Why Green?

The assistant and I were draping the patient, having painted on the antiseptic, we were putting on the drapes. These are paper nowadays, rather than the more traditional balloon cotton — paper has a lot of advantages — though the green of the cotton is now more of a bluish-green in the paper.

Of course, in countries where the value of the surgeon is properly recognised, all of this is done for you by the hand-maidens. They even hold up the gown for you to walk into it after scrubbing — a rather different way of getting close and personal with someone. But I digress.

“So,” I said, “why are the drapes green?” There was silence. “And what is the physiological reasoning behind the choice of green?” There was an even longer silence.

“Is green not the most restful colour?” was one suggestion.

“Because our eyes are more sensitive to green than any other colour.” Now, this is correct, but I don’t think it’s the right answer here. Actually, I’m not sure if anyone now knows why drapes are green, but it didn’t stop me asking.

“Drapes used to be green-green,” I said, “and now they are this bluish-green. Is this an improvement?”

You really do have to get used to long silences when you ask simple questions.

“I know you know the answer I’m looking for,” I said, “you learned about it in physiology.”

We weren’t getting anywhere. It was as if all physiology had been learned for the examinations, and then forgotten. Perhaps it had been.

“If you look hard at something red for a while, then turn away and look at something white, what happens?” This was akin to telling them the answer.

“You see a sort of red image,” suggested one.

“Red,” I said, rolling my eyes heavenward. “Not red.”

“Don’t you lot remember after-images? After staring at something, and you look away, you see the opposite colour. So, what is the opposite to red?”

A light-bluish green is technically the opposite colour to red. The idea is that after looking at something red — and most peoples’ innards are red — when you look away, perhaps to find an instrument, the after-image will be lost in the colour of the drapes.

Drapes initially seem to have been white — I guess they were something like sheets — though the real reason for the change in colour eludes me so far — and I’m not empirical enough to go trying to find out. Some surgeons in the past used red drapes temporarily when the operation field was contaminated. A bit like ‘red for danger’ and ‘green means safe’. 

Now, where did the idea for colours for danger and safety come from?