As i've seen the same forgery passing on eBay at pretty high prices, i would like to repropose a small tread which i've previosly posted on another forum. I hope someone could find it interesting. Any comment is always welcome.
Polish corp's and Poczta osiedli polskich's issues, as far as i know, have not been subjects to particular forgeries. The only ones which have been forged are just this sheetlets. The reprints were born as sheetlets of bigger size than the original (18 cm vs. 12 cm about), not gummed and not perforated. And they still can be found in this conditions, even on eBay, sometime reproposed as "proof". But just for these characteristics they can be easily identified. Afterwards, the sheetlets have been cut in the right sizes, perforated and gummed to be more similar to the originals.
Honestly, I don't really know if they were born for a fraudolent reason. It wouldn't be clear the reason of such big differences from the original (size/gum/perforation). In my opinion, but I just express my personal opinion, they have been spread in place of the originals just later on, when the interest and the catalog value of the polish corp issues began increasing...
Gum and perforation, anyway, are not so perfect. The sheetlets which was in my hands had a partially blind perforation, while the gum was quite omogeneous and in good conditions. But I also have a set of stamps coming from the same kind of sheetlets where the gum application instead is very poor... That's why these items are sometime sold as hinged, not because they're really hinged, but for the damaged/poor gum.
But without going in a deep exam, it's enough to look at the print: colors are faded respect to the originals, and the drawing less defined and blurred.
Here the three sheetlets:
[Blockierte Grafik: http://img389.imageshack.us/img389/1616/cp3eb4.th.jpg]
[Blockierte Grafik: http://img75.imageshack.us/img75/9827/cp4tl5.th.jpg]
[Blockierte Grafik: http://img53.imageshack.us/img53/7280/cp5fe4.th.jpg]
The three stamps extracted from the sheetlets, originals (i have the certificate, but when you'll see the forgeries, you'll understand there's no need to show it)
[Blockierte Grafik: http://img69.imageshack.us/img69/6170/cp2qr5.th.jpg]
The three fakes
[Blockierte Grafik: http://img103.imageshack.us/img103/4337/cp1yj7.th.jpg]
Hope it could help.