3 PRELIMINARY TREATMENT OF TRACINGS

AFTER COMPLETION of the initial examination and photographic documentation, the drawings were detached from their mounts by slitting through the top layers of the old wood pulp core mats beneath each gummed paper tab. Separation between tab and mat was considered too risky to the brittle, disintegrating edge of the tracing paper because it involved contact between the edge and the metal spatula. Then the tabs were removed from the tracing paper using methyl cellulose poultices applied with a fine sable brush.11 Excess adhesive remaining on the support was picked up onto slightly damp clean swabs. All areas thus dampened were immediately pressed and left to dry under weights. Folded edges were lightly moistened along the fold lines. When the paper fibers had relaxed sufficiently they were unfolded and immediately pressed until dry.