dhr. prof. dr. E.R. de la Rie

  • Faculteit der Geesteswetenschappen
    Capaciteitsgroep Conservering en Restauratie
  • Bezoekadres
    Johannes Vermeerplein 1  
  • Postadres:
    Johannes Vermeerplein  1
    1071 DV  Amsterdam
  • E.R.delaRie@uva.nl

Research into consolidating adhesives for the conservation of painted cultural objects

Many different materials are in use to re-adhere and consolidate flaking paint layers on cultural objects. In the 20th century, synthetic and semi-synthetic products were introduced as replacements for traditional, natural consolidants, which may be unstable, leading to discoloration and other modes of failure. Although some synthetic products are more stable than their natural counterparts, many have undesirable properties such as inability to penetrate into the paint crevices, poor adhesion and undesirable optical changes. Few of these materials have been developed specifically for the conservation of cultural objects nor have they been tested for this purpose. No attempts have been made to formulate them to obtain the appropriate chemical and physical properties, nor do they take advantage of recent advancements in adhesive technology.

The current research aims at understanding the properties required to consolidate painted cultural objects and to develop products tailor-made for this purpose. The study involves chemical synthesis and chemical modification of extant materials. These and currently used consolidants are being characterized using NMR, PyGCMS, FTIR, SEC, rheometry, DMA, DSC, TGA, probe-tack testing, peel, tensile and shear resistance tests, among other methods. The stability of the materials is being evaluated using accelerated aging methods and the effects of stabilizing additives, such as hindered amine stabilizers is being examined. Application tests of experimental formulations are being carried out by conservators and distributors and formulators for successful formulations will be sought.

This research recently received funding from NWO under the new NICAS initiative (http://www.nwo.nl/onderzoek-en-resultaten/programmas/ew/nicas/index.html). The work will be carried out in a collaboration among the universities of Delft and Amsterdam, as well as the Stedelijk Museum, Rijksmuseum, SRAL and other organizations.

Current partners

- E. René de la Rie, University of Amsterdam & Centre de Recherche sur la Conservation des Collection (CRCC), Paris 
- Hans Poulis, Chelsey Del Grosso, Adhesion Institute, TU Delft 
- Lydia Beerkens, SRAL, Maastricht
Sandra Weerdenburg, Stedelijk Museum
Petria Noble, Rijksmuseum
- Rebecca Ploeger, Buffalo State, SUNY
- Chris McGlinchey, Museum of Modern Art, New York, NY
- Oscar Chiantore, Tommaso Poli & Dafne Cimino, University of Torino
- Robert Proctor, Whitten & Proctor Fine Art Conservation, Houston, TX


 - E. René de la Rie, “Kleefstoffen en Coatingmaterialen voor het Conserveren van Culturele Objecten vs. Trends in het Natuurwetenschappelijk Onderzoek,” Innovatie in de Conservatie-Restauratie: Opportuniteiten en Beperkingen/Innovation en Conservation-Restauration: Opportunités et Limites, Postprints, Ed. Marjan Buyle, BRK-APROA/Onroerend Erfgoed, Brussel 2016, pp. 26-31.

- Dafne Cimino, Oscar Chiantore, E. René de la Rie, Christopher W. McGlinchey, Rebecca Ploeger, Tommaso Poli and Johannes A. Poulis, “Binary mixtures of ethylene containing copolymers and low molecular weight resins: A new approach towards specifically tuned art conservation products,” Int. J. Adhesion & Adhesives 67 (2016) 54–62. http://dx.doi.org/10.1016/j.ijadhadh.2015.12.026.

- Rebecca Ploeger, Christopher W. McGlinchey and E. René de la Rie, “Original and Reformulated BEVA® 371: Composition and Assessment as a Consolidant for Painted Surfaces,” Studies in Conservation 60 (2015) 217-226. http://dx.doi.org/10.1179/2047058414Y.0000000132.

- Rebecca Ploeger, E. René de la Rie, Christopher W. McGlinchey, Michael Palmer, Christopher A. Maines and Oscar Chiantore, “The long-term stability of a popular heat-seal adhesive for the conservation of painted cultural objects,” Polymer Degradation and Stability 107 (2014) 307–313. http://dx.doi.org/10.1016/j.polymdegradstab.2014.01.031.

- Christopher McGlinchey, Rebecca Ploeger, Annalisa Colombo, Roberto Simonutti, Oscar Chiantore, Robert Proctor, Bertrand Lavédrine and René de la Rie, “Lining and Consolidating Adhesives: Some New Developments and Areas of Future Research,” CCI Symposium on Adhesives and Consolidants for Conservation (2011), http://goo.gl/SyoYN.


