One of the things I find fascinating about the hobby is when cards turn up with goofy printing errors, overprints, oddball reverses, etc... Or in other words, turn up looking different than how they're supposed to look. The d311 set is my favorite PCL set so I really enjoyed stumbling across this one.
The Van Buren on the left is how the card typically looks. What I'm figuring happened here is the example on the right missed a color pass (yellow) during the original print run. Either that, or the printer ran out of yellow toner altogether. The result is the card on the right which looks a little too blue, and yeah, has that neat looking blue grass.
I believe I remember someone mentioning these to me years ago so I don't believe this sort of a variation is new to the hobby, but it's a fun one nonetheless! This is the first one I've run into, or at least the first one where I was paying enough attention to catch it!
d311vanb.jpg