Colour Perception and Contrast

Light and colour

The human perception of colour is dependent on the pigment colour of objects and on light. Different terms are used when describing colour and include:

Hue: is what is typically referred to as ‘colour’ and is made up of one or more of the primary and secondary colours
Value: is the lightness (‘tint’) or darkness (‘shade’) of a colour
Chroma: is the brilliance or purity of the colour. The primary colours have the brightest chroma and are the most brilliant.

So, when speaking of the contrast between colours, this includes:

Contrast of hue: such as the contrast between red and yellow
Contrast of light and dark: when different tints and shades are next to each other. This includes contrasts such as dark red and pink, which are different values of the same hue
Contrast of cold and warm: when colours with different ‘temperatures’ are placed next to each other. For example, red a ‘warm’ colour and blue a ‘cool’ colour.

Light is a vital part of our perception of colour. The way we perceive colour is a combination of the pigment colour of objects and surfaces in the environment, and the colours in the light that reflect off the objects and surfaces in the environment. Visit the lighting page for more information.

Referenced from Calkins, Margaret P. 2002. “How Colour Throws Light on Design in Dementia Care”. Journal of Dementia Care 10 (4): 20-23.

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The ‘ageing eye’

As people age, many changes occur which affect vision and colour perception. The thickening and yellowing of the lens alters the way colour is perceived. As a result older people may experience:

A reduction in contrast perception ability, resulting in difficulty differentiating between subtle changes in the environment such as carpets and steps
A reduction in the perceived saturation or vividness of colours (chroma). For example reds start to look like pinks.
A reduced ability to discriminate blue colours.

Referenced from McNair D., C. Cunningham, R. Pollock and B. McGuire. 2011. Light and Lighting Design for People with Dementia. Australia: Hammond Press.

Highlight important visual elements

Prominent colour contrast can be used to highlight important objects and add clarity to the environment. A lack of contrast can be used to visually recede elements or to blend in with the surroundings.

For example:

It is useful for the colour of table settings to contrast with the tablecloth or table
Chair upholstery or finishes should contrast with floor
Bathroom fixtures like sinks and toilets should contrast with the bathroom wall and floor (not white toilets against white floors and walls)
Doors can be made less obvious by painting frames and the door the same colour as the wall. Alternatively, to draw attention to the door (such as a toilet door) contrasting paint colour could be used to highlight the door frame or door.

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Colour contrast to define the environment

For people living with dementia, using contrasting colours on floors, walls, skirting boards and benchtops can help define between vertical and horizontal surfaces.

Avoid using linoleum (or similar) floor coverings that run up the side of the wall. This makes it difficult for a person with dementia to distinguish where the floor ends and the wall begins.
In general, ensure that all flooring for areas that lead into each other are homogeneously coloured so that they look continuous. Even if different materials are used on the floor, ensure that the colours are the same or similar so that it is perceived as a continuous level surface. Using highly contrasting coloured materials might be perceived as a change in floor level or mistaken for shadows.
Hanging prominent elements such as wall art or tapestries on the wall can also help to clearly differentiate the walls from the floors.

Colour associations

It is generally agreed that colour associations depend on many personal, cultural and subjective factors; however, there are some underlying consistencies that have been noticed.

Blue

Blues are generally noted to have a calming and restful effect
Often recommended for use in quiet rooms and bedrooms
Cool blues can make rooms appear larger.

Green

Associated with growth and life
It can reduce central nervous system activity and help people feel calm and restful
Similar to other cool colours, it can make rooms appear larger.

Red

Increases brain wave activity and can stimulate the production of adrenalin into the blood stream, and so is recommended for high activity areas and communal spaces where stimulation is required
It can increase the perceived temperature of a room.

Orange

Being a warm colour, it is closely related to red and shares some of its properties. It is also an earth-base colour and like green, it often produces associations with nature and natural environments.

It is important to note that too much use of any particular colour can be overly stimulating (as in the case of a bright red wall) or conversely, too under stimulating (for example a room where everything is blue).

Referenced from Calkins, Margaret P. 2002. “How Colour Throws Light on Design in Dementia Care”. Journal of Dementia Care 10 (4): 20-23.