Here is a tertiary plate flaw (TM) on the 25 pf value (Mi #50) of the 1949 Berlin "Buildings " series. Michel and the expertiizers rely on the work of Alfred Lippschuetz and others who have continued the study of this series.
Plate flaws of this series listed by Michel are only a small group of the "flaws", because most of the stamps have them. Lippschuetz's work shows all of the constant varieties, while the expertzers and Michel Deutschland-Spezial
catalog list and value only what they judge to be the most important ones.
The plate flaws listed fall into three categories:PM
: "Primary features/flaws are deviations that already occur in the basic cliche. They are repeated ten times in the layout according to the structure of the plate." The primary flaw PM 2 of the 25 pf value occurs at fields 2, 4, 6, 8, 10, 52, 54, 56, 58, and 60 and it is not listed as a PF by Michel.SM
: "Secondary characteristics/flaws are damage that occurs during or after mounting the panels, but before printing begins." There are no secondary flaws for the 25 pf value.TM
: "Tertiary plate flaws are damage to the printing plates that occur during printing." There are 25 different tertiary flaws on the 25 pf value. Michel lists three of them.
This particular PF is Mi 50 PFVIII "damage to the roof of the right tower." It occurs at field 4, with the house printing number (HAN) of the pane unknown. The flaw occurs on stamps with the primary feature/flaw PM 2 (leaf with missing line, shown on second pic).