In dyeing, there are the concepts of color fast and light fast. Meaning, how deep and long color lasted, and how fast or slow color resisted UV light fading or breakdown. Vegetable dye stuffs were notorious for not being color and light fast- some more than others. Aniline dyestuffs helped on both counts.
But even aniline is not 100 percent fast, as we see aniline navy blue woolen coats turn purple.
From John Wedeward, and his site, is a sampling of original blouses:
In gleichem Schritt und Tritt, Curt Schmidt
Not a real Civil War reenactor, I only portray one on boards and fora.
I do not portray a Civil War soldier, I merely interpret one.