The building illustrates its purpose as an art gallery with two principal elements – walls for display and reflectors to control natural light. These devices, visible inside and out, are employed universally throughout the building to capture Canberra’s unique light.

The clarity of planning – with all public spaces on one level – is ideal. Despite the simplicity of the plan, the National Portrait Gallery creates a rich visitor experience and adds a variety of new public and civic spaces to the galleries and visitor facilities that are unique to Canberra. Within the 12 metre module defined by the concrete walls, various arrangements of mobile display walls create a flexible range of exhibition spaces.

Intimately scaled circulation galleries run between the primary bays and counterpoint the light, airy character of the main galleries and illustrate the crafting of the concrete, timber and other materials. These spaces pace the visitor experience and provide rest and information access points. Unlike many galleries, views in and out of the building are important design strategies to connect visitors to the landscape and passers-by and vice versa, including at night.

Linear plantrooms below these spaces enable energy efficient servicing and maintenance without compromising gallery security. Elsewhere, opportunities for environmentally sustainable strategies such as mixed-mode ventilation, utilisation of the building’s thermal mass, energy efficient plant and rainwater re-use are integrated.

All spaces enjoy controlled natural light from translucent glazed clerestory windows, significantly reducing reliance on artificial lighting. Within the galleries a simple blind system enables control of light levels down to 50 lux for delicate works on paper.

The design is inspired by the Vitruvian notion that the proportion of a building should correspond to that of a person. This is particularly relevant to a building for portraiture and for the scale of works in the collection. The building’s siting in the landscape and relationship to its neighbours, its external form, the internal spaces and the individual components and details are all based on the golden section, a unique proportional relationship that describes a part’s proportion to the whole – creating a harmonious relationship between the visitor, space, material, light and art.