Each museum lighting design project contains its own philosophy, history, pathway, suggestions leading to the development of a concept, with the aim of always finding non-invasive solutions for the exhibition space, in agreement with the other professional figures and the client. The design of art gallery lighting has the function of making spaces, volumes, and surfaces visible and emphasizing the architecture. We must always consider that there are indicative illuminations for the good conservation of objects. For example, some materials are extremely sensitive to light, including silks, fabrics in general, works of art on paper, leather, and feathers; moderately light-sensitive materials include oil paintings and frescoes; materials that are less sensitive to light include metal, stone, ceramic and glass.

The project research should push for the choice of the most performing optical solutions for the subject or place to be illuminated, which best meet the architectural requirements imposed by the environmental and structural constraints. Especially in places of worship, which are sometimes actual museums, increasingly often we can find devices limiting the duration or illumination on works of art, such as for the works of Tintoretto, in the Church of San Rocco in Venice. The presence of an automatic brightness regulator with a timed device is important to avoid repeated thermal shocks and sudden variations in luminance. Not forgetting the activities that will take place within the space.

We are confronted with an existing space, thus determining the design choices. As in temporary installations, art gallery lighting will be influenced by the duration of the exhibition. The duration and space of the exhibition will determine the characteristics of the design choices. Often, especially in exhibition areas such as Palazzo Reale in Milan, the existing lamps are used with the integration of some equipment, deemed necessary for the purpose of the project. Another curious fact is that temporary exhibitions, on some occasions, are made in environments that are not spaces intended for the exhibition of works but are special locations, such as the exhibition of the work of artist Emilio Isgrò in a bank vault and in the home of Alessandro Manzoni in Milan. In this case, it is the work that must be inserted in the context, as well as the lighting.

Permanent Exhibition │ Museum Lighting Design

An example of a permanent exhibition is the "The Months Hall" project, Palazzo Schifanoia in Ferrara. In this case, being a space with many constraints dictated by the superintendence of cultural heritage, the designer has created a lighting system that is non-invasive and harmonizes with the existing architecture, thus not altering ceilings and walls, which cannot be touched. The lighting system uses a single, specially designed luminaire: an 85 cm high titanium column with rectangular base houses the LED sources with built-in optics. The 28 columns are arranged around the hall, connected to each other by the power cord that gives visual unity and serves as a boundary for the public.

Art gallery lighting is often a search for the best mediation between conflicting needs. The lighting design in a building of great prestige, which houses important works, is an emblematic example from this point of view. The lighting needs of the two institutional uses of a museum — exhibiting and preserving — are in contrast. While a complete appreciation of the work requires a certain amount of light, the conservation requirements impose great caution and moderation, to best limit the degradation that incorrect lighting can cause. The requirements of architectural lighting, therefore of the container building, are in contrast with those of the exhibition lighting for the works, the content.

Finally, the demands of modern, efficient and economic management are in contrast with those of an optimal rendering of the exhibited works: the lamps with the best color rendering may be penalizing in terms of energy. The balance of a good museum lighting design project, therefore, lies in the search for solutions that best meet all the needs, without compromise, which, in an attempt to solve, leave some needs unfulfilled. Lately, the mediation between conflicting needs is often at the center of the development of a lighting project.

Temporary Exhibition │ Museum Lighting Design

An example of a temporary exhibition is the exhibition "Gae Aulenti. Objects and spaces" at the Triennale Design Museum in Milan. During the design of the lighting project, the lighting designer has to deal with the curator of the exhibition and with the concept of the exhibition itinerary. The curator is an important figure because he or she has the role of conceiving, locating and presenting the works according to the message of the original project desired by the artist.

Temporary settings are characterized by structures that are not always definitive and must meet all the technical requirements. Each set-up is tailor-made for the single exhibition. Therefore, it is not always interchangeable with other exhibitions, even if, in reality, many always use the same type of lighting — projectors on tracks, for example — for several exhibitions with different themes. The lighting project can be interfaced with the latest multimedia technologies, which allow the visitor to have an emotional experience, often involving all the senses— from sight, touch, and smell, to physical interaction with the work.

Open-Air Exhibition │ Museum Lighting Design

An example of an open-air exhibition is that of the "Imperial Forums" in Rome. The entire archaeological area of the Imperial Forum Palatine is an integral part of the urban fabric. Some stations are installed outside the archaeological area with groups of projectors with controlled optics, high color rendering sources, and high efficiency. The Via Sacra project foresees a new conception of the hurdle that will support the electrical distribution and have integrated a lighting system with LED luminaires.

During the development, the project must take into account the parameters imposed by the regulations, which vary from the material that makes up the individual work, since we must not forget that the quality of light is important. With its radiation, whether artificial or natural, it is also one of the main causes of the degradation process to which all cultural heritage items are, to varying degrees, inexorably exposed. It is thus essential to plan art gallery lighting well so that the cultural heritage is safeguarded, while at the same time enabling full enjoyment of the work of art.