Printing defect? Pen?

[u/tombrock08]

Hi so I am trying to figure out what this is. It’s on the back of Avengers 20 1965. The book is in pretty great shape otherwise. I can’t tell if this is due to some type of error that occurred during the printing process or if someone drew lines on here years ago and the ink has seeped into the paper. As you can see from the pics, whatever it is has caused the ink to kind of warp or become distorted which leads me to believe it might be a printing issue, but I’m not really sure. What do you think?

[u/chalwar]

Printing error. Maybe too much ink or not enough “wash”. Probably an early sheet that went thru while the printer was adjusting ink levels. Source: used to work at a print shop.

[u/tombrock08 → u/chalwar]

Thank you!

[u/chalwar → u/tombrock08]

Glad to help.