Testing methods for coating reduction
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Furniture Fragment, 65-3-5
Date: 8th century BCE, Assyrian Period Origin: Nimrud, Iraq Dimensions (cm): 14 H 11 W 6D Materials: elephant ivory, pigment Institution/Owner: Penn Museum Key Treatment Steps
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Summary
This object is part of a group of nine Nimrud ivories in the Penn Museum collection, most of which are documented as furniture inlay. A large collection of comparable carved ivories can be found in the British Museum collection. The object is carved into the shape of a lion paw in the round with a tenon extending from the bottom. The recesses of the diamond pattern have traces of bright red and blue pigment, which appear to alternate in a checkerboard pattern. X-radiography and multi-spectral imaging were completed in 2016 by previous intern Eve Mayberger, and multi-spectral imaging indicated the presence of Egyptian blue pigment.
The top surface of the fragment has small areas with visible Schreger lines. The obtuse angles indicate elephant ivory, which is consistent with the materials available in ancient Assyria.
Condition
The object is mostly complete with minor structural instabilities. The ivory has extensive longitudinal cracking, extending from top surface to paw. The fragment appears to have been previously repaired, and adhesive residues are visible within large cracks. Adhesive staining is also present on the reverse, although it is not visible from the presentation side.
The object has a thick, glossy coating covering all surfaces. Coating creates a plastic appearance and obscures ivory surfaces. Along the obverse face, green textile fibers are intermittently embedded in the coating, likely from a felt or fabric material that was in contact with the object surface. Moderate surface dirt and grime is present, and the majority of it appears to be under the coating.
Treatment
Treatment aimed to reduce the visually inappropriate coating, remove textile fibers, and consolidate vulnerable pigment.
Based on previous treatment reports for comparable Nimrud ivories, acetone and ethanol
were tested for coating reduction. Both acetone and ethanol were found to effectively soften the coating and lift grime. Ethanol was selected for initial coating reduction, and acetone on cotton swabs was used in areas where the coating was particularly thick or resistant. Previous adhesive residues surrounding joins were softened with solvent and reduced mechanically with a wooden skewer. Areas of sandy, granular dirt were left undisturbed. Coating over pigments was left partially intact to avoid excessive mechanical action and pigment displacement. Green fibers were removed along with the coating.
Areas of surface instability were addressed after coating reduction. Isolated areas of fragmented ivory were consolidated with Paraloid B‑72 in acetone. This material was selected for its stability and minimal visual impact. Powdering blue and red pigments were also consolidated with Paraloid B‑72. Consolidant was applied with a hypodermic needle in order to deliver small, controlled amounts. No visible change in sheen was observed after consolidation.
This object is part of a group of nine Nimrud ivories in the Penn Museum collection, most of which are documented as furniture inlay. A large collection of comparable carved ivories can be found in the British Museum collection. The object is carved into the shape of a lion paw in the round with a tenon extending from the bottom. The recesses of the diamond pattern have traces of bright red and blue pigment, which appear to alternate in a checkerboard pattern. X-radiography and multi-spectral imaging were completed in 2016 by previous intern Eve Mayberger, and multi-spectral imaging indicated the presence of Egyptian blue pigment.
The top surface of the fragment has small areas with visible Schreger lines. The obtuse angles indicate elephant ivory, which is consistent with the materials available in ancient Assyria.
Condition
The object is mostly complete with minor structural instabilities. The ivory has extensive longitudinal cracking, extending from top surface to paw. The fragment appears to have been previously repaired, and adhesive residues are visible within large cracks. Adhesive staining is also present on the reverse, although it is not visible from the presentation side.
The object has a thick, glossy coating covering all surfaces. Coating creates a plastic appearance and obscures ivory surfaces. Along the obverse face, green textile fibers are intermittently embedded in the coating, likely from a felt or fabric material that was in contact with the object surface. Moderate surface dirt and grime is present, and the majority of it appears to be under the coating.
Treatment
Treatment aimed to reduce the visually inappropriate coating, remove textile fibers, and consolidate vulnerable pigment.
Based on previous treatment reports for comparable Nimrud ivories, acetone and ethanol
were tested for coating reduction. Both acetone and ethanol were found to effectively soften the coating and lift grime. Ethanol was selected for initial coating reduction, and acetone on cotton swabs was used in areas where the coating was particularly thick or resistant. Previous adhesive residues surrounding joins were softened with solvent and reduced mechanically with a wooden skewer. Areas of sandy, granular dirt were left undisturbed. Coating over pigments was left partially intact to avoid excessive mechanical action and pigment displacement. Green fibers were removed along with the coating.
Areas of surface instability were addressed after coating reduction. Isolated areas of fragmented ivory were consolidated with Paraloid B‑72 in acetone. This material was selected for its stability and minimal visual impact. Powdering blue and red pigments were also consolidated with Paraloid B‑72. Consolidant was applied with a hypodermic needle in order to deliver small, controlled amounts. No visible change in sheen was observed after consolidation.
Treatment Images
During Treatment and Analysis
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