Karolina Soppa

Hochschule der Künste Bern · Konservierung und Restaurierung

In this study, films of three common materials used in conservation-gelatin, sturgeon glue, and methylcellulose-were evaluated for dimensional change after 10 humid climatic cycles (53% and 75% relative humidity) under low force (0.1 N). Gelatin and methylcellulose formed stable films that expanded by an equal ratio upon humidifica-tion and contrac...

During the process of conserving the painting La Salle des Cariatides au Louvre (1921) by Edouard Vuillard at the Atelier Eysler GmbH, damage was discovered in the form of stiff, fragile, and slightly lifted paint flakes. The heavily concave painting layer could not be flexed either with moisture or heat. The surface of the painting appeared dull,...

full text online: https://www.getty.edu/publications/conserving-canvas/v-adhesives/28/

This case study presents a novel approach to gluing a poorly fitting open joint on a polychromed 16th century lime- wood relief, relying on digital 3D technology. Photogrammetrically generated digital 3D models of the two gluing surfaces allowed in a first step to analyze the conditions in the virtually recreated joint and then to produce a CNC-rou...

Mammalian and cold- as well as warm-water fish gelatins show two different film properties related to the film formation process during drying as well as distinct behaviors under varying climate conditions. The results of our study showed that warm-water fish and mammalian gelatin behave like elastomers, a property that recommends their use as adhe...

Many modern artworks exhibit flaking paint. Rarely restored, they hardly show any stains, so it is important that the absorbent canvas is not penetrated with unnecessary foreign material while re-adhering the paint layer. Such a situation was found with the painting "Cathédrale de Reims" from 1906 by the Swiss artist Annie Stebler-Hopf (1861-1918)....

One type of degradation commonly observed with paintings on absorbent canvas is flaking paint. Solutions to this degradation phenomenon are particularly challenging and the search for an ideal one-an ongoing one. This paper reviews and summarises approaches that have developed over the past decade at the Bern University of Applied Sciences. The goa...

Due to Edvard Munch's (1863-1944) unconventional painting technique, choice of materials, and the unstable climate conditions of his studios, where the paintings were stored during his lifetime, many of his paintings, now housed at MUNCH, have cohesively weak and loose paint layers. As a result, consolidation and re-adhesion of these fragile paint...

Many European sculptures and altarpieces from the Middle Ages were decorated with Zwischgold, a bilayer metal leaf with an ultra-thin gold face backed by silver. Zwischgold corrodes quickly when exposed to air, causing the surface of the artefact to darken and lose gloss. The conservation of such Zwischgold applied artefacts has been an obstinate p...

In: Structural treatments on double-sided paintings, edited by Centro Conservazione e Restauro La Venaria Reale, Genova 2022.

Adhesive meshes are micro-structured and honeycomb-shaped, flexible adhesive nets. They can be produced from a variety of adhesives such as water-soluble methylcelluloses or sturgeon glue. These two have proofed long-term stability for several decades now and have found wide application in the field of conservation. If a painting allows for tempora...

It is no secret and yet not all pilgrims know that the “black Ma- donna” from the Einsiedeln monastery in central Switzerland, dated in the 15th century, originally had a white incarnate and was painted over in black in 1799. According to a very early documentation, the reason given was the optical regression to the rusty appearance. This colour ch...

This study investigates invasive and non-invasive methods to determine penetration and deposition of adhesives using a combination of non-invasive unilateral NMR techniques and fluorescent labelling. Results show that unilateral NMR can be used to gather real-time information on the penetration and evaporation of the carrier as well as tracking sol...

In this article, we discuss the strengthening of methyl cellulose with nanocrystalline cellulose and microfibrillated cel- lulose for high relative humidity (75%, 84%, 97%) during re-adhesion of chalk ground. Methyl cellulose is the least hydrophilic cel- lulose ether among the water-soluble ones. Its long-term stability is very high. It has good t...

Augusto Giacometti’s painting The Circling of the Planets (1907; 268 × 218 cm) is in a highly fragile state, suffering from widespread flaking paint. These flakes are very brittle and rigid; none of the usual consolidation techniques managed to achieve necessary ductility to secure lifting paint flakes. In the blue areas, both absorbent protein-oil...

This new canvas bonding method uses pure methyl cellulose, sturgeon glue or butyl methacrylate as thin, microstructured adhesive meshes. The bonding procedure is carried out by positioning the mesh in its dry state, activating it with a controlled supply of moisture or solvents, and applying pressure to generate the adhesion. The approach follows g...

At first, the challenges of gluing paint flakes to absorbent canvas are presented, followed by the approach and the criteria, which culminate in a short outline of the selection of the adhesive and the possibility to control the flow of the adhesive.Afterwards this article shows the pre-wetting effect and masking mechanism of two aliphatic, non-aro...

