- The altarpiece of Saint Dominic of Silos by Bartolomé Bermejo
- The evolution of preparations for painting on canvas in sixteenth and seventeeth century Spain
- Study of the Prado Museum's copy of La Gioconda
- Technical and restoration study on the collection of Miniatures in the Museo del Prado
- The Wine of Saint Martin’s Day. Pieter Bruegel the Elder
Among inappropriate, earlier restoration methods the most significant was the incorrect application of adhesives both to stick down pieces of paper or card on the back and to support the miniature in the frame. We encountered two types of adhesive that were analysed in the laboratory. 6 The first was a stable, transparent one that was found both in original joins and in subsequent interventions and which was identified as a gum. The second was an animal-type glue that was only found in later restorations. It is grey-brown in colour and in some cases has left patches on the ivory. In cases when these adhesives derive from subsequent intervention and in general whenever possible, they were removed as they can result in tensions and stains fig. 20. In addition, when the adhesive were applied in these old restorations the paint layer was sometimes stained, particularly at the edges fig. 21. The most serious damage of this type was found in Portrait of a Lady with Flowers in her Hair and a green Dress (O-699), as this work may have suffered an accident in which adhesive spilled onto the area of the dress. Fortunately, we were able to remove this patch of animal glue by mechanical means fig. 22.
With regard to the paint layer, we found few cases of old repainting and these were only located in thickly painted background areas, possibly because repainting intended to cover over damage would be too thick and opaque over flesh tones and transparencies. Interestingly, we found miniatures that had been repainted from the back: using the transparency of the ivory some elements were reinforced in this way, for example, Portrait of an Officer in uniform Jacket (O-717) and Venus and a Satyr (O-680), in which the officer's face and the flesh tones of the bodies had been strengthened respectively fig. 23 - fig. 23.1. In other cases varnishes or adhesives had been applied to intensify or 'fix' the colours, as in Portrait of Isabel II (O-698). Unfortunately, the application of this project resulted in craquelure and losses to the paint surface fig. 4.
Another problem was that of abrasions to the paint. The most serious cases were found in miniatures that had lost the glass of the frame, such as Akbar the Great (O-745) in which almost all the polychromy had been lost due to abrasions. In other cases, such as Portrait of a Knight of the Order of Calatrava (O-703), the abrasions were the result of a new sheet of glass that was flat and had sharp edges fig. 27. Even original pieces of glass with curved edges can damage the paint surface and produce shiny areas and scratches if the glass has swollen or moved.
Finally, damage was encountered resulting from poor handling. Given that miniatures are extremely small, delicate items the way in which they are treated can leave permanent marks. The most habitual type of damage is that of fingerprints on the paint: sweat from hands is damp and greasy and varies in acidity depending on each person. These factors affect the paint layer and while deterioration is not immediately evident, dark fingerprints become visible with the passing of time dark fig. 29. Sneezing also leaves its mark on the paint surface. Another problem is the practice of cutting down the ivory support, which was generally done to eliminate damaged areas, however, in the case of Portrait of a Man with long Hair and Moustache the miniature was cut down with scissors to adapt it to the frame fig. 30.