Humans are able to see very fine shades of green from drab olives to pale lime. This helps us spot a predator in the day with ease, but helps less in the dark especially if there is no moon. While camouflage breaks up the human shape, colour discernment is a key factor in our survival outdoors, to such an extent that our sense of smell is demoted to a back up third sense after hearing.
Still in the bush, its not wise to wear bright white, especially those nicely optically brightened garments that look cool at a trendy night spot, but wave a challenge in the face of predators, or at very least scare of the more timid types. At the other extreme, I have experienced that downside of driving a black car. During the day in Kruger Park, while slowly coasting along looking for game, a large bird all but flew into the windscreen. Apart from it being an extra 10-15 degrees hotter in the car (Without aircon) I put it down to a bird brain mentality. It was only when shortly afterwards that a large bull elephant nearly walked "Through" our car did I realise the basics of colour physics in action. The Bull may have sensed our movement, but as we were all black, he basically "Saw:" a hole or shadow in the road ahead, and continued boldly on. Mutual surprise, followed by mutual trumpeting in and outside the car, and thankfully zippy acceleration, got us out of a hot spot.
Rescue workers on the other hand will always tell you to wave something white, yellow or bright red to be noticed at sea, in the bush, on a mountain or anywhere else in the wild. There are many tales that a chance glimpse of a colour out of the ordinary helped to save a lost person.
We now see a proliferation of Hazard and Safety gear from stripes on your Nikes to Yellow jackets worn by Police. Even the ragged car guard seems to grow some authority when wearing a Haz jacket.
Next time you are choosing a Fashion Colour, think where you may end up wearing it, and decide if it will be good to be seen, or ghide!