[Ronnie73]

I'd recommend viewing and comparing the two different ink colors under an USB Microscope if possible. I use the brand Plugable. I know your cards side by side, one does look more purple than black but many faded T206 Old Mill Southern League cards look brown until you either look at the ink close-up or compare it to an actual brown Old Mill. Here's a few pictures of a T206 Blue Ink Old Mill and a T206 Black Ink Old Mill under a microscope, along with a few different shades of Blue to find an exact match as to where the Blue Ink came from. I'm also a big T59 Flags collector, so I understand the different shades one color can have. But I've also noticed that many of those shades match each other when the card backs are broken up into different Factory and Subject numbers. But I still run across a few cards out of thousands that I don't know what color to classify it as. The only way to determine if you have a true color error is to find out where that color came from. After comparing the Blue Old Mill with other cards with Blue Inks, I found an exact match to T206 Piedmont Blue from the same time period of 1909.