Plaatdruk papier - Recess - Intaglio paper - Papier stalorytniczy

Already in the late 1940-ies for Polish stamps. All paper used in the first 10 years seems to be uncoated. About 1959 stamp paper with a watermark appears and stays till 1963. In the same period - 1960 - we see the introduction of coated paper. There is no combination of coated paper and watermark. A third factor coming up in the same period is the use of optical brightening agents.

Let's make a table of options:

1. In the early fifties all stamp paper was without watermark, uncoated and without optical brightening agents. / Papier bez znaku wodnego, niepowlekany i bez wybielaczy optycznych (bez WO)
2. From 1959 till 1963 a watermark has been used - no OBA's / Znak wodny , bez WO
3. As above, but with OBA's / Jak wyżej, Znak wodny ale z WO
4. Unwatermarked paper, coated - no OBA's / Bez znaku wodnego, bez WO
5. Unwatermarked paper, coated - but with OBA's / Bez znaku wodnego, ale z WO
   • OBA in coating, not in paper itself [pulp] / WO w warstwie powlekanej, ale nie w masie papierniczej
   • OBA in paper itself [pulp], not in coating / WO w masie papierniczej, ale nie w warstwie powlekanej
   • OBA both in coating and in paper itself [pulp] / WO w warstwie powlekanej i w masie papierniczej

In option 3 the OBA is present in the coating, not in the paper pulp. I'm not quite sure whether options 2 and 6 do exist...

Since I have most of the stamps issued after 1988 because of a subscription I could examine the stamps of that period. After 1969 all stamps printed in recess / intaglio were printed on uncoated paper - apart from the recent period when DLR and Tullis Russell was involved. Options 3 and 4 are farther to be explored...

Recess / Intaglio