½V incorporated panes

 

Recently I was asked "why panes from early stitched booklets with the ½V cut were so expensive?"  

I had to admit that I did not know the answer to the question but I too have often pondered on the same question so I did a little research.

Here are my findings.

Two different perforators were used : These were known as Comb No.1 and Comb No.1a. Both perforators produced two types of perforations, some were perforated through the margin : perf P and others had no margin perforation : I perf. I might mention at this stage that they also also have either a rough cut or smooth cut guillotined edge to the margin. 

I was informed that they were perforated in lots of 60 panes, of these 60 panes 48 panes were perforated through the margin which leaves only 12 I perf imperforate marginal panes.

Of these 12, only 1 pane was incorporated with the imperforate (½V) cut edge. which goes to explain the high catalogue pricing for the I(½V) pane. Only one from 60. So there we have it.

The left selvedge of the sheet is imperforate, and after the perforating operation this is trimmed to the binding width,  with either a rough cut or smooth edge as mentioned above. The right selvedge was torn off, as was the bottom gutter. The slanting cut was made at the bottom in the left selvedge, to make the operation easier for assemblers to tear across the perf line.