The stamps were printed in sheets of 240; they were divided into four panes that each had 10 rows of six stamps. They used two printing plates: one for the head of King George V, known as the head plate or vignette, and the second for the frame, known as the duty plate. A common head plate was used for all values and there was one duty plate for each value except the 25 cent value, which had one duty plate until 1919 when it was discovered that there was an incorrect Chinese character on it and a new plate was made
In some cases, requisitions for stamps to be overprinted were combined with the printings of the regular Hong Kong issues, but this was not always the case and they were sometimes printed separately. As a result, some varieties and errors are unique to the ‘China’ overprinted stamps and some exist on both the overprinted and un-overprinted stamps.
Once the sheets of stamps had been printed by De La Rue, they were set aside by the Crown Agents' Stamp Examiners and forwarded to Somerset House where the ‘China’ overprint, the Requisition Letter, and the Sheet Number were applied1. After the stamps were overprinted, they were returned to the GPO London who then forwarded them to the Postmaster General in Hong Kong to be distributed to the individual agencies
Perrin notes that some sheets of the regular Hong Kong issues were divided before dispatch. Each half sheet was composed of either the two upper panes or two lower panes. There is ample evidence that this practice extended to the ‘China’ overprints, at least in early printings. The 25c sheet of Requisition A (1917), for instance, comprises only the NW and NE panels with the bottom margin bisected. Inland revenue records show that the consignment delivered to Somerset house in 1916 for overprinting included both half sheets and quarter sheets
The rationale for these partial sheets is unclear. There is no evidence in the correspondence between the GPO and Hong Kong that they were asked for, and returns only dealt with full sheets of 240. However, the partial sheets must have been included, because the total forwarded to Hong Kong exceeded the number of full sheets printed in most cases. The breakdown to half and quarter sheets is found only in correspondence between the GPO and Somerset House.
It is also unclear why the lesser used dollar stamps were printed in full sheets while some of the others were split into halves and quarters. Additionally, the 8c and 25c were not bisected in the 1916 printing, even though the 25c was split in the 1917 printing. And although there were nearly equality quantities of the 2c and 4c stamps, nearly twice the number of half and quarter sheets were produced for the 4c2.