3D Technologies

Figure 2: NRC's Luc Cournoyer (right) positions the scanner in front of the painting while a member of the Centre de Recherche et Restauration des Musées de France (C2RMF) staff (left) monitors the operation.

Each step in the scanning process was carefully designed and precautions were taken to ensure no damage occurred to the painting.

Figure 3: The laser scanner is a non-contact optical measuring system that acquires successive 4 cm wide bands (as shown by the bluish line generated by a low power laser) across the surface of the painting.

A complete 3-D image is obtained by moving the laser scanner over the entire painting. Each band was subsequently merged by software to create a full 3-D digital model of the Mona Lisa.

Figure 4: NRC Scientist and Technical Lead François Blais configures the laser scanner during digitization of the reverse of the painting.

The entire surface of the painting was scanned – obverse, rear and edges – to create a complete high-resolution 3-D digital model of the painting.

Figure 5: While scanning the edges of the painting, NRC's John Taylor noted surface features visible to the eye. This facilitated a comparison of actual surface features with those recorded by the scanner.

Figure 6: NRC scientist Marc Rioux examines the virtual 3-D model of the painting using a multi-resolution display system also developed at NRC.

3-D display systems enable interactive high-resolution displays of museum objects for the general public, as well as for detailed examination and study by museum professionals.

Figure 7: A color-coded elevation level contour map, similar to a topographical map, illustrates an accurate record of the exact overall shape of the poplar panel.

The graduation between each contour line corresponds to a change in elevation of 0.50 mm with the red lines the highest or most elevated areas and the blue-green lines the lowest. This figure illustrates that the panel has a longitudinal convex curvature due to warping which is most pronounced in the area of the left shoulder.

Figure 8: Similar to Figure 7, the overall shape of the panel is represented in this color-coded shape image. The region in red is more elevated than the lower blue and purple areas.

Painted between 1503 and 1506 on a poplar wood panel, the panel has warped and distorted with time. A color-coded shape image clearly shows this warping effect; the difference between the red and blue represents a warping of 12 mm of the wood panel.

Figure 9: A synthetic shaded image of the painting with the color removed enables the three-dimensional surface relief features of the Mona Lisa to be examined in greater detail.

This image shows that much of the surface relief on the painting is due to the wood grain structure – only a faint outline of the thinly painted composition is visible. In addition, the 11 cm vertical split in the panel above the head is visible, as are areas of previous restorations on the left and right elbows.

Figure 10: The NRC team, from left to right: J.-Angelo Beraldin, John Taylor, Michel Picard, François Blais, Luc Cournoyer, Louis Borgeat, and Marc Rioux; not in the picture Guy Godin, Louis-Guy Dicaire, Philippe Massicotte and Jacques Domey.

Figure 11: This is a snapshot of the high resolution 3D model that was constructed from the data acquired by the 3D color laser scanner. A 3D animation of the painting, obverse and reverse, demonstrates fine details of the findings and results of the study.