*1.1. Description of the Painting*

The Purísima Concepción painting (see Figure 1) depicts Mary, expectant, her delicate face and smooth skin are accompanied by wide and flowing hair, a pair of ruby earrings set in fine gold hang from her ears, and a pearl necklace hangs from her neck. The Virgin looks towards the devotee, and the hands are fixed in a prayerful position. These, in turn, frame the golden *christogram* on her womb, announcing her future motherhood. His elongated figure, covered with fine cloth, stands on cherubs and the inverted waning moon. (Genesis 3, 15 and Lk 1, 28). Behind her, the reddish mid-afternoon sun peeks out, and at the top, her head is accompanied by a *stellarium*, two angels hold the great imperial crown, composed of the golden circlet of jewels, the crimson reddish lining and three arches. The Holy Spirit witnesses the event, and the blazing sunlight opens the clouds of heaven. In the lower plane, a horizon of warm waters, represented by blue hues and white lights, ends in a continental terrain. On this island firm, the palm, the cypress, and a palm tree appear stoically, accompanied by a lily with a recent shoot and a rose bush with soft and rounded brushstrokes. On the periphery, a simulated frame, with a golden appearance, presents pebbles, shells, and black tendrils made with the point of a round brush.

The visual tradition of this painting had been associated with the characteristics of the art of New Spain which shows variants of the iconography of *Tota Pulchra*, which arrived in America in 16th century, and had continuity almost up to the 18th century [1]. The support of this image is a rectangular panel measuring 258 cm × 165 cm, and is made up of five live-joint planks and three crossbars measuring 11 cm × 165 cm wide each. Tangentially cut and brown in color, the plank and crossbar wood are distinguished by a large presence of knots and a rough surface finish due to the roughing of the material with a possible

hatchet. The reinforcement between crossbars and planks also coincides with the insertion of forging nails through the front and an iron ring located in the upper center of the panel, possibly to hold it to the wall. insertion of forging nails through the front and an iron ring located in the upper center of the panel, possibly to hold it to the wall.

*Heritage* **2021**, *4* FOR PEER REVIEW 3

**Figure 1.** Visible image of Purísima Concepción. Museo Exconvento de Acolman-INAH, México. **Figure 1.** Visible image of Purísima Concepción. Museo Exconvento de Acolman-INAH, México.

Specially in Spain between the 15th and 17th centuries, the size, format and quality of the wood used to support paintings were directly based on an economy controlled by the regulations stipulated in ordinances. The diptych or triptych panels, with dimensions of up to 300 cm high by 250 cm wide, gave rise to altarpieces that, in some cases, reached great monumentality [11,12]. Due to the magnitude of these altarpieces, their execution depended on the collaboration of several artists. The use of wood as a support for paintings lasted during the three centuries of the viceroyalty of New Spain with basically the same construction technology, but during the eighteenth century, its use declined when compared to canvas [13]. Specially in Spain between the 15th and 17th centuries, the size, format and quality of the wood used to support paintings were directly based on an economy controlled by the regulations stipulated in ordinances. The diptych or triptych panels, with dimensions of up to 300 cm high by 250 cm wide, gave rise to altarpieces that, in some cases, reached great monumentality [11,12]. Due to the magnitude of these altarpieces, their execution depended on the collaboration of several artists. The use of wood as a support for paintings lasted during the three centuries of the viceroyalty of New Spain with basically the same construction technology, but during the eighteenth century, its use declined when compared to canvas [13].

### *1.2. Analytical Techniques 1.2. Analytical Techniques*

### 1.2.1. Visible (VIS) and Ultraviolet (UV) Imaging 1.2.1. Visible (VIS) and Ultraviolet (UV) Imaging

The use of VIS and UV fluorescence as complementary imaging techniques provide information regarding the manufacturing process of the artwork. The painting was examined using a lamp UVP mod. B-100AP in long wave (365 nm), and was recorded with a DSLR Nikon D7100, lens NIKKOR 24–120. The use of VIS and UV fluorescence as complementary imaging techniques provide information regarding the manufacturing process of the artwork. The painting was examined using a lamp UVP mod. B-100AP in long wave (365 nm), and was recorded with a DSLR Nikon D7100, lens NIKKOR 24–120.
