In Part 1, we discussed the importance of colour in healthcare environments and how colour influences mood and emotions. In Part 2, we are delving deeper into the nature and perception of colour. You can read Part 1 here:

How we perceive colour

When viewing perception of colour, different characteristics of light sources, human responses to light and colour psychologically and physiologically, and individual differences were considered. The significance of colour in the healthcare environment was described and different areas in which colour can impact healthcare outcomes were identified. According to the precedents, colour contributes to improving outcomes in the healthcare environment.

Nature of colour

Colour is a part of the perception process and is carried to us from our surroundings according to the wavelength differences of light. The perception of colour is a complicated process that involves light source attributes, the texture of surfaces and neurological interpretations. As the light reflects off surfaces, the eye perceives the transmission via an electrochemical response that is interpreted and translated into colour within the brain.

The perception of colour depends on light source characteristics such as Spectral Energy Distribution (SED), the Colour Rendering Index (CRI), and colour temperature; material characteristics such as the Light Reflectance Value (LRV); and the psychological and physiological characteristics, including but not limited to culture, age and visual acuity of the individuals using the space. 

Special Energy Distribution

Special Energy Distribution (SED) is the amount of power from the light source in each colour band or spectral region. It explains the difference between light from a standard fluorescent lamp and natural light, and the way light changes the colours of objects that reflect. 

Emited light spectrum determines CRI

Colour Rendering Index (CRI)

Colour Rendering Index is a measure of the degree of colour shift that objects undergo when illuminated by the light source as compared with those same objects when illuminated by a reference source of comparable colour temperatures.

Light Reflectance Value (LRV)

Light Reflectance Value is the total quantity of visible and useable light reflected by a surface in all directions and at all wavelengths when illuminated by a light source.  LRV is a measurement indicating how much light a colour reflects, and how much it absorbs.

Colour temperature

The temperature of colour is measured in Kelvin Degrees. Colour temperature of a light source is the absolute temperature of a blackbody radiator having a chromaticity equal to that of the light source.

Human responses to colour

Numerous studies have found variations in colour preference across age, gender and culture, and even age differences in colour preferences. Preferences and emotional associations related to colour can be influenced by brightness or saturation.

Saturation is more important than hue in terms of people’s perception of which colour is more calming or exciting. Additional variables included types of light sources or background colours, the effect of context and cultural factors; the effects of the three dimensions of colour – hue, brightness (tint) and saturation (chroma) – and affective value. There are linear relationships between affective value and both brightness and saturation when the hue remains constant. With a constant hue people, prefer lighter and more saturated colours to darker and less saturated.

Design implications for colour in healthcare design

The contribution of the healthcare environment to human well-being has not been fully quantified, but many researchers have investigated the relationships between the built environment and human health using psychological and physiological indicators of wellness such as measures of stress, mood, productivity or cognitive performance.

Undoubtedly, healthcare environments should be friendly, therapeutic and promote the healing process. Colour and light affect patient recovery rates, improving the quality and overall experience of patients, staff and visitors.

Colour can contribute to:

  • Reduce medical errors
  • Promote a sense of well-being
  • Reduce stress
  • Improve patients’ sleep and circadian rhythm
  • Reduce the length of hospital stay
  • Improve spatial disorientation and wayfinding
  • Increase patient satisfaction
  • Increase staff morale and productivity

Full acknowledgement and thanks go to;; for the information in this editorial.

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