Subject
The materials and techniques of 56 wooden panel paintings attributed to the painter Francisco João were investigated. The artworks are scattered among churches and chapels of the Alentejo region, now comprising the Districts of Évora, Beja and Portalegre.

The Painter
Francisco João lived in the city of Évora, in those days the second cultural centre of the country and worked for the whole Alentejo region. Although a regional master working under local patronage, mostly for the Church, Francisco João was a prestigious figure, owning important properties and slaves. He was a prominent member of the Holy House of Mercy - a charitable organization founded in 1498 by the Queen Regent D. Leonor - and from 1570 onward, he was the official painter of the Inquisition in the town of Évora. Francisco João was further known for being one of the first Portuguese artists to fight for the recognition of the Liberality of the Art of Painting, thus claiming a higher social and intellectual status for his profession (Serrão 1983, Kubler 1967). Nothing is known about his training, but the influence of the Spaniard Luis de Morales, el Divino, who also worked in Évora and lived just across the border, is recognized in much of his work (Espanca 1955-56, Serrão 1987). The close stylistic resemblance with the art of Morales is evident in the dramatic and piety facial expressions, with large eyes and plump lips. However, the simplified and immediate paint handling technique, along with the absence of the refined sfumato technique so characteristic of the flesh tones of el Divino expose the limits of this regional Portuguese master.
The painting production of this master clearly reflects the artistic reality of the country: the subjects depicted are exclusively religious, painted on wooden supports and commissioned to be part of altarpieces. Only seven of these paintings are preserved in museums, the majority being kept in their original location, sometimes in their altarpiece, more often removed from their original structure.

Methodology
The paintings were examined under incident and raking light (Vis), under ultraviolet radiation (UV) and with infrared photography and reflectography (IRR - Vidicom camera). Micro paint samples were collected and analysed with optical microscopy (OM) in reflection mode, under visible (OM-Vis) and ultraviolet radiation (OM-UV); with scanning electron microscopy (SEM) with energy dispersive X-ray spectrometry (EDX) and with Fourier transform infrared micro-spectroscopy (µ-FTIR). Some were also analysed using Micro-Raman spectroscopy (µ-RS) and high-performance liquid chromatography coupled to diode-array and mass spectrometry detectors (HPLC-DAD-MS).









Suports
Good quality oak (Quercus spp.) was used for the construction of all the panels and original altarpiece frames and structures. Although no dendrochronology was performed, it was possible to Identify the use of Baltic timber, due to the prensence of engraved marks in the back of some panels, that are related to the commerce and trade of that type of wood. The presence of moonrings  in some planks further indicated that oak from a northern climate, and not Portuguese, was used. The dimensions of the panels and individual boards was assessed. Their construction system, presence of woodworkers tools on the back and union to their altarpiece structure was investigated.














Preparatory layers
In general, a single white ground layer of gesso grosso bound in animal glue was used. Some painting exhibited a thin overall medium-rich imprimatura incorporating a little lead white and minium and, in one altarpiece, a little vermilion. The morphology of the grounds, their thickness and technique of application were investigated.


















Underdrawing
The underdrawing was visible in most of the paintings, as a dark gritty dry material, possibly executed using charcoal or a natural or fabricated black chalk. The underdrawing was characterized in terms of its position within the paint structure, the materials used and graphical layout. The role of the underdrawing in the painting process and its relation with the painted surface were examined. The results contributed to a deeper knowledge of the working methods of Portuguese Mannerist regional painters and to the characterization of a drawing style that can be useful for the study of other works attributed to this master.























Paint layers
The painter's palette is made of lead-white, lead-tin yellow (Type I), ochres, vermilion, azurite, smalt, verdigris, charcoal black, ivory black and red lakes made from brazilwood, cochineal, madder and indigo. The pigments were bound in an oil-based medium. Simple pigment mixtures, lighted with lead-white and shaded with black and/or ochre, were used to build volume and shape. Glazing red and green draperies and the use of local undermodelling under the blue draperies are characteristic of the painter’s traditional working methods.  the painter’s exploits and combines a range of different oil painting techniques, such as glazing, scumbling, wet-in-wet or wet-in-dry painting. the painter also uses the imprint of his fingers and pointed tools such as the back end of a brush handle to work the oil paint while still wet. The imprint of a cloth to work the surface of red glazes was found on some of the paintings.  The description of some of these techniques was found on painting treatises from the 16th and 17 th centuries, revealing painting practices that appear to have been widely used.
























Historical Reconstructions
To better understand technical aspects and the behaviour of complex materials within the multi-layered 16th century paint system, reconstructions using the most historically accurate materials were performed in relation to 1) the nature and structure of the grounds and preparatory system; 2) the underdrawing stage; and 3) the use of a fabric to imprint the surface of red glazes.






















The investigation was developed in the context of H. P. Melo PhD thesis.