Overprint printing process

I was looking at the 1918 semi-postals and I am wondering how a pair of stamps can have one completely normal overprinted stamp and the one next to it can have an normal overprint and an inverted overprint.  Does anyone know how the overprints were applied or can anyone explain how the overprinting process worked for these stamps?



  • All I know is that the three parts of the overprint were done in three separate runs. If a sheet would be put into the press upside down for one run and if the opposite margins were of very uneven size the resulting inverted (part-)overprint might be shifted by one column or row, leaving one strip of stamps unaffected. Another run with the correct orientation would produce such pairs. Just one possibility. Another one is they overprinted half sheets, like they did in Liberia with the 1923 to 1927 issues. Then these pairs would occur in the middle of the sheet and must come without margin.
    Anyway, Perkins Bacon must have had an excess of stamps to experiment with, and it looks like they experimented a lot - the work of apprentices? I believe most of these errors are actually printers waste that for some reason wasn't destroyed and came on the marked when the company went out of business (around 1935).
    I must admit that I do not recall having seen such a pair. If you have a picture could you please post it here?
  • Hi Manfred,

    Thanks for the info!  I can see how you could get multiple variations by running the stamps through for three different overprints, especially if they are doing half sheets.  One example that I was referring to is in the Jan-Mar 2011 LPS Journal, p. 8 (Shoemaker p. 4).  It shows a 2c block of 4 where the bottom two stamps are normal but the next two have double "two cent" overprints, one of which is inverted.

Sign In or Register to comment.