Tomorrow is Remembrance Day. Although I am against Wars and don't particularly encourage the Military, I can't really ignore the date. Sooo...No one in my family ever served during the two World Wars. My Grand Dad, a Frenchman, was recruited as a translator after the Second World War, but only because he lived in the mess that was Europe after fighting was over (and because he was too young to be drafted before that).But my Sweetheart did take the Officer's Course (if that is the right term) when he was in his twenties, my friend Sciath was in the Navy and I have another friend, J., who still is in the Navy. So for them, I salute this days the only way I, your favorite Costumeholic, can.By talking clothes. Military Uniforms to be exact. Costume Militaire, Le Petit Larousse Illustré, 1990Well, there's not all that much I can say: this is not one of my areas of expertise.
What I do know, and thank you Sweetheart for feeding me the info here, is that there was a very important change in uniforms with the First World War. As you may remember from High School History, the Great War was the first to be fought in trenches (instead of on a field).
A century earlier, at the time of the Napoleonic Wars, uniforms were splendid and colourful; the point was to be recognizable on the battlefield. Battles were bloody, but they were disciplined affairs. It was all about courageously running out on the battlefield. During the 19th century, military uniforms were highly decorated, moreover in peace time.
But with the new (deadly) technologies available to armies in the early 1900's, being easy to spot, was no longer desired. Besides, colourful, decorated uniforms for all was way too expensive during this war time. Slowly, throughout the 20th century, Military Battle uniforms (different from Dress uniforms) changed, to blend itself more and more with the environment over time. Cubism, a popular new Art style of the early 20th Century was the inspiration for Camouflage, a print we all know of today and used by the Military all around the world.
That's pretty much all I know. If you would like to see more reference pictures, I suggest you visit the New York Public Library Digital Gallery - Military Uniform. With about 31,770 search results, you should find what you need.
Of course NYPL Digital Gallery is also a great source of pictorial information, whatever you are looking for.