The Use of Technology for the Preservation of Light-Kinetic Art: The Conservation Treatment on Three “Strutturazioni ritmiche” by Gianni Colombo

Maria Cristina Lanza
Electronic Media Review, Volume Six: 2019-2020


The present research focuses on the conservation of light-kinetic art through the restoration of a work by Gianni Colombo. The artwork is composed of polymethyl methacrylate transparent panels intermittently illuminated by an incandescent lighting system, which emphasizes the geometrical patterns made through incisions and cuts on the plastic.  Before the treatment, significant decay restricted the right perception of light effects. The panels could no longer perform their function as optical conductors owing to numerous signs of deterioration caused by mechanical and thermal stresses. Moreover, the lighting systems had partially lost functionality, while the heat generated by the bulbs was the main cause of deterioration of the work.

What should be done when original components of the work cause its degradation? Is the replacement of materials a solution able to preserve the artwork without affecting its authenticity? In kinetic art, the question is still being debated. In this case, a collaboration was necessary between experts in different fields to conduct research to define a project able to reactivate the functionality of the work while respecting the original materials. The solution adopted involved a new LED system and up-to-date technology based on an electronic platform programmed to reproduce the original effects of the work.


The conservation of kinetic works is a challenge owing to the necessity of striking a balance between the preservation of the original materials and the restoration of the functionality of the work. The present research aims at focusing on the methods for the conservation of light-kinetic art through a restoration project for three Strutturazioni ritmiche, by Gianni Colombo (1937–1993).

The restoration, carried out at the Istituto Superiore per la Conservazione e il Restauro (ISCR) of Rome,1 allowed development of different lines of research owing to the heterogeneity of the conservation problems detected regarding the work. A preliminary study was required, leading to conservation treatment both on the plastic panels and on the lighting systems of the three Strutturazioni. In this article, we will focus on the intervention carried out on the electric circuits in order to remove excessive heat production, which was the main cause of deterioration of the work.

In the second half of the last century, many artists assembled kinetic objects by using electromechanical devices, incandescent bulbs, and other components that became obsolete over the years. The use of incandescent light sources often causes various conservation problems due to rapid bulb burnout and to the high heat generated. Furthermore, as in the case of the Strutturazioni ritmiche, artists generally create rudimentary electrical circuits that cause many safety problems.

As we will see, the use of an advanced technology can sometimes offer long-term solutions that are not limited to the replacement of non-functioning elements. In fact, the replacement of the bulbs, carried out over years for the three Strutturazioni, did not prevent the increase of decay of the plastic panels, which were seriously damaged by heat to the point that the Strutturazioni were no longer exhibited for years.

The intervention was carried out with the aim of halting the deterioration process and restoring the functioning of the objects and lighting effects designed by the artist without affecting the authenticity of the work.


The three Strutturazioni were made in 1964 and come from the Galleria Nazionale d’Arte Moderna of Rome (figs. 1a, 1b). They comprise a single work and consist of transparent (poly)methyl-methacrylate (PMMA) panels that are intermittently illuminated by lighting systems, creating optical effects.

Fig. 1. Gianni Colombo, Strutturazioni ritmiche (Strutturazione ritmica, Strutturazione ritmica quadrato pulsante, Strutturazione ritmica cerchio in espansione), 1964. Light–kinetic work; PMMA, aluminum, wood, electric systems. Galleria Nazionale d’Arte Moderna, Rome.  The images show the work turned on (a) and off (b). Photo by A. Rubino.
Fig. 1a.
Fig. 1a. Gianni Colombo, Strutturazioni ritmiche (Strutturazione ritmica, Strutturazione ritmica quadrato pulsante, Strutturazione ritmica cerchio in espansione), 1964. Light–kinetic work; PMMA, aluminum, wood, electric systems. Galleria Nazionale d’Arte Moderna, Rome.  The images show the work turned on (a) and off (b). Photo by A. Rubino.
Fig. 1b.

Gianni Colombo, Strutturazioni ritmiche (Strutturazione ritmica, Strutturazione ritmica quadrato pulsante, Strutturazione ritmica cerchio in espansione), 1964. Light–kinetic work; PMMA, aluminum, wood, electric systems. Galleria Nazionale d’Arte Moderna, Rome. The images show the work turned on (a) and off (b). Photo by A. Rubino.

