Being a fan of Sharpe, I’ve long wondered why the standard British Army uniform was a ‘redcoat’ – surely the bright colour made the soldiers into obvious targets? I finally discovered the truth behind this (oddly, via a Metafilter comment about the F-22 fighter):
From the modern perspective, the retention of a highly conspicuous colour such as red for active service appears inexplicable, regardless of how striking it may have looked on the parade ground. It should be noted, however, that in the days of the musket (a weapon of limited range and accuracy) and black powder, battle field visibility was quickly obscured by clouds of smoke. Bright colours enhanced morale and provided a means of distinguishing friend from foe without significantly adding risk. Furthermore, the vegetable dyes used until the 19th century would fade over time to a pink or ruddy-brown, so on a long campaign in a hot climate the colour was less conspicuous than the modern scarlet shade would be.