Just a little thing !
Do not forget some realities, the coloring agents used for the uniforms were natural (coming from plants or minerals), the soldier never wash its uniform, but for the old Guard, they always fight (in the battles) with their "Grand Uniforme", ceremonial uniform, kept in the backpack during walking.
Also, blue of the uniform of the old Guard was darkened, the troops of the artillery of the navy having been confused with the regiments of the old guard.