Gianni Colombo was one of the most important artists of the Kinetic movement in Italy. His artistic production is particularly diversified: we can see kinetic objects whose movement is produced by electromechanical devices, but also artworks whose movement is optical, generated by the intermittence of light, such as the Strutturazioni ritmiche. In these so-called kinetic-visual works, the movement is generated by the viewer’s perception and by the overlapping of the light effects in a dark environment. The interaction with the viewers will become central in subsequent works, in which the artist experiments with creation of real environments and the spectators are completely involved.

The three Strutturazioni were realized with a similar technique. Each object is composed of four PMMA panels vertically inserted, in a parallel sequence, into an aluminum box, inside of which there is a lighting system with four incandescent bulbs controlled by four time switches that produce the intermittence of the light (fig. 2). The artist assembled and fixed all of the elements of the electrical circuit on a wooden panel, installed in the lower part of the base of each of the Strutturazioni. Four wooden elements support the bulbs, which are inserted in ceramic or plastic lamp holders, while metal pins fix to the wooden panel the electric wires that connect the various elements. From the information gathered at the Archive Colomboin Milan, we know that the time switches controlling the intermittence of light are of the same type as Christmas lights, reflecting the strong inclination of the artist to experiment with the most varied materials.

Fig. 2. Lighting system with incandescent bulbs and time switches. Photo by A. Rubino.
Fig. 2. Lighting system with incandescent bulbs and time switches. Photo by A. Rubino.

The work, which looks like a simple design at first sight, is actually the result of a quite complex design process. All of the numerous aluminum elements of the base are assembled in order to convey the light toward the plastic panels and are held together thanks to threaded bars and screws (fig. 3).

Fig. 3. Strutturazione ritmica, side view and internal aluminum structure. Photo by A. Rubino.
Fig. 3. Strutturazione ritmica, side view and internal aluminum structure. Photo by A. Rubino.

The artist originally exploited the physical property of PMMA as optical conductor. In fact, on the PMMA panels, we found linear or circular incisions and quadrangular openings, which are emphasized by the raking light of the electrical systems, overlapping and remaining impressed in the viewer’s perception.


Due to its poor condition, the Strutturazioni have not been exhibited for several years. From a letter by the Archive of the Gallery, dated 1972, we know that the work showed signs of deterioration a few years after its execution, mostly concerning the PMMA panels, which presented a loss of transparency and deformations. However, although at that time Gianni Colombo himself suggested the replacement of the PMMA panels, the Gallery did not agree because, from an ethical point of view, it would not be a substitution but rather a complete remake of the work.

The causes of decay were varied. The main factor was the overheating generated by the incandescent bulbs of the lighting systems, but the materials of the work were also subjected to mechanical stresses produced by the complex assembly system. Moreover, it was possible to observe damages caused by human activities, such as incorrect handling or inadequate treatments during previous restorations. All of these factors caused many deterioration phenomena, both on the plastic panels and on the elements of the supporting base.

The heat emanating from the incandescent bulbs was not compatible with the conservation of the Strutturazioni and caused the worst damage. Both the wooden panels and the aluminum elements showed traces of burning (fig. 4), denoting serious risks not just for the work: the high temperatures had produced evident deformations of the PMMA, mostly located in the lower edges of the panels, where there was flexion and shrinkage of the plastic material. These deformations entailed a lack of parallelism between the panels themselves that, in some cases, lay one on the other (fig. 5).

Fig. 4. Traces of burning on the wooden panel of the base and on a light bulb.
Fig. 4. Traces of burning on the wooden panel of the base and on a light bulb.
Fig. 5. Deformation of the lower part of one of the PMMA panels and lack of parallelism. Photo by A. Rubino.
Fig. 5. Deformation of the lower part of one of the PMMA panels and lack of parallelism. Photo by A. Rubino.

In order to understand the manner of propagation of the heat and temperatures reached by the work when it was turned on, thermographic surveys were carried out by the ISCR physics department. From the results of these investigations, we could see that only 15 minutes after ignition, the aluminum box reached peaks of 50°C, showing a very rapid propagation. The overheating was also sharply increased by the metal elements of the base that, by their nature, are good thermal conductors.

Furthermore, mechanical stresses had caused several losses of different shapes and sizes; some were located in very delicate parts, such as in the lower angular part of the panel, in an anchorage point, undermining the stability of the Strutturazioni. However, there were also smaller losses connected with cracks of various widths. Finally, phenomena of crazing and numerous scratches and abrasions, with different depths, caused a loss of transparency. All of this damage (fig. 6) on the plastic materials was emphasized by the light, together with the patterns of the work, disturbing the optical effects designed by the artist.

