Filigrán oltárkereszt restaurálása

Absztrakt

The conservation of a filigree-decorated altar cross

Based on the marks and inscriptions on its base, the filigree-decorated silver altar cross enclosing the Athos carving was made for the Orthodox community of Kecskemét by Ferenc Pasperger, a silversmith from Pest, in 1815. The most essential, most sacred element of the artefact is the wooden cross protected by glass panes on both sides, which is thought to come from one of the mountain monasteries of Athos in Greece.
The artefact became significantly damaged between 1940 and 1986: three filigree decorations and a glass pane have been lost. After the damage, interventions were carried out on the artefact, presumably to improve its symmetry. It has been an important part of the exhibition of the Hungarian Orthodox Church Museum in Miskolc since 1986; it had been cleaned and coated by the conservators of the Herman Ottó Museum before putting it on display. UV-luminescent photographs of the aged protective coating were taken in UV-luminescent light and its composition was identified via required pyrolysis-gas chromatography-mass spectrometry (Py-GC-MS). The fineness of the silver components was determined using a portable X-ray fluorescence (pXRF) spectrometer.
The conservation process required disassembling the artefact for a better access to each part, which was safely carried out by removing the nut on the shaft and opening the silver mount holding the carving. The intricate patterns of the wooden cross were cleaned under stereomicroscope using an insect pin. The protective coating on the filigree surfaces could be removed with an ultrasonic cleaner filled with acetone. Model experiments confirmed an acidic thiourea solution treatment to be the most effective for removing the sulfide corrosion products from the silver surfaces.
Replacing the decorative elements missing from the top was ethically problematic because the analysis of available analogies has revealed that the elements adorning the top and side parts of similar artefacts often differ. Solder remnants discovered upon disassembling the artefact have revealed that originally the uppermost element was tied to the side of the cross. The structure of the missing filigree decorations could be inferred from the symmetrical construction of the cross. The three supplements, crafted using
silversmithing techniques from 999‰ fine silver, were patinated to match the colour of the artefact, and were fastened on the cross with two-component epoxy adhesive coloured with pigments. The surface protection of the silver was ensured by coating them in a
blend of Paraloid B72 and poly(vinyl acetate) dissolved in acetone-toluene-xylene mixture, a recipe refined through targeted model experiments. A replica for the missing glass pane was crafted by a glassworking master.