About lighting
When considering lighting, it helps to be familiar with some of the commonly used technical terms:
- Colour rendition: is the effect that lighting has on the colour appearance of objects.
- Illuminance: the light that falls on a surface. However the eye sees ‘luminance’.
- Luminance: eye sees ‘luminance’, the technical term for the brightness of a surface. It is dependent on the illuminance on the viewed surfaces, the reflective properties of the surfaces and the position of the observer.
Natural light
Exposure to natural light can assist in general wellbeing and in differentiating between day and night. When designing a new building consider the following:
- How orientation of rooms and windows will provide for the admittance of sun into your home in any season.
- How will light enter the home? Daylight can be brought into an interior through windows, skylights, doors, light pipes and glass blocks.
- Allow for shading where required though the use of window treatments like external sun shading, curtains and blinds. Sheer or lace curtains permit the transmission of light while also providing a little privacy, allowing the person indoors to look out of the window without being observed from outside.
- Maximise the benefit of daylight by keeping curtains open in the daytime. Position seating areas close to open windows so that people can benefit from natural light easily. Being able to see outside to the garden may encourage people to go outdoors.
Artificial lighting
Artificial lighting can be understood in different terms and types. A mix of these types of artificial lighting allows for a range of tasks and needs.
Referenced from: McNair David, Colm Cunningham, Richard Pollock and Brian McGuire. 2011. Light and Lighting Design for People with Dementia. Australia: Hammond Press.
- General lighting: Provides a generally uniform illuminance. Is usually achieved by using a regular array of light fixtures such as down lights.
- Localised lighting: General lights positioned at the task area to provide higher light levels. For example, pendant lights above a kitchen bench.
- Task lighting: Lighting to a small area. Generally used to supplement general or localised lighting. For example, a free standing reading light.
Referenced from: McNair David, Colm Cunningham, Richard Pollock and Brian McGuire. 2011. Light and Lighting Design for People with Dementia. Australia: Hammond Press.
Effective lighting to reduce shadows, glare and reflections
- Artificial lighting indoors should be even to reduce the occurrence of dark shadows. Shadows can be perceived to be objects (or objects may be perceived as shadows) by a person with dementia. Daylight at sunrise or sunset can cause long shadows indoors which some people living with dementia may find disturbing. Shadows of moving trees and branches outside a window can also be distressing. Consider using blackout blinds to effectively block out light when necessary.
- There should be a variety of lighting types so that the light levels can be adjusted during the day (to supplement natural light if necessary) and during the night (to provide bright even lighting throughout the space).
- Minimise glare by considering appropriate types of light fixtures, the number of lights, use of lampshades and appropriate use of surfaces with ‘high diffuse reflectance’ (light spread in all directions).
- Avoid using high gloss finishes or floor surfaces which highlight reflections. A person with dementia may perceive these surfaces as wet or as a mirror.
- Do not use directional spotlights as the main light source as they can cause areas of bright light and glare and at the same time leave other areas in darkness. Spotlights however can be used as task lighting along with other general lighting to supplement the general light levels.
- Avoid sudden changes in light level as shadows can be caused by non uniform lighting. Instead, ensure transition lighting is installed between well-lit areas and less well-lit areas.
- Uplights directed towards a matte painted ceiling will bounce off it and fill the room with diffused and even lighting.
Referenced from: McNair David, Colm Cunningham, Richard Pollock and Brian McGuire. 2011. Light and Lighting Design for People with Dementia. Australia: Hammond Press.
Light and colour
- Use light fixtures with good colour rendering (CRI) to ensure that the night time colour of objects is similar to the daytime colour.
- Dark colours absorb light, maximise the dispersion of natural or artificial light by using light colours especially on large non-gloss surfaces such as walls and ceilings.
- Use tinted glass windows and window treatments specifically designed to reduce glare. However be mindful that colourful glass such as blue toned window glass will filter the light coming into the interior, therefore altering the perceived colour of all the objects and surfaces.
Staff and lighting
Train staff about lighting to ensure they know the benefits of lighting in reducing falls, assisting orientation and positively affecting mood, and when to turn the lights off to save power.
Flexible lighting
Older people, including those with dementia need increased light levels. A person-centred approach to design will always include the use of flexible lighting levels to accommodate any specific individual needs and to minimise power use.
- In corridors and sitting areas consider installing lights controlled by a conventional switch and others by passive infrared sensors which turn the lights on when the space is occupied.
- Automatic switches can be installed to turn off lights when there is sufficient daylight in the space, yet can be overridden in the instance of an overcast sky.
- Timers can be set to turn on/off at a specified time. For example, garden lights set to turn on automatically in the early evening.
- Always ensure that lighting controls are easily identifiable for the person to use. For example, a coloured backplate behind a light switch may make it easier to identify on a white wall. Ensure switches for a table top reading light are positioned near the lampshade or base rather than controlled by the switch at the wall.
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