Preliminary art-technological and scientific analyses of Pedro de Mena’s Inmaculada Concepción, acquired in 2021, have shown that the sculpture’s original Baroque colour scheme not only differs from the later overpainting, but also far surpasses it in artistic and technical quality. Beneath the later, crudely applied, plastic-glossy layers of paint, an outstanding example of Pedro de Mena’s virtuoso painting technique has been preserved. One of the aims of the restoration was therefore to remove this overpainting and reveal the remarkable quality of the original polychromy.

On the basis of the preliminary examinations and extensive practical test-series, an individual, gentle procedure for removing the overpainting was carried out for each section of the original painting on the figure. With the help of numerous tiny test areas, it was possible to get an accurate overview of whether the original polychromy is well preserved and that the missing elements can be integrated in further work steps.

The preferred methods for removing the overpainting ranged from mechanical removal with extremely fine microsurgical scalpels to the use of suitable solvents, mostly processed into gels. Additional tools such as compresses and micro-sponges were also used. To ensure the highest precision and safety, these exposure procedures were carried out under a stereo microscope in months of painstaking detail work.

Between the original skin painting and the multi-layered white-pink overpainting, a monochrome grey-beige layer of paint was discovered, without any red modelling or fine drawing of eyebrows or mouth. This layer probably served as a kind of primer for the new colour scheme. This visually easily recognisable ‘guide layer’ greatly facilitated orientation during the exposure process.

In the partially exposed state, the qualitative difference between the original and the overpainting became particularly clear. While the red modelling of the original skin painting is lifelike and highly detailed, the later overpainting appears technically simpler, flatter and with only a few red accents. The virtuoso, finely detailed drawing of eyebrows and lips in the original colour scheme, which was worked into the still damp skin colour and is on a par with the painting technique of high-quality Spanish Baroque paintings, is completely absent in the later layers of overpainting.

It is particularly noteworthy that, unlike the overpainting, the original skin painting was not executed in an idealized, smooth and porcelain-like manner. Rather, the painters in de Mena’s studio strove to achieve the most realistic colouring possible. To this end, they used not only lifelike colour modelling, but also the different textures and light reflections of their paints. A viscous skin-coloured paint was applied with a brush to create a slightly rough, porous surface texture with silky matte light reflections, deceptively similar to human skin. This technique can already be seen in a very similar way in the realistic skin painting of late medieval sculptures.

The individually carved strands of hair on the sculpture were originally attached to the figure with glue and fine metal pins. During previous restorations, these connections were loosened and often reattached inaccurately or in the wrong position. The resulting gaps have been roughly filled with a putty that extends well beyond the original. Additionally, several layers of black-brown paint covered the originally very precisely cut strands of hair and made their shape appear soft and indistinct.

The individual strands of hair had to be detached from the figure in order to correct their position and remove the overpainting and putty. Afterwards, the sculptural quality of the hair and the nuanced, fine painterly rendering were restored. The original painting simulated dark blonde, slightly sun-bleached hair with light reflections. This was achieved probably by partially dabbing gold powder onto the still damp, sticky light brown paint, especially at the ends of the hair.

The overpainting of the mantle greatly simplified the original colour schemeby covering the red inner lining and the blue outer surface with a dark blue, glossy resin oil paint. The removal of the overpainting gradually revealed the original painting of the mantle’s lining, which probably depicts red velvet brocade with floral ornaments and blue silk.

To imitate the specific texture of the velvet pile and the metallic sheen of such a textile, it was necessary to apply multiple layers of paint. First, an adhesive paint was applied directly to the primer, into which a fine, sand-like strewing material was added. Silver leaf was then applied to this adhesive layer. This gave the resulting silvering the desired velour-like surface texture and slightly softened the intense light reflection of the silvering to a silky matte finish. The surface was then coated with a semi-transparent red lacquer to create a reddish-metallic colour effect known as glazing. Finally, the floral pattern was applied with a thick, dark red lacquer.

Although the colouring of the overpainting on the outside of the mantle was based on the blue colouring of the original, the technical quality could hardly be more different. Like the overpainting on the lining of the mantle, the overpainting here is glossy and opaque, more in keeping with those paints that were never intended to imitate the illusionistic effect of a fabric. The situation was quite different with the original colour scheme. This was done using a two-layer polychrome painting technique that was widespread at the time and subtly created the material illusion of silk.

First, the painter carefully applied an evenly opaque layer of light blue paint. This consisted of fine white pigment and relatively coarse-grained blue pigments bound with animal glue. After this layer had dried, another layer of paint was applied, which was very different from the first: it was more heavily enriched with crystalline blue pigments. It was applied with quick brushstrokes, creating a stringy texture that partially covered the lighter layer of paint underneath.

Seen up close, the resulting colouration appears patchy and unclean. Only from a distance does the intended visual effect become apparent: the irregularity of the texture and the application of paint create the striking illusion of a loose, airy fabric, strongly reminiscent of finely woven mulberry silk.

The later cold white paint layers of paint on the Virgin’s robe concealed an elaborately painted textile imitation.

The original painting shows a matte, ivory-coloured base tone, on which parallel lines of paint made out of real gold powder were drawn to create a chequered pattern, no doubt alluding to a moiré fabric interwoven with gold threads. The lining of the dress was originally designed with a metallic greenish shimmering glazing on silverleaf application, which was also concealed by the overpainting.

The original lustrous silvering on dark red poliment has been almost completely lost, with only small remnants remaining. Restoration efforts focused on removing the numerous putty fillings, the thick over-priming and the subsequent layers of paint. This was necessary, on the one hand, because these later additions had obscured the fine carving of the face of the moon and, on the other hand, because the lustrous silvering of the overpainting had been completely lost. The restoration plan now envisages the reconstruction of the lustrous silvering of the moon, which has been uncovered on one fragment, together with the reconstruction of the base, on the basis of the material examination of the original and comparable works by de Mena. Of course, the remaining parts of the original painting will be masked for protection, and the reconstructed lustrous silvering will be identified as a later addition by means of fine-point retouching.

The conservation work has significantly reavealed the Inmaculada’s original polychrome appearance, which had been disfigured by later overpainting. De Mena’s original colour scheme, now visible, is of high artistic and technical quality. This is not only based on the colour effect but also includes the specific surface textures and light reflections of the fine painting, which make the artist’s already very lifelike carving appear even more vivid and realistic.

Forthcoming issues of Research & Journal will report on the international professional collaboration and exchange with international experts in the research and the restoration of de Mena sculptures, which will be essential for the integration of the missing parts and in particular for the reconstruction of the completely lost parts of our Inmaculada, such as the base construction and the aureole.