MUSEUM DESIGN, Sandro Ranellucci, pp.382, 2007
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5.1 NATURAL LIGHTING
5.1.1. Natural lighting in a museum
A properly luminous environment constitutes an essential condition for the appreciation of the collections.
Always under the natural lighting profile, is as important that works and documents related to the light would not be damaged.
Accordingly to their characteristics, the works have actually different sensitivities towards the lighting conditions, the radiation period, the spectral composition of the lighting source in relationship to the presences of visible rays, ultraviolet and infrared rays, as well as towards the heating system.
For this reason, the control and the attenuation of the natural light in the most proper integration of the artificial light are fundamental in the project.
In the past, the museums were particularly based on natural lighting. In many cases, fluorescent lights were applied above a translucent ceiling, in order to obtain the closest condition possible to daylight. In other cases, the previous solution was integrated through the installation of projectors or appliqués at the ceiling. Formally similar systems were adopted when the presence of exhibition spaces above did not allow real skylights. For instance, one was provided with a large grid of metal and glass profiles surmounted by halogen fixtures able to rearrange a situation close to daylight.
Requirements (or limits) of natural lighting in the museum
The more the collections result intensely lit, the better the details are well visible. And yet, symmetrically, the more works and documents are intensely lit, the more they suffer damage at different levels. In reality, according to their material nature, the works experience consequences deriving from the effects of lighting, radiation, light spectral composition as well as heating. In considering an illumination from above, the conformation of the covering could result inclined, oriented in relation to the shed conception; or could be introduced through the façades of the buildings, using more or less conventional glass windows. In the case of natural light incoming from the windows, it will be necessary that they are provided with curtains, more or less mitigating according to the orientations. Their weft will be more or less thick until determining the condition of a shading curtain.
Natural lighting in the Nineteenth century museums until the premises of the Modern
Between 1816 and 1830, Von Klenze designed the Gliptograph museum in Munich. The external light is diffused in every exhibition environment, passing through large openings, such as central oeil-de-boeuves in the domes.
In regards of the Gliptograph museum designed by Canova in Possagno between 1819 and 1833, during the same time of the Munich one, it is possible to find a similar quality of light, interpretable as the luminosity of an artist’s studio. Besides the purely stylistic element, the same light introduced through Schinkel’s enormous windows is to be found in the Museum of Tournai, designed by Horta in 1903, or also later in the Gemeentemuseum of Berlage in the Hauge of 1935. Moreover, in the same New Gallery by Mies van der Rohe (1962-68) are not present other criteria, concerning natural lighting, that cannot be referable to those valid for an artistic studio. In 1958, in the Museum of Western Art in Tokyo, Le Corbusier conceived solutions of specific correspondence of light to the exhibition requirements, both in certain cases highlighting the inner transparency of the building, and in other areas dimming the excessive entrance of the light through brise-soleils. On the covering were adopted other light entrances such as, for example, the pyramidal one in the central area and the double-shed, lateral ones able to determine an effective light dosage. Few years later, following a different direction from Le Corbusier’s alternation of light and shade, Mies reached a different kind of exasperation by introducing inside the totality of natural light. In the Kimbell Museum by Louis Kahn (1967-72), except for the screening through aluminum elements, the works are exposed to a direct, zenithal lighting. In the Van Gogh Museum in Amsterdam, which project was begun by Rietveld in 1953, there was a main use of a succession of windows, to which the diffused luminosity of the ceiling light fixtures was associated.
Natural lighting in installations of the second half of the past century
One of the first solutions for a well studied natural lighting, slightly modified for modern times requirements, is recognizable in the project graphics for the Palace of Capodimonte. It came just after the restoration of the roofing, by the substitution of the previous wooden structures with modern, steel frames. With this integration, were created determined, precious zenithal luminous sources, variable in their effects through the use of different types of lower screenings. In the same solution, just underneath the skylights, have been adopted louvres, limiting the light. Below, a false ceiling hanging through tie-beams was limiting the introduction of light in the real exhibition environment. In correspondence of the opaque, perimetric portion, were predisposed footbridges practicable on the upper part for the inspection of the technical rooms. The real lighting means consisted of inclined stretches perimetric to the central, opaque false ceiling. A grilled surface inclined to the vertical, perimetric walls filtered both the natural light coming through the skylights and the light of the glow tubes and the incandescence sources placed immediately above.
