In March 1900 the British Army captured the Boer capital of Bloemfontein. Stocks of existing stamps were seized and overprinted with the letters V.R.I. (Victoria Regina Imperatrix) and the value. Once overprinted stamps were valid for use with the British run postal service.
The printer appointed to the task was Curling and Co., who were a small Bloemfontein printer with no previous experience of security printing. Under the control of the British Army Intelligence Office, postage, revenue, and telegraph stamps were overprinted a pane (of 60 stamps) at a time using a hand press with manually set type.
There appears to have been little forward planning by the Army and as a result the printer was forced to switch continually between different types and values of stamp. For example, there are five or six settings [different overprintings] of postage stamps, two or three settings for revenue stamps, and two for telegraph stamps. The printer was forced to reset the type in the printing frame each time the setting was changed. This must have caused considerable annoyance since the work involved in setting up the frame was not trivial. However, a practical result of this was that part or all of the frame was changed regularly; worn letters were replaced (often from a different fount) and there are minor differences in the way that the frame was reassembled. These differences allow us to deduce the order of printing of the various types and values of stamp.
In addition, there is considerable evidence that unauthorised overprinting occurred. This appears to be due to the printer extending 'favours' to friends and local companies rather than a malicious act. Blocks of stamps rather than panes were overprinted and there is at least one documented case of already obsolete OFS stamps being overprinted.
All in all, this confusion has created a rich variety of overprints, with interesting errors such as changes of fount, missing stops, and double or triple overprints. In addition, there are a few more spectacular errors, such as missing values or incorrect overprints.
Obviously, there was a period of transition whilst the original stamps were being overprinted, and although this was fairly short, there are examples of old stamps being used under the new postal administration.
In some cases it is possible to determine the setting of an individual stamp, but most often determination requires a block of stamps so that a number of different flaws or errors can be located accurately.
The first postage setting is characterised by all level stops and a thin V.
The second postage setting has a thin V throughout and mostly raised stops; however, some positions have one or more level stops, leading to mixed raised and level stops.
An interpanneau block of 8 of the 1d on 1d purple from the right hand sheet, with margins. The block contains the last four stamps from the bottom row of the top pane (positions 57-60) and the corresponding stamps from the top row of the lower pane (positions 3-6). Position 57 (top left) shows the variety damaged left serif to V and position 58 (top, 2nd from left) shows level stops after the R and I.
The third postage setting has all stops raised and a thin 'V' on most stamps. However, early states have thick 'V' in seven positions.
A 1d on 1d purple showing an ink-blob above and to the right of the value. This type of error is transient and usually caused by a small fragment of paper or other foreign material sticking to the surface of the printing frame. The errors are not common because the foreign material either falls off or the misprinting is noticed and it is removed. This stamp has a thick V and raised stops and is therefore from either the third, fourth, or fifth setting.
2d on 2d purple with a level stop after the 'd' of 2d whilst all the V.R.I' stops are raised. This is a previously unknown variety since there is normally no stop after the value.