This 16th-century Netherlandish triptych, a “painting with doors” [1], is intended as a devotional altarpiece; the three panel paintings are adorned with a religious narrative to inspire those who consumed it. This specific altarpiece depicts three common scenes in Christian art (Fig. 1): The Adoration of the Magi, showing The Three Kings bestow gifts following the birth of Christ (Fig. 2); The Rest on the Flight into Egypt, illustrating the Holy Family in a brief moment of respite on their journey while escaping the Massacre of the Innocents (Fig.3); and The Annunciation, where we see the Angel Gabriel revealing Christ’s conception to the Virgin Mary (Fig.4). Traditionally, the doors are interpreted as a boundary between the sacred realm and the viewer. The doors would typically be opened or closed depending on both the time of worship and liturgical time of year; thus, the reverse of doors were often painted with an alternate scene to accompany the central narratives inside. The outer doors may reference the patron saints after which a Church was named, including landscape or sculptural elements. The shape of the triptych’s framework– the engaged frame– presents the triptych as an architectural structure, mimicking grand cathedrals as a place of worship. The triptych’s overall ease of portability suggests that this particular altarpiece was likely commissioned for private devotion, suiting a small chapel in a wealthy household or modest Church.

Vulnerable paint had to be stabilized before the unpacking of overpaint layers could occur. Though it may seem counterproductive to re-consolidate the overpainted surfaces, there would be no safe way to remove the black paint and imitation gilding without loss to the original paint film; otherwise a potential forfeiture of both original media and unwanted overpaint would incur unless the black paint was stabilized prior to removal. To prevent further absorption of wax into the triptych’s support, the wax layers were safely reduced on the surface by applying xylenes with cotton swabs or delicately minimizing it with a scalpel. Once the wax was sufficiently reduced, new consolidation was carried out with diluted BEVA® 371 solution on both the outer doors and inside panels. This adhesive, a thermoplastic ethylene-vinyl acetate (EVA) formulated for art conservation, was chosen due to its success in applications where wax has previously been impregnated into the structure of a painting. To prepare the proprietary adhesive, the BEVA® was diluted with xylenes and heated to flow temperature (around 155 ᐤF). It was then gently wicked into unstable craquelure and paint losses using a fine-tipped brush. The adhesive was kept liquified by continuously heating small amounts on an electric mug warmer, facilitating ease of work flow during the extensive consolidation effort. Pipettes of the diluting solvent (xylenes) were kept close during the process to address instances where the adhesive needed further thinning, or the wicking action was inhibited by wax and flooding the zone with solvent was needed. After the solvents had evaporated out of the BEVA®, any cupped or lifting paint was set down and reattached to the wood substrate with a small heat tool, a WillardⓇ Heated Spatula, utilizing the thermoplastic quality of the adhesive. Stabilized, the triptych was ready to be safely cleaned. The cleaning was approached layer by layer, beginning with removal of surface wax and remaining adhesive residues. As previously done, these were removed using cotton swabs and xylenes; heavy wax deposits were mechanically reduced with a scalpel prior to being wiped away with a solvent swab. The overpainted surfaces were slowly removed on the triptych through various solvent gel actions depending on the layer, targeting the unwanted materials in a controlled manner. Solvent gels are helpful at reducing risk for the conservator and artwork, as far less toxic organic solvent exposure occurs with the relatively small amounts of solvents used in a gel system rather than the heavy amounts of free solvents used with only rolling swabs. Additionally, gels are hygroscopic and facilitate a targeted interaction between the unwanted overpaint, without affecting or minimizing reactions between the chosen solvent and the original paint below. Overall, the solvent gels were also more successful than free solvents at removing the overpaint because of the extended period the gelled solvents spent in contact– therefore solubilizing– unwanted materials on the surface of the triptych. Black overpaint on the outer panels was pursued first. The uppermost layer of black paint was picked up using a solution composed of a polymeric gel (Carbopol® 934), emulsifying agent (Ethomeen® C25), and solvent mixture (80:20 ethanol to xylenes and a small component of water). It was discovered that by applying the gel over a square of thin Japanese tissue and placing a slightly larger square of polyester film (Mylar®) overtop, the uppermost layer of black paint bonded with the entire package after several minutes and could be “peeled” off the surface for disposal. A small amount of free solvents was then used in the appropriate clearance solution to remove any residues of the gel and solubilized overpaint on the surface. The spent gel and tissue glob could then be cleaned off and the Mylar® re-used for future sections. Small windows revealing more original paint began to open up, teasingly confirming the presence of fully representational compositions of two saintly figures: one on each panel set against a detailed landscape. After such success on the outer panels, this initial cleaning technique was applied to the black overpaint on areas inside the triptych.

Cleaning began on the inside of the triptych after the composition on the outer doors had been revealed. The discolored varnish coating on the inner panels was kept intact until overpaint removal had been mostly completed on the inner rails, utilizing the protective qualities of a varnish layer by keeping the paintings isolated while cleaning the sight-edge of the frame. The Carbopol®/Ethomeen® gel containing the 80:20 ethanol to ShellSol™ 15 mixture was the most successful at removing the gold and bronze overpaint. Unfortunately, only scattered specks of the original gilding remained intact. However, the bright orange bole, a preparation layer typically unseen and hidden beneath gilding, was nonetheless an exciting reveal. The bole is dotted with various residues of oil paint from when the panel paintings were executed in-frame ( Fig. 19). It was also confirmed that the upper proper left frame member was a replacement piece, as removal of overpaint on this section revealed a different wood grain and did not uncover any original media that was found on all other members (Fig. 20). The deviated orientation of wooden pegs near the frame joints and wonky finishing of the curvature on this member were the first indicators that this was a replaced section, but it certainly appeared to be a very historic repair.

The discolored varnish and retouch on the inner panels was finally removed with ease, especially when compared to the endeavor of removing the black overpaint. A 4:1 ratio of ethanol to ShellSol™ 15 was used on cotton swabs to roll over and pick up the thick and grimy surface coating, safely cleaning the paintings and uncovering their jewel-toned embellishment ( Fig. 22).