Considering more recent examples, in the vertical windows of the museum of Cologne are used mitigating curtains to dose the entrance of natural light. In the rooms of the new Louvre, installed by Italo Rota, the accesses to the pre-existing windows are narrow and equipped with curtains with vertical rollers. In the Picasso Museum in Paris, at the lower floors and in the basement, until the recent adoption of mitigating curtains, the windows could cause annoying effects of backlight. In the Museum of Castelvecchio, a use of natural light through direct introduction has been adopted by Carlo Scarpa to obtain effects of great variety.
In any case, generally, from any direction the light may come, it is not a good rule that it hits directly the works with strong intensity.
In the case of the Yale Center for British Art (1977) in New Haven, in the rooms and spaces reserved for the circulation, Louis I. Kahn sets up the lighting on a zenithal introduction through skylights in the shape of transparent plastic domes. In correspondence with the exhibition rooms, the skylights are instead filtered by brise-soleils with metal lamellae. Elsewhere the light is dimmed and diffused by panels of plastic material. Underneath the same panels, some projectors on tracks – spotlights in the rooms and downlights in the halls – help to introduce the lighting until the ground floor.
For the MOCA (1986) in Los Angeles, Arata Isozaki designs in the covering transparent pyramids of different dimensions. The biggest one of them creates a showy effect. The other apertures are screened by a succession of pyramids as well.
In the Kimbell Museum (1972) in Forth Worth, according to the fact that the displayed works, all preceding the Twentieth century, were created in daylight, Louis I. Kahn decided to present them in natural light.
For the installations of the second floor of the Cour Carrée at the Louvre (1992), Italo Rota conceived mobile screens between two transparent large windows. Through them, the light, both natural and artificial, looks dosed and controlled. For the Ménil Foundation in Houston (1987), Renzo Piano designs an anti-UV glass window, to which are linked together fixed lamellae of ferrocement painted in white. To them are connected lighting fixtures for the integration of light through artificial fluxes. If in those rooms are displayed works that can be damaged by light, the zenithal lighting is blocked. The shape of the brise-soleil element of the control system is so essential and recognizable in that museum, that it has been adopted even as its symbol.
Another instrument for the introduction of the light in the museum is the shed. It coincides with a consolidated typology, almost traditional, that allows to obtain a diffused light in function of its orientation, aperture angle and characteristics of the reflecting surface. Some shed consist of very vertical glass, as in the Alvar Aalto Museum or in the Museum of Fine Arts in Grenoble.
In the Aalto Museum (1973) in Jyvaskyla, Alvar Aalto treats natural lighting on the basis of sheds with lucid glass oriented towards east, besides the windows. The light comes out reflected and regularly diffused. A complementary lighting of artificial kind is conveyed through fixtures on tracks. The natural light, caught by the sheds, the conical skylights, and the high windows equipped with filters, penetrates in a limitation of the outward view.
In the museum designed by Aldo Rossi in Vassivière, a Contemporary Art Center (1991), the natural lighting comes into the exhibition rooms defined by a wooden roofing through a double row of little, arch shaped windows. In the portion of this museum typologically fitted as a lighthouse, the natural lighting, introduced from above, slides along the inner, slanting curved walls dramatically highlighting the spiral sequence of the metal steps.
In the exhibition room underneath the covering of the Art Museum in Vassivière, as mentioned, the natural lighting comes through several arch shaped openings aligned in the lower part. The result is that of an efficacious evidence of the plastic qualities of possible sculptures, where their surfaces might be emphasized by lights and shadows. On the contrary, natural lighting may not be ideal for possible paintings: a total unilateral source would cause dazzling conditions of backlight.
Regarding the diffused reflection on the vault, besides generating a basic evening lighting, there is the possibility of correcting the dosage of natural lighting.
Natural lighting: recent solutions
In the recent Museum of Contemporary Art in Hamburg, characterized by frequent and large squared windows, all the environments overlook a great central court, covered by a big framed glass with two oblique pitches, from which comes down the direct natural light.
