Application of traditional Japanese technology in large format 20th century paper

Paper was used by great painters to do sketches. People often attribute sketches as minor artworks, but they are the first raw expression of the artist - where painters materialize their ideas and make mistakes. The Hispanic Society of America preserves an important collection of large sketches that Sorolla drew for the Library's project in this institution. The IVCR+i restored 32 of 170 sketches with a traditional Japanese method. Sorolla used a low quality paper to do this work, and he made collages of his own sketches. The technique used was called gouache, and made the restoration process difficult because water can dilute the pigments. These drawings had additional challenges for research, for instance, the cotton textile support which deformed them because cotton and paper behave differently with levels of humidity. Sorolla's sketches were studied with microphotography, IR reflectometry, UV images to assess the damage, X-ray Fluorescence, SEM/EDX, and FTIR to recognize pigments and adhesives (AAVV. Sorolla intimo. Bocetos de vision de Espana. Fundacion Bancaja 2015). The adhesive found was wheat starch, and the pigments employed were soluble in water, so it was necessary to develop a new restoration would not jeopardize the sketches, but still allowed thorough analysis. The cellulose ethers commonly employed in paper restoration lack the ability to preserve paper for centuries. So we decided to employ traditional Japanese technology to restore these sketches. Traditional Japanese technology is based on the use of wheat starch and handmade paper from vegetable fibres that reduce the stress on the drawing's laminations. This method began to be evident in Europe in the year 2000, and in these cases the difficulty of this research resided in large format applications. We studied the sketches one by one to adapt the method, because the stress of fibres was increased with the sketch size. In the ten smaller sketches a tension smoothing and a laminate were used to counter-fibre; in large sketches (150 x 200 cm) a double lamination to counter-fibre and paper fibre were carried out. This adaptation of the Japanese treatment allows to stabilize the tensions in the large format works for exhibition and storage. These works have been exhibited in Valencia, Alicante, Castellon and La Coruna, and have verified the effectiveness of the method to stabilize the deformations in the large formats.