Degradation of cellulose at the wet-dry interface: “tidelines” in paper

Formation of brown lines at the wet-dry interface in cellulosic materials such as paper has been described in many publications, some of which date from as far back as the 1930s. Despite various research efforts, the mechanism of the formation of these so-called “tidelines” is not fully understood. A tideline can be produced by suspending a strip of paper vertically with the lower end immersed in water.  The water will rise in the strip through capillary action until equilibrium is reached when the capillary rise is offset by evaporation.  Within hours a brown line forms at the wet-dry interface. Fluorescence can be detected in the tideline area even earlier.  Brown lines can be generated in Whatman paper, consisting of pure cellulose, and using distilled water. A better understanding of these phenomena is of relevance to the conservation, storage and the treatment of cultural objects made of paper and to a better understanding of cellulose degradation in general. Local conservation treatments in particular may involve the formation of tidelines.

In this study, the molar mass of cellulose in the tideline and other areas of the paper sheet is being studied using SEC/MALS. Quantitation of hydroperoxides and hydroxyl radicals using reverse phase chromatography with triphenylphosphine and terephthalic acid, respectively, as chemical probes has provided evidence of oxidation reactions. Different types of antioxidants have been added to the paper to investigate their effect on the oxidation reactions taking place.          

Current partners

- E. René de la Rie, University of Amsterdam & Centre de Recherche sur la Conservation des Collection (CRCC), Paris 
- Anne-Laurence Dupont, Myung-Joon Jeong & Bertrand Lavédrine, Centre de Recherche sur la Conservation des Collection (CRCC), Paris


- Myung-Joon Jeong, Anne-Laurence Dupont and E. René de la Rie, “Degradation of cellulose at the wet-dry interface. II. Study of oxidation reactions and effect of antioxidants,” Carbohydrate Polymers 101 (2013) 671–683. http://dx.doi.org/10.1016/j.carbpol.2013.09.080
- Myung-Joon Jeong, Anne-Laurence Dupont, and E. René de la Rie, “Degradation of cellulose at the wet-dry interface: I. Study of the depolymerization,” Cellulose 19 (2012) 1135-1147. http://dx.doi.org/10.1007/s10570-012-9722-4 
- Zied Souguir, Anne-Laurence Dupont and E. René de la Rie. "Formation of Brown Lines at the Wet-dry Interface in Cellulosic Materials," Biomacromolecules 9, no. 9 (2008) 2546–2552.http://dx.doi.org/10.1021/bm8006067


Research into the degradation of ultramarine blue containing paint layers

Fading, “blanching,” “whitening” or “greying” of ultramarine blue containing paint layers has been described by many and the term “ultramarine sickness” has frequently been used to describe the degradation of such paint layers. A clear explanation for the color changes however has never been given and there are also many examples of well-preserved ultramarine blue paint layers. In a new study, the changes in several ultramarine blue containing paints are being studied using accelerated aging and various analytical methods. The work is carried out at CRRC, Paris, TU Delft and other institutions.

Current Partners

- E. René de la Rie, University of Amsterdam & Centre de Recherche sur la Conservation des Collection (CRCC), Paris
- Anne Michelin and Manuela Ngako, Centre de Recherche sur la Conservation des Collection (CRCC), Paris
Eleonora Del Federico, Pratt Institute, New York, NY
- Chelsey Del Grosso, TU Delft
- Robert Gamblin, Gamblin Artist Colors, Portland, OR
- Katrien Keune & Alessa Gambardella, Rijksmuseum, Amsterdam


- E. René de la Rie, Anne Michelin, Manuela Ngako, Eleonora Del Federico, Chelsey Del Grosso, "Photo-catalytic degradation of binding media of ultramarine blue containing paint layers: A new perspective on the phenomenon of 'ultramarine disease' in paintings," Polymer Degradation and Stability 144 (2017) 43-52. https://doi.org/10.1016/j.polymdegradstab.2017.08.002

Stability and Optical Properties of Natural and Synthetic Resins Used for Varnishing and Retouching


Artists have commonly applied a final transparent coating to the surface of oil and tempera paintings. A general misconception is that these varnishes need to be applied for protective reasons, but in fact little protection is provided by them. Their aesthetic function however is important, as varnishes have the ability of changing the appearance of paintings dramatically, affecting such properties as color saturation and gloss. A varnish is, therefore, an essential part of a painting if it originally had such a layer, but should not be applied if the painting was meant to be left unvarnished. With the change in artists' materials and techniques arising in the late nineteenth century came a decline in the use of picture varnishes, although they are still applied by many artists today. Throughout the centuries, many different materials have been used to prepare varnishes.

Varnishes are the most vulnerable components of paintings, as the large surface-to-volume ratio of these thin layers of organic material maximizes their exposure to the deteriorating effects of the environment. Traditional picture varnishes, which are based on natural materials, deteriorate over time, causing yellowing, loss of transparency, and, eventually, cracking. Because these degraded varnishes obscure the images beneath them, they are removed periodically in conservation treatments and replaced by new ones. Removal of varnish layers (referred to as “cleaning” in the field) is a process that involves risks for the paint surface, as often strong solvents or other materials and methods are required. Artists and conservators alike have long sought more stable varnish materials. Many of the modern polymeric materials that have been tried ever since their introduction in the 20th century provided an appearance different from that produced by traditional materials. They also sometimes proved to have stability problems of their own.