In the Dulwich Picture Gallery, the restoration itself, rigorously adopted, offered the occasion to assign the proper role to the large, opened skylights in the vaults. In the Ludwig Museum in Cologne, the motif of the numerous sheds of the roofing, besides constituting a real solution for a diffused and controlled entrance of light, determines a characterization of the upper profile of the vast building, so strong to assume a value of urban feature.
Switching to the installation of the Burri Museum in the Albizzini Palace, can emerge a consideration on the limits of the use of ancient, residential typologies, or, in any case, of monumental buildings to host works of large dimensions.
Still analizing specific solutions of natural lighting in different museums, can be remembered the role of the circular hole in the vault of each environment of the Museum of San Lorenzo in Genoa, through which Albini obtains the effect of a real natural spotlight, exalting the document underneath.
Another, very particular solution is the one adopted by Scarpa for the entrance of natural lighting in the already mentioned collection of plaster casts in Possagno. The cut of the corner in the volume, a lantern more than a window, allows the determination of an intense light beam, through which the sculptures are lit in a slanting way.
In the East Building of the National Gallery in Washington, among the thick walls covered by white marble of the Peloponnesus, are inserted large windows with sudden angle variations.
The Air and Space Museum is situated at the long Museums Mall in Washington as well. Inside one confronts big blocks, almost without natural light entrances, corresponding to the several functions able to take advantage even of an exclusively artificial lighting, especially alternated with completely transparent surfaces.
In the Museum of Applied Arts in Frankfurt, Meier uses wide windows, methodically squared according to white grids, through which the entrance of a diffused and ample light is determined. For what concerns natural lighting, the shifting out of the window line determines a condition for which the light seems more intense because caught more externally.
The tendency to introversion appears a characteristic that frequently returns in the contemporary museum, connected to the will of eliminating or limiting external view, undoubtedly distracting. It is often associated with a museum typology defined as “court” shaped.
In the Mirò Museum, natural light slides inside the curves of the powerful sheds, reaching in this way softly the paintings on the walls. According to a widely diffused procedure, halogen spotlights are placed inside the sheds directed to curved surface, with the luminous rays downwards as well as spotlights in a symmetrical position directed upwards.
In the Whitney Museum in New York, there are only a couple of openings in the main façades, one per each façade. In addition, from inside, the opening looks used as a backlight frame for a sculpture or for emphasizing its presence by a definitely oblique light beam.
Different kinds of sheds, with a not curved profile, but flat and oblique, are the very numerous ones on the covering of the Museum of Mönchengladbach, with a completely diagonal direction regarding the orthogonality of the walls.
In another area of the same museum, an entirely circular skylight, that passes through the considerable thickness of the horizontal covering of the environment, enlightens with the maximum exaltation of the contrasts of lights and shadows the polished female nudes belonging to a Paolini’s work.
But perhaps the most interesting direction is the one that provides for the entrance of natural light in the museum as an adaptable utilization to the needs. In this sense, a specifically planned and evolved system is the one conceived by Italo Rota for the New Louvre. Underneath a double transparent layer in line with the covering of the building, a succession of white, inclined planes has the task of reflecting the light inside by dimming its direct impact. At the sides of the reflection system, the lighting structure is extended through transparent planes, hiding as well a complementary, artificial lighting system. In other rooms, the parallel direction of the white, slanted blades is substituted by a concluded and gathered system of inclined planes, able to protect the works from the aggressiveness of an invasive and direct diffusion.
Still on the basis of the light sliding on white, inclined planes functions the majority of the control systems of natural lighting. In the attics of the Museum of the Orsay in the old d’Orsay train station, designed by Gae Aulenti (among her collaborators there is also the just mentioned Italo Rota), the entrance of natural light has been mostly maintained direct.
A pure light introduced directly into the museum is appreciated in relationship to works that have been painted on an easel outdoors. For the Impressionists’ painting in the Parisian site, was preferred a condition that displays the changes of the light quality hour by hour, and day by day, in the museum of Houston designed by Renzo Piano.
