Before you take it apart, turn it 90º and look at it from that side, take a picture to compare if that helps. Does the one that is darker now look lighter than the others? Assuming all the Steel is from the same bolt, the color difference could simply be caused by the difference in grain (lengthwise vs crosswise cutting). Kona cotton is yarn dyed so there should be no difference at all between front and back, but light does reflect differently depending on the direction of the grain and it can be very noticeable in solids.
Last edited by ghostrider; 12-22-2012 at 08:48 PM.