Why did the they put Lathework on hundreds of plates of the Admirals, Revenues, and Postage Dues? There is no certain answer to the question since no documentation has survived. Thus it is necessary to answer the question with a bit of deductive reasoning.

The first clue to the answer lies in a careful examination of the earliest examples of Lathework, types A and B. Close examination of large multiples of these types reveals that the original lower Plate numbers exist underneath the band of Lathework. This tells me that the lathework was applied to the plates after they had already been engraved. I cannot be certain that the original plates exist under every plate with type A or B but it is under all of the ones that I have, which amounts to thirty or so different plates. The fact that the ABN went to the trouble to apply a band of engraving on top the existing lower plate inscriptions would seem to imply that there was a good and compelling reason for this action. After all this was a business and I doubt that they invested the time of their staff for a trivial reason.

The second clue is the simple fact that after the use of Lathework ceased the engravers did not return to the practise of including lower imprints on the plates.

This indicates to me that the lower plates were being used for something more than just identification.

I thinks it is also important to note that the Lathework is often incompletely inked. I will not go into the old arguement about worn plates as I believe that it has been resolved.

It is also useful to note that many of the lower plate imprints found in the period before Lathework was introduced are also poorly inked and sometimes difficult to read.

It seems clear from the evidence that there was a problem with getting enough ink on the plates in the latter stages of the years in which the 'WET' process was used. I don't know much about the actual printing process but it seems logical to assume that the lower inscriptions were being used to tell the printers if they were applying a sufficient amount of ink on the press. The lower plate inscriptions were relatively faint at best and didn't show up well enough for the printers to quickly see if things were correct. However a thick band of engraving would show up plainly and the printers could tell at a glance if the amount of ink was correct.