Careful consideration of the drying process of solvent-based varnishes has led to the insight that natural resin varnishes, which are of low molecular weight and hence produce solutions of low viscosity, level to a greater extent over the microscopically rough paint surfaces than polymeric varnishes. These optically smoother surfaces scatter less light, produce higher gloss and more saturated colors. Differences in refractive index play a minor role. The appearance obtained with traditional varnishes can be mimicked therefore using synthetic resins of low molecular weight. The stability of such resins was studied extensively using accelerated aging in a simulated indoor museum environment. Hindered amine light stabilizers (HALS) were also extensively tested. Synthetic low molecular weight resins and HALS are now used worldwide by conservators and artists. 

Retouching Paints

Paints used for retouching often have similar requirements, in that a stable synthetic low molecular weight binder is needed to provide an optically smoother surface. Such paints provide more saturated colors. Retouching paints based on a synthetic low molecular weight resin were extensively tested and are now commercially available and widely used by painting conservators.


Many publications can be found in this list. Below is a selection. See National Gallery of Art for other research activities.

- E. René de la Rie, John K. Delaney, Kathryn M. Morales, Christopher A. Maines and Li-Piin Sung, “Modification of surface roughness by various varnishes and effect on light reflection,” Studies in Conservation 55 (2010) 134–143.

- John K. Delaney, E. René de la Rie, Mady Elias, Li-Piin Sung and Kathryn M. Morales, “The role of varnishes in modifying light reflection from rough surfaces.  A study of changes in light scattering caused by variations in varnish topography and development of a drying model," Studies in Conservation 53 (2008) 170–186.

- Mady Elias, E. René de la Rie, John K. Delaney, Eric Charron and Kathryn M. Morales, “Modification of the surface state of rough substrates by two different varnishes and influence on the reflected light,” Optics Communications, 266 (2006) 586-591 (http://dx.doi.org/10.1016/j.optcom.2006.05.051).

- Christopher A. Maines and E. René de la Rie, “Size-exclusion chromatography and differential scanning calorimetry of low molecular weight resins used as varnishes for paintings,” Progress in Organic Coatings 52 (2005) 39-45.

- E. René de la Rie, Suzanne Quillen Lomax, Michael Palmer, Lisha Deming Glinsman and Christopher A. Maines, “An Investigation of the Photochemical Stability of Urea-Aldehyde Resin Retouching Paints: Removability Tests and Colour Spectroscopy,” Tradition and Innovation: Advances in Conservation, IIC 2000 Melbourne Congress, International Institute for Conservation of Historic and Artistic Works, London 2000, 51-59.

- Mark Leonard, Jill Whitten, Robert Gamblin and E. René de la Rie, “Development of a New Material for Retouching,” Tradition and Innovation: Advances in Conservation, IIC 2000 Melbourne Congress, International Institute for Conservation of Historic and Artistic Works, London 2000, 29-33.

- E. René de la Rie, Conservation Science Unvarnished, Oration delivered on the assumption of the special chair for the chemistry of conservation and restoration at the University of Amsterdam, 30 October 1997, Stichting Bijzondere Leerstoel voor de Chemie van Conservering en Restauratie, Amsterdam 1999.

- E. René de la Rie, "Stability and Function of Coatings Used in Conservation," Polymers in Conservation, eds. N. S. Allen, M. Edge and C.V. Horie, Royal Soc. Chem., Cambridge 1992, pp. 62-81.

- E. René de la Rie and Christopher W. McGlinchey, "New Synthetic Resins for Picture Varnishes," Cleaning, Retouching and Coatings, eds. J. S. Mills and P. Smith, International Institute for Conservation of Historic and Artistic Works, London, 1990, 168-173.

- E. René de la Rie and Christopher W. McGlinchey, "The Effect of a Hindered Amine Light Stabilizer on the Aging of Dammar and Mastic Varnish in an Environment Free of Ultraviolet Light," Cleaning, Retouching and Coatings, eds. J. S. Mills and P. Smith, International Institute for Conservation of Historic and Artistic Works, London, 1990, 160-164.

- E. René de la Rie, "Old Master Paintings: A Study of the Varnish Problem," Analytical Chemistry 61 (1989) 1228A-1240A.

- E. René de la Rie and Christopher W. McGlinchey, "Stabilized Dammar Picture Varnish," Studies in Conservation 34 (1989) 137-146.

- E. René de la Rie, "Photochemical and Thermal Degradation of Films of Dammar Resin," Studies in Conservation 33 (1988) 53-70.

- E. René de la Rie, "The Influence of Varnishes on the Appearance of Paintings," Studies in Conservation 32 (1987) 1-13.





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