Voici deux articles sur le doublage transparent que j'ai retrouvé. Hélas! en anglais et dont j'ai perdu la source.
J'espère que ça pourra vous servir.
Question : Berger n'a t il pas conçu la béva pour réaliser des doublages transparents?
This paper provides a survey of previously described transparent linings of paintings. This is followed by the description of a transparent cold-lining of a transparent oil painting on a starch-impregnated cotton canvas. The cold-lining was done with Plexrol B500 on a polyester fabric Po1ymon PES 65/36, using a 1ow-pressure table.
Transparent lining, cold-Lining, transparent painting, polyester fabric, Polymon, Stabiltex, Plextol B 500, solvent re-activation, low-pressure table
Transparent Cold-Lining of a Transparent Painting
Soren Bernsted Conservator of Paintings Faelleskonserveringen
Art Conservation Center Kronborg 10 b
DK-3000 Elsinore, DenmarkIntroduction
The conservation of paintings has undergone rapid development, particularly within the past decades. This is mainly due to the advent of synthetic polymers in, for example, binding agents. The development has not been nearly as rapid for painting canvases, especially as regards transparent support canvases.
The earliest described transparent back support was made on a rigid vinyl sheet with a copolymer vinyl resin. This was described by S. Keck in 1940 (1). About 20 years later, A. Boissonnas introduced a wax-lining made on a fiber glas fabric (2). For a long period of rime, this type of lining support was prevalent. Subsequently, the method was improved by E. Pacoud-Reme, who described in 1981 how to produce the translucent pure wax/resin mixture for transparent linings (3).
However, fiber glas fabric for lining failed to provide sufficient support to prevent the return of planar distortions in severely distorted surfaces. To circumvent this problem, G. Berger used a sandwich design of Mylar, fiber glas fabric, and BEVA(R) (4). Berger later described several different transparent linings with BEVA(R) and fiber glas canvases. As a replacement for sandwich linings, in 1981, Albert Albano described how to support the fiber glass canvases with Akemi, a transparent flowing polyester resin (5).
Suitable fiber glas canvases are rarely available, however, in widths exceeding 1.2 m (47.24"). To my knowledge, fiber glas canvases exceeding 1.2 m are of such heavy-duty quality that their transparency quality is, unfortunately, much impaired.
Previously, if you wanted to avoid joins and nevertheless wanted to make a transparent lining, these two objectives have been almost incompatible when the smallest dimension of the painting exceeded 1.2 m. I have, therefore, investigated this marrer in regard to what other types of transparent canvases are available.
Thin polyester canvases have a very satisfactory transparency. The Schweizerische Seidengazefabrik is a manufacturer of both the monofilament Polymon canvas and the multifilament Stabiltex canvas. They are available in widths up to 2.7 m (66.92"). Monofilament means that each thread has been produced from one fiber, whereas the multifilament quality has been produced from several thin fibres spun into one thread.
I found that the monofilament Polymon canvases had the highest transparency. Contributing to this, in the case of multifilament threads, there is a greater risk that air pockets are formed in the thread between the spun fibers. Furthermore, the Polymon canvases are slightly more rigid than the Stabiltex canvases. Thus, the Polymon canvases work better in preventing a return to planar distortions.
Polymon-fabrics can be obtained in several finenesses of weave. Thread diameters range from 27 micrometers for the finest fabric to 1000 micrometers for the coarsest fabric (6).
There are several advantages of Polymon-fabrics, according to the manufacturer:
1. Tensile strength: (Dry) From 45-60 kg/mm2 (65,000-85,000 psi); (Wet) 100% of dry strength.
2. Dimensional stability: Excellent.
3. Lors- moisture-absorption: At 65% RH and 25°C approximately 0.4%;
95°é RH and 25°C approximately 0.5%.
4. Chemieal resistance: Polyester fabrics are highly resistant to attack by solvents and chemicals. On1y some phenolic compounds and hot nitrober.zene dissolve the fabric.
5. Durability: Polymon-tabrics are flot atfecte3 bv ultravioletradiation and have a good resistance to oxidizing agents. In addition, they have an estremelv good resistance to decay, bacteria, etc.
Conservation of a transparent painting
The painting in this study originates from the masonic-related society known as "Kjxden" (the Chain). It is an allegoric painting attributed to a Danish painter, Nicolaj Abildgaard, in 1783.Technique
The painting is circular, measures 2.53 m(99.6") in diameter, and is stretched tightly onto a collapsible stretcher. The painting is painted with oil paint on a starch-impregnated cotton canvas. This type of support is normally used as painting ground in the transparent painting technique, as it is much more translucent than gesso-grounded linen canvases.
In the transparent painting technique, each individual layer of paint in the painting has to be transparent in order te, attain the transparency effect. Light and dark color areas are created by varying the thickness of the paint layer. Thus, thick paint layers will produce dark colors.