A new bonding system for the reinforcement of paintings made on textile supports will be presented. These are self-supporting, flexible meshes produced of a series of pure and well-established conservation adhesives. The main focus will be set on methylcellulose. Technically, the procedure involves positioning of the mesh in dry state, activation w...

Augusto Giacometti’s painting The Circling of the Planets (1907; 268 × 218 cm) is in a highly fragile state, suffering from widespread flaking paint. These flakes are very brittle and rigid; none of the usual consolidation techniques managed to achieve necessary ductility to secure lifting paint flakes. In the blue areas, both absorbent protein-oil...

When working with low viscosity adhesives on canvases without a sizing layer, it is advisable to mask the canvas prior to consolidation (for example with CDD solutions). The use of fuorochrome-labelled gelatine (type A, ,,, Bloom mm w/w in distilled water) in combination with huorescence microscopy allows the sealing eeect of various methods of cyc...

Zwischgold (also part-gold in English) is a two-layered metal foil made of gold and silver that was historically applied to altarpieces, sculptures and panel paintings. It tends to oxidize quickly in air and therefore was usually applied with a protective varnish layer. The purpose of applying Zwischgold is an interesting topic in the research of a...

Modern oil paints are often optimized by the artist himself in the course of experiments. Unfortunately, the outcome is not always as expected by the artist. In the case of Augusto Giacometti's „The Circling of the Planets" (in german: "Das Kreisen der Planeten“) from 1907, for example, the artist had to struggle with the degradation phenomena flak...

Da neben den Materialeigenschaften von Konsolidierungsmitteln vor allem die präzise Platzierung des Klebstoffs von hoher Bedeutung ist, zeigt die vorliegende Arbeit, wie lose, gerade Bildschollen auf textilem Bildträger mit den gängigen Kon- solidierungsmitteln (Gelatinen, Störleim und Methylcellulose) möglichst nur durch eine Klebschicht ohne Subs...

Es wurde untersucht, ob es mit dem Zuschlagstoff Nanocellulose möglich ist, bei gleichbleibender oder erhöhter Klebkraft die Viskosität der Methylcellulose (MC) herunterzusetzten. Es wurden eine mikrofibrillierte Nanocellulose (MFC) der EMPA Schweiz und zwei verschiedene kristalline Nanocellulosen (NCC) verwendet. Geprüft wurden die Auswirkungen de...

Es wurde untersucht, ob es mit dem Zuschlagstoff Nanocellulose möglich ist, bei gleichbleibender oder erhöhter Klebkraft die Viskosität der Methylcellulose herunterzusetzten. Geprüft wurden die Auswirkungen des Zuschlagstoffes auf Verarbeitbarkeit und Klebkraft. Zudem wurde getestet, welche Mischsysteme sich am besten für eine homogene Vermischung...

A new approach allows the use of water-soluble adhesives for joining canvases by lowering the introduction of moisture: Adhesive meshes consist of pure binding media – gelatine, sturgeon glue or methyl cellulose – in the form of a very fine and flexible grid, which is applied dry and activated with a minimal amount of water. So far, this technique...

Zwischgold is a two-sided metal foil made by adhering a gold leaf over a silver leaf to present a gold surface while using less gold than gold foils. Corroded Zwischgold surfaces appear dark, accompanied by gloss loss and possible mechanical stability issues. Zwischgold applied artefacts are commonly found in museums and churches across Europe and...

Pre-wetting and masking during re-adhesion of delaminations on canvas paintings During re-adhering absorbent flaking paint with sturgeon glue or gelatines, one would often like to gain the widest lateral distribution in a joint, the lowest penetration into the substrate and at the same time an adequately good adhesion. In conservation, the pre-wet...

Le Lierre unique eunuque (The Unique Eunuch Ivy) is one of the later works in a series of mechanomorphic and was materially analysed in a master's thesis at the Bern University of the Arts in collaboration with the Kunsthaus Zurich. The most important results are presented here.

This paper shows the predominant parameters necessary for a successful masking with apolar solvents during the re-adhesion of flaking paint with water-based adhesives. As substrates, unisolated canvas, alkyd paint and chalk ground were used. The apolar masking was carried out with Isooctan, petroleum ether 100–140°C, ShellSol T, D70, D4 und D5 and...

Sturgeon glue and gelatines are often used as adhesives and consolidants in conservation. However, a more profound investigation of their properties to help practitioners make well-founded decisions is desirable. Linking adhesion tests to the visualisation of the penetration mechanisms using fluorescence labelling allows a deeper understand- ing of...