Fig. 6. Some of the deterioration phenomena of the PMMA panels. Photos by A. Rubino.
Fig. 6. Some of the deterioration phenomena of the PMMA panels. Photos by A. Rubino.

In examining the three lighting systems, it was observed that only one of the three Strutturazioni had kept the four original time switches still functioning, while the circuit components of the others were subjected to several replacements during previous restorations, mostly concerning the light bulbs, time switches, and electrical wires (fig. 7). Furthermore, the whole apparatus presented serious safety problems because the circuits were not up to standard.

Fig. 7. Replacements of bulbs, electrical wires, and time switches. Photos by A. Rubino.
Fig. 7. Replacements of bulbs, electrical wires, and time switches. Photos by A. Rubino.


The heterogeneity of the conservation problems involving the PMMA panels and electrical circuits required preliminary research in order to treat the deterioration phenomena and restore the functionality of the work. The aim was to stabilize the degradation process and to avoid replacing the original damaged parts (as frequently happens in the restoration of kinetic works), trying above all to ensure the conservation of the PMMA panels, which were entrusted with transmission of the message of the work.

Before and after the intervention, the scientific ISCR departments carried out a series of diagnostic investigations on the Strutturazioni. In addition to the thermographic surveys, already mentioned, measurements of gloss and luminosity values on the plastic materials2 were performed.

We will not deal in detail with the conservation treatment of the plastic material in this article (which will be the subject of a later publication), but we will briefly list the main procedures carried out before focusing on the restoration of the lighting systems.

All treatments on the PMMA panels were carried out with the aim of recovering the stability of the Strutturazioni and reducing the deterioration phenomena that interfered with the viewer’s perception and disturbed the optical effects of the work. For this purpose, the deformations were levelled with an experimental procedure in order to improve the parallelism of the panels and decrease the mechanical stress on the plastic material. For scratches and abrasions, it was decided to apply a selected polishing treatment to lessen only the most disturbing and superficial ones and to obtain an improvement of the gloss values. At the same time, cracks were filled using resins with a suitable Refractive Index, while for losses the direct casting of transparent resin and the creation of inserts in resin and in PMMA was carried out.

The restoration of the lighting systems required a complex study in order to redesign the circuits, since, as we have seen, the excessive heat produced by incandescent bulbs significantly accelerated the deterioration of the PMMA panels. Furthermore, beside the risks of burning of the wooden panels, the heat could cause phenomena of thermal expansion of the metal components of the base, affecting the stability of the work. Finally, it was very important to modify the electrical systems in order to put them in compliance with safety regulations.

In incandescent bulbs, the irradiation of photons is generated by heating a metal filament through a great deal of electrical energy and, consequently, a high voltage. Thus, to eliminate the problem of overheating the work, it was necessary to use a different type of light source. After a careful study of the light effects of the work and following an analysis of the possible interventions to be carried out in collaboration with electrical and Information Technology specialists,3 the decision was made to install a new circuit characterized by lower voltage and with no heat production. The chosen solution was an LED system, which allowed a drastic reduction of the voltage, from 220 V to 12 V, and maintained the original luminosity values and color temperature as the incandescent bulbs (2700 K).   

For each of theStrutturazioni, four LED strips supported by aluminum bars were fixed in alignment with the old light bulbs (fig. 8), largely replaced in past interventions, and thus not original. The length of each strip was calculated proportionally to the number of LEDs and, therefore to the intensity of the light that the incandescent bulbs emitted from their positions. Then, the original electrical wires were disconnected, while the new light sources were connected to an external power supply.

Fig. 8. New system with LED light sources.
Fig. 8. New system with LED light sources.

As for the reproduction of the original intermittence of light, it was initially assumed to be random; however, after some surveys, it was discovered that it was not. A study was carried out on the only one of the Strutturazioni that was still fully functioning and equipped with the original timed switches. Through the creation of a 15-minute video, it was possible to record and determine all of the switching times for each bulb with high precision (accuracy of one-tenth of a second) and to identify a repetitive pattern in the intermittency sequence.

The intermittence of the LEDs was reproduced using an Arduino board, an open-source programmable hardware platform, programmed according to the sequence identified. For this purpose, the data collected were translated into code with specific software (Arduino software IDE) and loaded on the electronic board that, thanks to the connection with four electric switches (relays), allowed the LEDs to be switched on and off in the right order (fig. 9). The programming calculated the effect of overheating of the incandescent bulbs on the intermittence, generating an increase of the frequency in the first minutes after the ignition, before stabilization.

