There would have been many responses to your post if it took place years ago. Those in the offset trade, chemists and collectors in general who have seen similar examples would have jumped on your post faster than a bat out of hell... but times have changed. My question has always been; "why do we see the dark inlay only on the RES-1..." I kind of agreed back then that it was in the printing process... such as with a new roll of coated stock that maybe later ln caused a chemical reaction with something or other...? I don't know how, tnough.