To a bloody war and sickly season - the traditional Thursday toast of the British Navy.
Since I've already written about blue (here and here), a friend suggested I write a post on redder colours, specifically ones named after bloody battles. I only found two: magenta and solferino – both are purplish red colours, perhaps even the same colour. Magenta and Solferino are both towns in Northern Italy that were caught up in the second Italian war of Independence at the same time synthetic dyes were being made from coal tar for the first time. Magenta as a colour name is still in common use, while Solferino was the more important battle. A witness to the battle of Solferino, Henry Dunant, found it so horrible he began a campaign that ultimately resulted in the founding of the Red Cross.
In 1859, Emmanuel Verguin's experiments with aniline dyes (ie the ones from coal tar) resulted in a rich crimson red. He called the colour fuchsine after the fuchsia flower and it was an instant hit. This was a prominent colour of the uniforms at both the battle of Magenta and Solferino, both in June 1859, so I don't know if the colour took these names because of the uniforms or the bloodiness of the battlefields (I've found references both ways). A few years later, the colour's name was once more changed, this time to rosaniline, but magenta is the name that stuck. A arsenic acid oxidation process was required to make this dye causing some of its wearers to be poisoned – leaving magenta even more bloody. (For more details of synthetic dyes 'Mauve' by Simon Garfield is a good read)
If you took a good look at the colour spectrum of light, magenta wouldn't be found. Magenta is considered an extra-spectral colour because it cannot be generated by a single wavelength of light. It is formed in our minds when there are equal parts of blue and red light (in truth colours only exist because our brains perceive them).