1. Medicine made by dissolving a drug in alcohol.
2. A colouring or dyeing substance; a pigment.

No matter how many you enter, GP surgeries look pretty much the same. It’s as if the NHS has a design department to standardise interiors, prescribing colours for each wall. The playschool primaries, faded pastels and neutral creams encourage patients to cheer up, calm down. Soothe the eyes, so the logic goes, and the body will follow.

In 1921 the American architect William Ludlow published a pioneering article called 'Colour in the Modern Hospital’, in which he argued that judicious use of colour could make patients feel ‘that perhaps the hospital is not such a bad place after all.’ The hospitals of the time were like modern art galleries: every wall was white. White carried overtones of sterility and cleanliness, but more importantly it enabled blood, shit and vomit to be clearly seen. For Ludlow, however, white was ‘negative’: by embodying every colour, it neutralised them all. He associated white with winter, the season of death, and assumed that patients would too. In its place, he proposed a palate inspired by the radiance of nature: ‘soft greens, pale blues, an occasional touch of red’.

Levels of cortisol, the stress hormone, can rise at the sight of red. It’s the colour of headlong passion, supposedly; but it can also make you STOP. Perhaps its stridency derives from haemoglobin, the iron-rich, oxygen-carrying component that lends red blood cells their colour. It makes sense for us to notice when someone is bleeding, or when blood rushes into their cheeks: red can indicate imminent death, or sex. This waiting room floor is closer to rust than blood – darker than plant pots, more ruddy than soil. Mimicked by the carpet of the main consulting room and in the tiles that border the floor of the entrance, it never rises higher than the soles of you feet. (Red is the heaviest colour; it sinks to the floor of the visible spectrum.) Picture this colour on the walls or ceiling and the whole place closes in, starts to feel like the inside of an organ.

William Ludlow argued that, of all possible colours, ‘glorious golden yellow’ was the most beneficial since it evoked the healing power of sunshine, but pick the wrong shade and you’re left with jaundice or bad teeth. Instead of sun we have sky, these cool, unclouded walls. Something to remind incoming patients of open space the moment they pass into the corridor’s enclosure. You might assume this long, branching pathway represents veins, which, seen through the skin, are the body’s blue corridors. But blood isn’t blue, and neither are veins: the closest they ever stray from red is deep maroon. (Kienle et al. put this common misconception to rest in a more or less impenetrable paper, 1996.) Blue is often described as the colour of sadness, but it has to be bruise-blue, shadow-blue, ocean-blue, something dark. This blue belongs to starling’s eggs or Tupperware or the backdrop of nursery murals. Perhaps it isn’t blue at all but turquoise, a species of green.

I can believe that green has therapeutic uses. Green is good enough to eat. Green leaves are healthy, packed with chlorophyll. In the natural world green indicates freshness, growth, recovery. Inscribe this colour on the patient, however, and it becomes a badge of illness: ‘Dude are you OK you’ve gone green.’ In 1914, the San Francisco-based surgeon Harry Sherman developed a ‘spinach green’ colour system to reduce the glare of traditional hospital whites. The colour spread through hospitals like a virus, coating walls, overalls, machines. In this surgery, green is located in details. You have to search for it. The fire exit signs (green is the chromatic opposite of flame); a constellation of pins on a cork board; a stick-man family adrift on a scrap of paper – that’s it. Then you notice the call light for Room 2, lodged in a tiny traffic light above the waiting room entrance. It comes on. The doctor will see you now. Go.

Written by Patrick Langley