In this case, the little lamellae of the grid, of the type that in a smaller dimension was adopted with similar function also in the Museum of Capodimonte, transform themselves in the museum in Houston in gigantic, suspended, longitudinal vertebrae.
The experience of dosage of natural lighting undertaken at the Gare d’Orsay continues in the East Wing of the Cour Carrée of the Louvre, where Rota uses a similar system to light the rooms of the French painting. The lighting coming from above is based on a system of small, suspended screens just underneath the transparent skylights. Summarizing, the system adopted by Rota, proceeding from above to below, passes through the transparent surfaces of the skylight on the surface of the little, mobile screens, then on the inclined one at the top of the perimetric walls, and eventually on the paintings, object of the lighting.
In the Museum of the Architecture and of the Arts, designed by Moneo in Stockholm, even from the external profile, the covering elements conceived for the entrance and diffusion of the natural lighting are extremely recognizable.
Characteristics of the transparent surfaces compared to the lighting
A percentage of glare almost close to zero might be a quality planned by the project, as in the case of the crystal of the famous pyramid for the entrance of the Louvre, required from the factory with this quality to reduce to the minimum the sensation of obstruction by the volume in the pre-existing monumental context. In the great room with barrel vault of the Louvre, the reflection system is extended on almost the whole vault. This stratagem that allows a constant entrance, not damaging for the paintings, consists of bringing back the original, geometric conditions of a totality of facets made of inclined planes. Also the Guggenheim Museum in New York in its original version had a specific relationship with natural light, both the one coming from the central lighting, diffused in the well included in the spirals of the visiting course, and the one introduced by the inclined band just above every curved stretch forming the continuous exhibition surface of the museum.
Backlighting conditions
In the National Museum of the French-American Cooperation in the Blerancourt Castle, the paintings receive an indirect light from a wide, continuous slot on the ceiling, diaphragmed by white, slanting lamellae. Along the further edge of the same slot there is a linear succession of artificial lighting fixtures, alternately proper to integrate natural lighting or to substitute it during night condition. Another slot, low, long, horizontal, with its transparent glass cuts the display walls, letting people glimpse the surrounding meadow. The white marble pavement, as consequence of such reflections, becomes whiter and brighter. In the case, instead, of the slot next to the floor, if with a far away sight the perception of the surrounding meadow is caught with a certain dazzling feeling, in a closer observation of the painting, the direct perception of the external light fades out from the visual cone belonging to the painting sight, and therefore this condition becomes bearable.
Solutions for reflected light
Going back to the attics at the Gare d’Orsay and to the particular natural lighting of the works that has been adopted for them, on sunny days, the light penetrates directly on the works. During cloudy days in Paris, it is possible to recognize the moving shadows of the clouds on the canvases. This kind of choice is the consequence of the will of reintroducing those paintings in their original context. To the complete opposite critical opinion belong obviously those that retain necessary a museum fruition in constant quality conditions, apart from the variability of the external conditions.
The role of the alternation of light and shadow seems confirmed in the famous museum of Bilbao. In the Vitra Museum, in the roofing, a skylight captures with its inclined, transparent glass the light, that then is transferred with zenithal direction to the furnishing elements displayed on more levels in the museum environment underneath.
In Basel, in the Museum of the Beyeler Foundation, the composed classicism of the volume designed by Piano shows its coherence with the type of the adopted solution for the introduction of natural lighting. Its result is a direct light, even if filtered, completely homogeneous, constant, natural.
The central oeil-de-boeuf of the Bonnefanten Museum in Maastricht introduces natural light sliding on the inner side of the curving vault. The typology of the lantern, main external element in the characterization of the museum at a urban level, is turned over on the inside to a spatial feature exalted by the light.
In the Picasso Museum, in the Parisian Marais Quarter, for a long period its windows have been maintained without the most trite presence of mitigating curtains, with the result for the visitors of annoying perceptions of the works. Considering the banality compared to the possibility of giving a solution to the problem, it les presume – at least for the period it occured – a will of consciously creating a sort of pre-museum relationship (almost of private collection) between building and work.
