THE IN SITU TREATMENT OF THE WALLPAPER IN THE STUDY OF THE LONGFELLOW NATIONAL HISTORIC SITE
Thomas K. McClintock
The objectives of the conservation project were to improve the appearance of the wallpaper and to promote its sound physical condition. It was proposed to clean the paper as possible, to repair areas of damage, to reattach areas of detached wallpaper, and to fill and tone areas of loss. After an examination for condition, at no point was anything but an in situ treatment considered.
Loose surface dirt was wiped off with a soft brush. To remove more stubborn grime, bags of eraser powder were rubbed over the surface, but these were quickly torn by abrasion against the rough surface. Where the surface was determined durable enough, cleaning continued with kneaded erasers. These removed the most grime, produced little streaking if used evenly, and left little residue to clean up. This cleaning was the most important factor in the improved appearance that was a result of the entire treatment.
To reattach the paper to the plaster underneath, a 2:1 mixture of wheat starch paste and methyl cellulose (4% solution of the product available from TALAS) was used, diluted to the consistency of heavy cream. This provided the desired tack, optimum working time, and did not cause stains. At tears or where the paper had separated from secure plaster, the wallpaper could be easily reattached by injecting the adhesive behind it and applying pressure with a wad of cotton for several minutes, which also removed any excess adhesive. At areas of delamination without tears, it was necessary to first make a small hole so that the syringe could be slipped behind the brittle paper without shattering it.
Where there was no firm base to which the wallpaper could be readhered, several approaches were taken. Because the paper was so brittle, it was difficult to pull it away where torn to reach fragmented plaster underneath. Since the paper was of a single color and without a pattern, it was impossible to make inconspicuous incisions following areas of design to lift the paper and repair the plaster. Instead, the plaster was consolidated with a chalk/gelatin (4% solution) putty the consistency of mayonnaise, which was injected with a syringe. The paper was pressed lightly against the putty so that it could conform to the back surface of the wallpaper. This filled the gaps and readhered the loose plaster. After the putty dried, the wallpaper was readhered with paste to this more firm base. Wherever possible, tears were mended by slipping pieces of pasted mulberry paper behind them so that the tear was bridged to provide reinforcement.
Because the plaster underneath could not be made completely smooth behind the wallpaper, particularly just below the cornice where there were large gaps behind the paper, the best solution was to reinforce the wallpaper by inserting paper patches. Where there were large draws, it was necessary to make several compromises. If the draws were torn or were slight enough to be pressed flat, they were treated as above. When the draws were larger and not torn, efforts were made initially to relax the paper by injecting a more dilute adhesive behind it. But upon applying gentle pressure to flatten the draws, the paper would still fracture. The paper was then left untreated with the idea that sound paper, if drawn, was preferable to a surface that was broken up and set down. Fortunately, a large bookcase hides the corner where this is most apparent.
Most of the losses were filled with a chalk/gelatin putty as used in painting conservation. Inserts of okawara paper were used in large areas of loss where the plaster had been painted over but remained rough and unsightly. Otherwise, most losses could be filled evenly with putty and sanded smooth. All of the losses were inpainted with Liquitex acrylics. This medium had enough body so that the surface could be textured to simulate that of the painted wallpaper.
The times spent on the project were: 24 hours for surface cleaning, 43 hours for mending and 26 hours for filling and inpainting, totalling 93 hours.