Transparent paintings are not automatically translucent. While paintings generally are to be viewed in reflected light, transparent paintings should be viewed in a mixture of transmitted and reflected light. The greatest effect is attained with transmitted light only. This means that the materials used for the conservation of such paintings have to meet special requirements. All materials have to be as transparent as possible.Condition
The cotton canvas was in a very critical state prior to treatment. The canvas threads were very deteriorated and, therefore, they broke easily. The left half of the painting had a cross-shaped tear running 80 cm (31.5") in the vertical direction and 45 cm (17.7") horizontally. The damage had been secured locally with patches earlier on, but these had prevented the light from passing through. This part of the painting, therefore, appeared black. In addition, the painting had several large and small tears and holes (Sec fig. 1). The starch was stable, but forms of illumination used in the past, such as tallow candles, oil lamps, and gas lamps, had discolored the reverse side of the canvas.Conservation
The largest tears of the painting were locally secured with polyester fabric Polymon PES 65/36 impregnated with BEVA(R) 371. Minor tears were secured with dried BEVA(R) by bonding the edges of the tears with tiny pieces of adhesive and a hot spatula.
The painting was then mounted on a stretcher and humidified in order to subsequently remove planar distortions on a low-pressure table (7). After humidification, it was remarkable how the crumbled canvas regained its previous strength. Next, the reverse side of the painting was cleaned with water with an admixture of Agepon.
The transparent painting had been painted on a starch-impregnated cotton canvas. In order to prevent the binding agent of the cold-lining from penetrating the painting, the reverse side of the painting was sized with corn starch. The polyester fabric Polymon PES 65/36 was stretched onto a work frame, and then n"'e thin coats of Plextol B 500 were applied (
. Each coat was allowed to dry :-r 12 hours bet-ween applications. The binding agent was next activated with _ t_s..-applied toluene after «-hich the Po1ymon fabric was placed on the reverse ~_:1~: painting. This cold-iining took ~la~e on a low-pressure table.
Schweizerische Seidengazefabrik has several types of polvester fabrics, but in
this particular case I found that the polyester fabric Polymon PES 65/36 was
the mot suitable. Figure 2 shows the painting after conservation.
The results of the conservation treatment of the transparent painting described in this paper showed that the thin polyester fabric Polymon PES 65/36 was
very suitable for a transparent lining. The polyester fabric is available in widths up to 2.7 m(66.92"), should treatment require large, unjoined pieces of fabric
to line paintings.
The painting was restored in the autumn of 1989. Since that time, no changes in the painting surface, structural distortions, tears, or yellowing of the materials
used have been observed.
I wish to thank "The National Workshops for Art & Crafts, Old Dock Warehouse", Copenhagen for making the conservation facilities available during this conservation process. I also wish to thank conservator Mr. Steen Bjarnhof for making it possible to use these very excellent facilities.Materials
Stabiltex & Polymon. Schweizerische Seidengazefabrik AG Zürich, Grütlistrasse 68, Postfach, CH-8027 Zürich 2, Switzerland.
BEVA(R) 371. Heat-activated adhesive (composition). Lascaux Restauro. Alois K. Diethelm AG, Farbenfabrik, CH-8306 Brüttisellen, Schweiz.
Plextol B 500 (methyl methacrylate copolymer emulsion). Known in USA as Rohamere B 500. Rühm GMBH Chemische fabrik, Postfach 4242, Kirschen
allee, D-6100 Darmstadt 1, Germany.
Agepon. Wetting agent (composition). Agfa-Gevaert, D-5090 Leverkusen 1, Germany.
1. Sheldon Keck, "The Transfer of a Small Icon to a Support of Vinyl Resin," Technical Studies 9 (1940): 11-20.
2. Alain Boissonnas. "Relining with Glass-Fiber Fabric," Studies in Conservation 6 (1961):
3. E. Pacoud-Reme, "Trois cas de rentoilage transparent faits par G. Ten Kate au service de la restauration de peintures des musées nationaux" (Paper delivered at the Sixth Triennial Meeting of the International Council of Museums Committee for Conservation, Ottawa, 1981), 2/11-1.
4. Gustav A. Berger, "Unconventional Treatments for Unconventional Paintings," Studies in Conservation 21, no. 3 (1976): 115-128.
5. Albert Albano, "A Semi-rigid Transparent Support for Paintings Which Have Inscriptions on their Fabric Reverse and Acute Planar Distortions,"Journal of the American Institute for Conservation 20, (1981): 21-27.
6. Schweizerische Seidengazefabrik AG Zürich, Grütlistrasse 68, Postfach, CH-8027 Zürich 2, Switzerland.
7. Volker Schaible, "Reflexions sur la formation de cuvettes à la surface des peintures sur toile" (Paper delivered at the Ninth Triennial Meeting of the International Council of Museums Committee for Conservation, Dresden, 1990), 139-144.
8. V.R. Mehra, "Further Developments in Cold-lining (Nap-bond System)" (Paper delivered ai the Fourth Triennial Meeting of the International Council of Museums Committee for Conservation, Venice, 1975), 11/5-1.