Color can sway our mood, alter our emotional perception, and affect our productivity. Colors can also elicit specific responses—red can provoke sexual drive or create a feeling of intimidation; blue can stoke intellectual abilities and mental faculties and affect sleep urge patterns. Colors have other perceptual properties too; for example, certain colors give a false sense of increased space, a phenomenon often exploited in architecture and design.[2,3]
For a number of physical, physiological, and psychological reasons, the most appropriate color for a hospital environment is green. It is the predominant color of hospital textiles and fabrics,[4,5] including sheets, coverings, towels, cases, patient’s clothing, coats, aprons, scrubs, gowns, drapes, furniture covers, curtains, and partitions.[6,7] How did this come to be?
White is the most reflective color, and in 1914 American surgeon Dr Harry Sherman realized that white surfaces could result in a disturbingly intense glare under the bright illumination typically required during surgical and oral procedures. This glare, heightened due to the development of brighter, focused lighting systems, adversely affected his ability to discern anatomical structures. As a result, he created a spinach-green operating theatre (green being the complementary color to red in the traditional RYB color model), with all walls and textiles the same color. This enabled medical staff to easily spot traces of blood on those surfaces, as well as to focus on the details and fine features of wounds.[8,9]
Green being opposite to red on the color wheel helps physicians in two other ways. Prolonged focus on one color can result in lingering pseudo-negative afterimages of its complementary color once the gaze is shifted away from the subject of focus. This occurs because ocular pathways for a color become fatigued due to prolonged stimulation and all other pathways continue to work normally.[10,11] During medical procedures, physicians frequently need to focus on wounds, openings, and interior tissue, most of which appear vividly red. Blinking or shifting focus results in green floaters or ghosts, afterimages of the red subject in its complementary color. These potentially distracting green afterimages blend with green surroundings better than with any other color. Secondly, after prolonged viewing of one color, the eye becomes desensitized to it. Sustained focus on a patient’s bloody body parts compromises ocular acuity as the color appears to fade, rendering medical staff incapable of discerning its nuances and performing medical procedure optimally. The fading is an expression of the body’s general tendency to become desensitized to any unvarying sensory stimulus.[12,13] Green surroundings allow medical staff to quickly switch their stimulus before it saturates the red color pathway.
We are evolutionarily hardwired to increase our alertness and vigilance upon seeing red, it being the color of blood, whether of prey, predator, or self.[1,14,15] Blue stimulates thought and intellect, and makes it difficult to pacify, placate, or tranquilize a patient. Green tends to placate and pacify the viewer.[16-19] Evolutionarily the color became associated with plentiful availability of food and water as early humans would find fruits, roots, prey, and water in lush green areas. In fact, human ocular perception is most attuned to the color green, and it therefore exerts a relaxing, soothing effect on the observer. For this reason, in a medical setting green is likely to help ease a patient into a more calm state, which is beneficial when carrying out a medical procedure.
Indira Gandhi National Open University
New Delhi, India
1. Elliot AJ. Color and psychological functioning: A review of theoretical and empirical work. Front Psychol 2015;6:368.
2. Savavibool N, Moorapun C. Effects of colour, area, and height on space perception. Environ-Behav Proc J 2017;2:351.
3. Koenderink J, van Doorn A, Albertazzi L, Wagemans J. Hue contrast and the sense of space. Iperception 2015;6:67-85.
4. Color in hospital rooms. Can Med Assoc J 1945;52:104.
5. Pantalony D. The color of medicine. CMAJ 2009;181:402-403.
6. Sehulster L, Chinn RY. Guidelines for environmental infection control in health-care facilities. Recommendations of CDC and the Healthcare Infection Control Practices Advisory Committee (HICPAC). MMWR Recomm Rep 2003;52:1-42.
7. Andersen BM. Hospital textiles. In: Prevention and control of infections in hospitals. Springer International Publishing; 2019.
8. Sherman HM. The green operating room at St. Luke’s Hospital. Cal State J Med 1914;12:181-183.
9. Green-Armytage P. Complementary colors. In: Encyclopedia of color science and technology. New York, NY: Springer; 2016.
10. Barber TX. Hypnotically hallucinated colors and their negative after-images. Am J Psychol 1964;77:313-318.
11. Erickson MH, Erickson EM. The hypnotic induction of hallucinatory color vision followed by pseudo-negative after-images. J Exp Psychol 1938;22:581-588.
12. Poletti M, Rucci M. Eye movements under various conditions of image fading. J Vis 2010;10:6.1-18.
13. Clowes MB. A note on color discrimination under conditions of retinal image constraint. Optom Wkly 1962;9:65-68.
14. Association for Psychological Science. Stop on red: The effects of color may lie deep in evolution. ScienceDaily. Accessed 25 August 2020. www.sciencedaily.com/releases/2011/06/110608123002.htm.
15. Mehta R, Zhu R. Blue or red? Exploring the effect of color on cognitive task performances. Science 2009;323:1226-1229.
16. Briki W, Majed L. Adaptive effects of seeing green environment on psychophysiological parameters when walking or running. Front Psychol 2019;10:252.
17. Clay RA. Green is good for you. American Psychological Association. Accessed 25 August 2020. www.apa.org/monitor/apr01/greengood.
18. Jalil NAb, Yunus RM, Said NS. Environmental colour impact upon human behaviour: A review. Procedia - Soc Behav Sci 2012;35:54-62.
19. Nakshian JS. The effects of red and green surroundings on behavior. J Gen Psychol 1964;70:143-161.
20. Dutton D. Aesthetics and evolutionary psychology. In: The Oxford handbook of aesthetics. Oxford University Press; 2009.
This post has been peer reviewed by the BCMJ Editorial Board.