Sōkō conservation for oversized sketches by Sorolla
We can’t help it: conservators are passionate about our profession.
Facing the conservation of more than 30 oversized Sorolla sketches, is something difficult to imagine at a first glance. While having lunch with Gemma, she was explaining to us the details of how they were doing the conservation treatments of these sketches of the Visions of Spain, by Sorolla, and we kept on asking more and more details, until the point that Gemma simply said:
-Just come over one day and see it, and then you will perfectly understand it.
And she is right: conservation cannot be learned only by reading or watching YouTube videos, and therefore Aida Nunes (coordinator of the conservation studio of Lisbon Museum), from Portugal, Javier Bueno (professor in the Conservation Department, University of Seville) and a servant, from Barcelona, took her word for it and we all agreed one day to see in person the procedures during the consolidation of one of these sketches.
Rather than helping, we actually participated in a master class, since everything was more than ready when we arrived. To the extent that they made it seem easy, but this is only because they had already made the conservation of around twenty of them beforehand.
The one that was scheduled to restore that day had already gone throughout the most thorough and minute treatment (removing the canvas lining from the back, cleaning, tears repair and others). However what must have been the most time consuming task was the previous study and analyses of the artworks, and evaluation of pros and cons in order to reach the final diagnosis on how to do the conservation treatments (case-by-case). The truth is that the decision making process is always the most difficult part.
But we weren’t there at this stage of uncertainty and headaches, we were only present for the fireworks: the lining, i.e. the reinforcement of the entire kraft paper from the reverse, with two layers of Japanese tissues, pasted with wheat starch paste prepared according to the Eastern Japanese method. A genuine feast for the senses, because the Sorolla sketches represent the freshness, the genius and the creativity staged in its pure state. Furthermore, we can collaborate in its restoration, on behalf of the best of the conservation team at the IVCR+I, a leading institution regarding paper conservation, to which the Hispanic Society of America trusted this team for the conservation of one of their most precious (and large) paper artwork. And they certainly took the right decision, since the conservation treatment shares with the sketches this essentiality, this character of the minimal necessary  with a total effect. Nonetheless the restoration has been really successful, precisely because of this thorough study and diligent planning (I guess the same ones Sorolla had in his mind before the hands on sketching).
Summarizing very much, the consolidation consisted in humidifying the artwork, which was upside down on a wooden board, and later on apply washi (japanese paper, since everything was done the Sōkō -japanese- style: with hake (brushes) and other techniques that Luis Crespo from the National Library of Spain had taught us). The reinforcing lining overlap the artefact some centimeters around the edges, remaining those edges attached onto the wooden board in which we worked, that was somehow doing the role of a Karibari. 
These wooden boards had been prepared ad hoc, they are made with phenolic wood finished with wax, and they can be used instead of a Karibari (and being the scale so large, they were ideal).
Afterwards the sketches were left to dry out, process in which the paper naturally shrinks, tensions and flattens, like in the flattening under tension.
Once the sketch was completely dry and flat, the flaps on the edges were detached, loosing up the drawing, and some cuts on these flaps were made. These japanese paper flaps were attached on a rigid surface (made of Thycore, an acid free corrugated board), displayed behind heach sketch, and providing body to the artwork and allowing at the same time its perspiration.
A really simple solution in its conception, not at all invasive with the artwork, and with an excellent result.
After our visit many more was left to do: adding some stripes that covered the white areas with a similar tone to the drawing, retouching the losses (the in-painting was held by the painting conservators from IVCR+I), and other finishings.
Under my perspective, the nicest aspect of this conservation is that is not visible at all. One can’t tell it “restored”, it seems nothing ever happened to it. And precisely because the sketches show without , preserving their original features, keeping the roughly attached corrections by Sorolla, and -in sum- keeping the spontaneity, the fresh stroke and everything. Precisely because of this reason it is an excellent conservation which satisfies every goal: to preserve, the minimal intervention and grantig the future stability without limiting further treatments. But above all, since we are dealing with paintings, the visual result allows us to simply enjoy the artwork .
A conservation treatment that owes its efficacy to a good diagnose and planing, to a simple desing and an impecable execution. That is why it deserves my acknowledgement, and I hope your too, and I encourage you to vote for it at the EU Prize for Cultural Heritage / Europa Nostra Awards 2018:
I can’t thank Gemma enough for her generosity in showing such a complex process for really valuable artwork. We keep with us the best of souvenirs: learning from their experience right at their place.
And here’s a really nice video showing more about the Sorolla sketches and their conservation:
Gemma Contreras Zamorano, director of the IVCR+I (CulturArts Generalitat, Subdirección de Conservación, Restauración e Investigación), and also the conservators team from the paper section, who let us sneak in at their daily routine and share their knowledge with us: Ángel Calderón, Marisa Ferrando, Patricia Real and Gemma Contreras. It must be mentioned that not only them worked in the sketches, also painting conservators, physicists, photographers and a large etcetera.
And, in spite of not being present there, we owe a lot to Luis Crespo, conservator at the National Library of Spain, for teaching us such simple and wonderful techniques imported from Japan.
And I thank Aida Nunes and Javier Bueno, to join me in this adventure.
Valeria Orlandini, for revising this English version, and making it understable to English speakers.
 For the most curious, here’s a link about the Characterization of Sorolla’s gouache pigments by means of spectroscopic techniques (C. Roldán, D. Juanes, L. Ferrazza and J. Carballo, published in Radiation Physics and Chemistry #119 (2016), pp. 253–263.), a study held between the Instituto de Ciencia de los Materiales de la Universidad de Valencia (ICMUV) and CulturArts Generalitat, Subdirección de Conservación, Restauración e Investigación (IVCR+I).
 The well-known minimal intervention, a concept very much controversial. In my opinion we should always do only the least necessary, and not more. Which does not mean that we ought to do nothing at all, neither to prioritize local mendings to thorough interventions which solve major issues; it simply means that no unnecessary treatments should take place (according to my point of view).
 The Karibari panel, for those who don’t know, is a birch wooden structure similar to a japanese screen. It is like a grid frame that is covered both from the front and from the back side with several japanese paper layers, displayed in a particular way. It would be like a canvas on two sides, but instead of a canvas there are these two layers of paper. Those are impregnated on fermented persimmon juice (kakishibu, is the name of the juice, where kaki is persimmon) which give it a particular transpiratory capacity. This structure is also used in Japan to repair paper or silk artwork, and these techniques have been widely adopted in occident in the recent years, to increase the resorts in paper conservation.
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