in nearly-invisible mends that are easily reversed with either heat or solvent (acetone or toluene).
The second treatment example of was the re-lining of a lithographic poster. A hydrophobic coating on the paper and water-sensitive media required a dry lining method. Lascaux 498HV was applied to a sheet of silicone-coated polyester (a light mist of water under the polyester secured it to the bench) and squeegeed in multiple directions to create a thin, even film – Sheesley emphasized again that it was important to work quickly when applying and drying the film layer in order to avoid dust settling in the adhesive. Lining paper was placed on top of the dry adhesive film and adhered with an iron. Once cooled, the silicone-coated polyester was pulled away from the lining paper. The poster was placed face down on a suction table to keep all pieces in place and then the lining paper was dropped adhesive side down, tacked in place with an iron, removed from suction table and ironed overall.
The third case study – in my opinion, the most ingenious of the applications – involved the use of a Lascaux mixture as a fill material for a convex photo button with a severe horizontal split. The button was a silver gelatin print with a cellulose nitrate coating on a metal substrate. The tented split created a gap that was both structurally and aesthetically problematic. Sheesley needed a fill material that would be flexible enough to accommodate dimensional changes in the object. She mixed equal parts Lascaux 360HV and 498HV, in order to take advantage of the unique properties of each, and added pigment. As in the first two examples, this mixture was brushed onto silicone-coated polyester and quickly dried. She scored the edge of the pigmented film and removed a small strip which she then rolled into a coil – the inclusion of Lascaux 360HV in the mixture, which retains it’s tackiness even when dry, meant that there was just enough residual tackiness for the adhesive film to stick to itself. After mending the photo with small strips of Beva (which were inserted in to the crack with very fine-point tweezers) the Lascaux coil was fitted into the gap and tacked in place with an iron. Sheesley then ironed the coil overall through a sheet of silicone film which imparted a shiny texture to the surface of the Lascaux fill, mimicking the surface quality of the cellulose nitrate for better visual integration. The fill was then inpainted with acrylics. The “after treatment” photos of the button were impressive – I hope an appropriate object comes across my bench soon so that I can try out this technique!
Q: Does creating repair tissue using dry adhesive rather than wet adhesive (i.e., brushing diluted Lascaux onto mending tissue) create a less transparent mend?
A: Sheesley tested both methods and found then to be similarly transparent. She also speculated that the the dry film methods would be more easily reversible, since the adhesive doesn’t penetrate into the mending paper fibers as it would in a wet application.
Q: Were any adverse effects of using the hot iron next to the cellulose nitrate?
A: No harmful effects were observed.
Q: Was there any residual tackiness on the coil infill, since it contained 360HV?
A: No, the presence of 498HV in the mixture and the acrylic paints on top of the fill meant that there was no remaining tackiness.
Q: Concerns about reversibility.
A: Sheesley stated that though reversing the treatments could be time consuming, she was able to reverse all of her repairs.