The Horizon Bleu always struck me as a strange choice of color, too. At first glance, it seems unlikely to be a wise choice for low visibility. In color photos (what few originals exist) and of re-enactors, I am always jarred by how the horizon bleu sticks out, kind of an affront to the whole scene. The reality is that the blue would fade and dirty up to the point where it was almost as good as anything else in the trenches and actually was quite effective under low visibility situations such as smoke, gas, mist/fog/snow, etc. There are also written accounts on how morale amongst tired or reteating troops could be raised by the sight of the clean horizon bleu uniforms coming up as reinforcements. Still, the French did supply khaki versions of their uniforms to their colonial troops as well as the Foreign Legion. These must have been better, low visibility wise. Eventually, the French Army must have thought it was better, too, because during the inter-war years they did switch the regular army to their khaki uniforms and away from the blue for the next war. -- Al