In the section of the Galician Center of Contemporary Art in Santiago de Compostela (1988-94), Alvaro Siza communicates a tendency towards concealment about the relationship between architecture and illuminating requirements, typical of the late-modern formulation in museum lighting. Not more displayed as in Le Corbusier’s roofs or in the slots that typologically declared showed on façades, in Siza’s project lanterns and sheds correspond to manifold effective entrances of light.


Allo stato corrente per museologia si intende la disciplina cui compete la responsabilità dell’indagine scientifica, la definizione delle metodologie di studio e ordinamento dei beni culturali mobili, i quali, perduta la collocazione che li inseriva nel contesto d’origine, pervengono al museo.
Nella museografia si identifica invece la disciplina cui compete lo studio metodologico dell’architettura del museo e delle sue componenti. In tal senso essa potrebbe dirsi che sorga nel XVIII secolo. Nella sua costituzione appare implicito il passaggio da conservazione finalizzata ad un uso privatistico al riferimento ad uno strumento di uso sociale generalizzato.
Per rendere didatticamente più efficace la distinzione tra museografia e museologia si potrebbe ricorrere ad un’espressione cara a Minissi, da lui utilizzata per una grande mostra sull’articolazione del museo che si tenne nel Palazzo delle Esposizioni. Il titolo di quella mostra era per l’appunto “Museo perchè, museo come”, alludendo con l’espressione “museo perché“ alla Museologia, e con “Museo come” alla Museografia.
Quanto alla museografia in particolare essa è disciplina di complessa articolazione. Prevalentemente di competenza dell’architetto, ma con competenze composite, le quali potranno avvantaggiarsi sicuramente degli apporti di molte altre figure professionali. Tra le quali potranno essere citate principalmente quelle di carattere psicologico, sociologico, pedagogico, che avranno il compito quanto meno di interpretare la molteplicità dei livelli richiesti dalla diversità delle utenze.
Altrettanto e ancor più auspicabile è un rapporto di stretta collaborazione con gli specialisti delle competenze insite nell’oggetto del museo: l’archeologo, lo storico dell’arte, l’etnologo e così via.
Rispetto a questo genere di apporti l’architetto responsabile dell’allestimento deve porsi nell’atteggiamento d’un interprete, d’un fornitore di soluzioni, di cui manterrà la responsabilità per qualità architettonica generale.
Nei casi in cui fosse il museografo ad assumere un ruolo di decisionismo autonomo ed esclusivo, si verificherebbe un’inaccettabile squilibrio nell’apporto al progetto del museo. In tal caso la struttura architettonica rimarrebbe priva delle necessarie connessioni con i contenuti.
Un simmetrico squilibrio si verificherebbe allorché fosse il museologo a voler far prevalere la sua alta specializzazione, ritenendo di poter limitarsi ad un contenitore indifferenziato o peggio a competenze di teatralità o di scenografia.
Al rischio di tal genere di spaccature nella rivendicazione delle competenze, si aggiunge la condizione degli insegnamenti universitari sia nel nostro paese che a livello internazionale.
Da una parte si evidenziano in tal senso nelle Facoltà di Architettura gli insegnamenti di Allestimento, di per sé troppo mirati al pragmatismo del fare, dall’altra il vuoto sotto questo aspetto nell’ambito delle discipline della conservazione, rimasto tale dopo che rispetto alla componente museografica, nell’insegnamento universitario, sembra si sia preferito indebolire le componenti metodologiche di carattere critico che le vedevano di necessità coesistenti con il restauro.
In una condizione di tal genere appaiono necessari approfondimenti di carattere unitario.
Mantenendo intrecciate tanto le componenti critiche preliminari; che vedono la museografia connessa alle discipline di carattere conservativo, quanto le competenze specialistiche di carattere architettonico, connesse ai contenuti del museo.
In questo senso, in un ruolo di contrasto rispetto alla dicotomia strisciante che insidia il cattere unitario della museografia, al di fuori della condizione degli ordinamenti universitari statali, un ruolo di grande rilievo è stato svolto fino ad oggi dal Centro per la Museologia, nell’Università Internazionale dell’Arte di Firenze, fondato da Carlo Ludovico Raggianti nel 1968. In questo senso è stato concepito questo libro."












