Darwin PSB Machins - now two types!!

Back in mid-January I reported (here-link) that the Machin definitives in the Darwin PSB were quite different to those printed in ordinary counter sheets, the 5p being especially dark. Discussing this with collecting friends we concluded that there was too much ink used - or that too little had been wiped from the cylinder during printing. This view was reinforced by the fact that some of the panes showed flecks of dark-brown ink on the reverse of the 5p stamps where panes had stuck together. This was not because of water-moisture, which would normally have caused the paper surface of the lower stamp pane to be damaged, but because the ink was not sufficiently dry, and thus only the surplus ink is slightly offset on the lower pane.

My data came from the unbound panes that we were sent for use on covers. However, in a second delivery of unbound panes the stamps are much more 'normal', as you can see in the picture - the newer pane is at the top, and you can clearly see the phosphor bands on the 5p, whereas the lower pane is darker and slightly blotchy. The 10p and 48p stamps are also different, but less obviously. Interestingly the dark green patterned background to the pane is lighter on the original than on the version received later, being almost totally lacking in definition on the upper image. All these were distributed by the Royal Mail's Philatelic Bureau.


The actual books that we received here (also from the Bureau) contained stamps of the second type, leading several collectors to assume that the early part of the printing - partly used for dealer distrubutions of unbound panes - was over-inked and that this was soon corrected (partly to replace dealers' damaged panes), the lighter printing being used for binding into the actual booklets.

However, a purchase from a local post office has revealed that the over-inked panes also exist in bound booklets. So were there two printings? Let us know which 'printing' is in the books you have!