I’m currently reading an interesting book called* First Into Nagasaki* by George Weller. It is about Mr.Weller’s experience as the first civilian reporter to visit both Nagasaki and Hiroshima a few days after the Atomic bombings. One interesting claim is that the color white was able to provide protection to both humans and objects from the effects of radiation. He mentions how some Japanese civilians escaped radiation burns solely because they were wearing a white shirt. He also states that he saw two road signs, one blue with white lettering and another right next to it that was white with black lettering. He states that the sign with the blue background was burnt to a crisp, while the one with a white background suffered very little burn damage.
So, can being dressed in all white clothing increase your odds of surviving a nuclear blast?
It’s kinda true, but you wouldn’t want to rely on it.
But first off, let’s be clear, we’re not talking about “radiation burns” here. We are talking about good, old fashioned heat. Clothing colour doesn’t make any difference to radiation burns.
A nuclear explosion emits large amounts of light of all wavelengths. Dark clothes will absorb that light and convert it to heat, eventually bursting into flame. Light clothes will reflect a lot of it, and so not get quite so hot.
But this is only going to be useful in quite a narrow range. Above a certain level, your clothes are gonna catch fire no matter what colour they are. And at those levels your exposed skin is gonna burn through direct exposure. At the other end, dark clothes may get hotter, but they won’t burst into flame and the heat they absorb won’t be enough to cause burns. Then there the fact that if you are close enough to the blast for your clothes to spontaneously ignite, it’s a safe bet that the surrounding buildings and vegetation have also ignited.
In short, almost certainly somebody somewhere was saved from harm because they were wearing white clothing that didn’t ignite. But they would have had to be at exactly the right distance from the explosion, outside, not adjacent to any flammable buildings etc. They would have been rare. All things being equal white clothes are a good idea if you are planning to be near a nuclear explosion, but it’s not really a major consideration.
So a mid-level bomb would kill somebody wearing an SS uniform but spare somebody wearing a klan cloak. This explains why the Germans didn’t pursue atomic bomb research - they realized their racists were more vulnerable than ours.
There are some famous Hiroshima photos where the pattern on a woman’s dress has been printed like a photo negative on her skin by the light flash. Again: more light reflected by white clothing leaving less to burn the skin. It’s a fairly small consideration though.
A theoretically perfectly white garment, one which genuinely reflected light of all wavelengths, would offer excellent protection against an atomic bomb. The problem, of course, is that there is no perfect white, and how white something is in the visible range is a poor predictor of how white it will be in other wavelength ranges. And by the time you get up to the gamma range, everything is pretty much transparent and irrelevant.
along with ‘duck and cover’ having a cotton white sheet was part of the protection procedure. it was during this time that department stores were some of the richest institutions in the country and ‘cotton was king’.
For the curious at home, the best protection against a nuclear explosion is to take into account the drop-off rate of anything which expands in a sphere, and be nowhere the hell near the thing.
Early tower-based atmospheric nuclear testing had some interesting experiments with heat shielding. See Rope trick effect:
So yes, it seems likely that a reflective covering (e.g. a white shirt) could potentially offer some protection against visible wavelengths of light. But it will not provide any protection against blast overpressure, against ionizing radiation (x-ray/gamma), or against longer wavelength photons (microwave/radio wavelengths).
