Macrophotography of Wide Area Works of Art: a Portable Mechanical Structure for Museum Environments

1 INFN, Laboratori Nazionali di Legnaro, Legnaro (Padova), Italy. 2 Varianti Srl, S.Biagio di Callalta (Treviso), Italy. 3 The “ΔiagArt” Group, INFN, Laboratori Nazionali di Legnaro, Legnaro (Padova), Italy.

4 Dipartimento di Fisica, Università di Padova, Padova, Italy.

INTRODUCTION

Following the increasing popularity of digital photography, in the recent times the “stitching” technique, i.e. the ordered joining of different pictures to obtain a larger image, has gained a great success. This technique, originally applied to 360° panoramic pictures, can be successfully applied to large dimension works of art. Moreover, if applied to macrophotography the technique allows scholars ad restorers to work with continuity on an image with optimal lighting and details comparable with the use of a magnifier lens. Since the large number of pictures one has to deal with, it is mandatory that all the pictures have to be taken in the same geometrical condition of distance and parallelism.

The final goal of this work was to “macro stitch” the P. Piffetti Paliotto (high altar front) of St. Filippo Neri Church in Turin (Fig. 1), in the framework of an analysis programme performed by the LNL “ΔiagArt” group for the diagnosis of artworks.

Fig. 1. Church of St. Filippo Neri in Turin. The Piffetti’s Paliotto mounted on the high altar [1].

Since the Paliotto dimension spans over 10 square meters, a dedicated mechanical structure capable to move both the work of art under the camera and the camera itself with the necessary parallelism had to be planned.

Moreover this mechanical structure had to be transportable and easily mounted for operation in a museum or church environment.

The construction of the structure is presented in this paper, while the photographic session is described elsewhere in this Annual Report.

THE PROJECT PHASE

Starting point of the project were the requirements imposed by the dimension of the artwork to be handled and the weight of the camera and of the illumination system. The widest piece of the Paliotto is 279 × 105 cm. Therefore it was decided to have 3 m for the camera movement and 2 m for the work of art. The weight of the camera system was estimated in about 50 kg. Another constraint to be taken into account was the portability of the structure since it had to be easily dismounted for transportation and remounted for on-site operation.

It was decided to have a fixed platform with a scaffold to hold the camera movement system and rails for a second movable platform to hold the artwork. In figure 2 the first draft of the project is reported.

Fig. 2. Draft design of the system.

3D design computer code was used to have a comprehensive view of overall dimensions, movements, and load distribution. The simulation of both movement and load distribution, extensively performed, allowed finding the best compromise between weight and rigidity of the structure. The calculations also allowed the choice of the type of material to be used: aluminum “Bosh type” bars for the main structure and stainless steel for the camera holding bar.

E. Bissiato1, G. Dalla Costa1, A. Minarello1, A. Alessio2, A. Battistella3, M.C. Buoso3, D. Ceccato3,4, M. De Poli3, D. Zafiropoulos3.

LNL Annual Report 175 Applied, General and Interdisciplinary Physics

Bosh aluminum bars were chosen also for the ease of on-site assembling. Most of the joining elements were standard ones excluding a few, specially designed and machined at LNL Workshop. In figure 3 the definitive scketch of the structure and in figure 4 the structure mounted for final tests are shown.

Fig. 3. Final design of the mechanical structure.

Fig. 4. The structure, holding camera and illumination, during final tests.

the basis of millimeter rulers, but provisions were made for future computer controlled automatic motion.

Minor vibration problems were fixed directly during the final assembling.

CONCLUSIONS

A mechanical structure for the macrophotography of artworks has been designed and assembled at the LNL Mechanical Workshop.

The structure was disassembled and reassembled at the Museo Internazionale delle Arti Applicate Oggi (MIAAO) of Turin (see Fig. 5). The successful photographic session of the Paliotto demonstrated the very good performance of the complete system.

Fig. 5. The structure reassembled at the Museo Internazionale delle Arti Applicate Oggi.

[1] Foto by P. Dell’Aquila from http://www.cultor.org/SFN/Paliotto/index.htm.

The positioning on both axes had to be done by hand on

LNL Annual Report 176 Applied, General and Interdisciplinary Physics