Fig. 9. Arduino board with four relays.
Fig. 9. Arduino board with four relays.

In order to preserve the history of the original lighting system and to guarantee the total reversibility of the intervention, instead of completely replacing the system we decided to create an external circuit that did not entail removing the original components. These were kept intact inside the aluminum base, while the bulbs and the external wiring, already replaced during previous interventions, were removed and stored. Therefore, with the exception of the LED strips, all elements of the new system were placed outside the work inside a small sealed box (fig. 10) positioned along the power cable at a distance of 2.5 m to enable easier management during exhibitions.

Fig. 10. External box with the new power supply and Arduino board.
Fig. 10. External box with the new power supply and Arduino board.


This intervention highlighted the need to address several issues that often arise in the conservation of kinetic art. In this type of contemporary art, there is a great diversity of constituent materials; these are generally industrial products, which suffer from the influence of technological progress and are not always compatible with the conservation of the works. Indeed, as we have seen, sometimes these materials can be the main cause of deterioration. This raises the question of the possibility of replacing the original components in order to ensure the preservation of the work. For this purpose, it can be very useful to carry out investigations on the technique of the work, the intent of the artist, and the components that the artist selected, performing market research on the products. At the same time, it is important to understand to which materials the transmission of the meaning of the work is entrusted to not distort its message. In fact, it is not always possible to carry out a substitution without depriving the work of its essential parts and, therefore, its authenticity. Under these circumstances, the possibility of not intervening and accepting the degradation of work must be evaluated.

Restorers often have to face the necessity of a collaboration between experts in different fields. In this case, the research involved broad interdisciplinary collaboration, which meant the cooperation between contemporary art restorers, experts in glass conservation, technical specialists in electronics and computerization, and specialists in PMMA craftwork. Nevertheless, the conservator-restorer is the figure who has the task of coordinating and leading these various professionals, setting the priorities according the requirements of the work in examination.

Frequently, there are unusual cases of conservation, which involves the need to test new procedures and find innovative solutions. The intervention on the Strutturazioni ritmiche gave us the opportunity to experiment with efficient procedures, enabling restoration of the original perception of the kinetic visual effect, which was essential for understanding the meaning of the work. In this case, the redesign of the lighting systems with the use of LEDs was necessary because it stopped the deterioration of the three Strutturazioni, removing the overheating that would have inevitably continued to damage the PMMA panels. For this purpose, the use of an up-to-date technology permitted generation of the same effect designed by the artist without removing and replacing original components, showing that, in the conservation of kinetic art, the conscious use of advanced technology means can generate solutions capable of preserving the historical witness of the authentic mechanisms.  


The author is very grateful to all members of the working team for their cooperation. As regards to the ISCR, I particularly thank Paola Iazurlo and Maria Elisabetta Prunas for their precious support and collaboration; Fabio Aramini, Giancarlo Sidoti, and Gianfranco Priori for the scientific support and analysis carried out; and Angelo Rubino for the difficult photographic documentation of the work. Special thanks to Fabio Testi, Alessandro Zucca, and Dominik Obuszynski (Zp Elettronica spa) for their essential collaboration in the restoration of the lighting system. Thanks to the Galleria Nazionale d’Arte Moderna of Rome, in particular to Mariastella Margozzi for her help in historical artistic research, and to the restorers Luciana Tozzi and Anna Barbara Cisternino for the information about the conservation history of the work. Finally, I am grateful to Anna Laganà for her useful advice on the conservation of PMMA, and to the Archivio Colombo in Milan, especially to Roberto Casiraghi, for the important information that he provided.


1. This research was conducted pursuant to the thesis for the master’s degree in Conservation and Restoration of Cultural Heritage by Maria Cristina Lanza at the Istituto Superiore per la Conservazione e il Restauro in Rome. Title of the thesis: “Il restauro di un’opera cinevisuale in polimetilmetacrilato: il caso delle tre strutturazioni ritmiche di Gianni Colombo, 2017.” The thesis supervisor is Paola Iazurlo.

2. Diagnostic surveys carried out by Fabio Aramini, ISCR Physics Department.

3. Collaboration for the electric circuits by Zp Elettronica spa; information technology support provided by Fabio Testi.


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Maria Cristina Lanza
Freelance Conservator