Perforations on Scandinavian stamps suffered in the early period of classical stamps, with the production of the stamps as a manual process. The use of manual labour was the cheapest way to produce the stamps, since the volumes were not high enough to invest in more advanced equipment. In the 1860s in Norway they used handpressed bookprint production and a manual comb-perforation machine, imported from England. The result was not always perfect.
During the printing, several guiding holes were positioned on the sheet above and below the actual print. The sheets were then added glue using a brush and set into shelves for drying.
Before perforation of the sheets, they had to be pressed flat since both the print and the glue added humidity to the paper, making them crease.
Using the small guiding holes, approximately five to seven sheets were stacked together and inserted into the perforation machine.
Using handpower, the metal comb perforated the sheets from the top towards the bottom of the sheet. The comb perforated a single row on both sides and on the top at once, and then moved the sheets one row, readying for the next row-perforation.
The perforation machine had to be adjusted during the perforation process. Studying sheets from this period, we find that they had to readjust the placement of the sheets, often twice.
The result of this process is that we find several stamps with perforation variations. Below are some of the variations that occurred:
Since the machine did not feed the machine perfectly, we find stamps where you may see parts of the neighbour stamp. This skewed perforation may occur both vertical and horisontal. Horisontally the addition of fluids and the drying of the stamps could make the sheet shrink a little, making the vertical placement not fit the perforation combs perfectly, This error would expand across the sheet, and could make the neighbour stamp visible.
When the insertion of the sheets were adjusted in the perforation machine, both so called “long” stamps and “short” stamps could be created, depending on the adjustment. Long stamps have a large gap between the previous comb-perforation row and the new row. This creates broad perforation at the lower part of the stamps.
Short stamps are similarly made, but where the sheets were adjusted back a small step.
Thin paper and perforation.
Some stamps, like these 4-skilling posthorn stamps from 1870s, show oddities of torn perforation on the bottom/top of the stamps. The left one even has a skewed perforation.
Such rough perforation may have happened through adding too many sheets at once in the pile to be perforated, making the perforation needles tear the paper. This 4 skilling issue had quite thin paper that would be more suspect to rough treatment. Another explanation for this variation is a double perforation, where the comb was adjusted a single perforation hole vertically, and then pushed through the sheets again. This would make a double line of holes on the top of the stamp.
Some times you find stamps with double perforation where the perforation comb was reapplied a second time but slightly away from the first. This may create what is called “diamond-perforation”. Such perforations vary depending on how much the comb was adjusted before reapplied to perforating the sheets.
These different perforation variations shows that a stamp that look damaged, might be just a result of the printing process and not by badly storage during the 150 years its been in different books, folders or boxes.