Recently, I have seen a few notes with black vertical lines printed on the backs. These lines are not solid, but instead, appear to be made of random dots. See the image below for an example. Obviously, this is not a major error if it is an error at all.
The lines are very straight, so I think they were made by machine. My hunch is that they are created by the machinery used by the printers, machinery that comes into contact with every sheet when sheets are given their serial numbers. A small amount of black ink used to make the serial number accidently gets onto other parts of the machinery that comes into contact with the sheets, and thus these patterns are created.
Someone listed a series of error notes in the Trading post not that long ago, and these notes had a series of black rectangles instead of dots printed on them. Could this be the same or similar type of error? I can't find the original post... must have been taken down or I forgot to take my Geritol today.
If anyone else has seen Journey series notes with vertical lines or other strange markings on the back (like the note below), please post the serial number, position numbers, and if you can't post a picture, describe the markings as best as possible. It would be interesting to see if these errors are prone to certain positions on the sheets.
The note below is $10 BTS 2516752 56/74 (position H-2 A-1 (based on latest info) )
{http://img255.imageshack.us/img255/201/btserror.jpg:http://img255.imageshack.us/img255/201/btserror.th.jpg}
[edit] Images moved to ImageShack - mmars [/edit]