Gordon Piper.

This article from the Philatelic Database archives was first published in the Philatelic Journal of Great Britain April 1936 and read before the City of London Philatelic Society on 2nd March, 1936. It was awarded the “E H. Brandt” Prize:

A very interesting paper on Double Prints and Blurred Impressions was printed in the December number of the “Philatelic Journal of Great Britain” by Mr. Gustav Olofsson, of Sweden. In this paper Mr. Olofsson referred exclusively to Surface Prints although I do not think he stated this. investigations have been confined to Recess Prints. Mr. Olofsson stressed one point, with which I entirely agree, when he said that: “a stamp is not to be regarded as a double print unless it has been printed twice over.” All other double impressions, or appearances of double impressions, are merely slurs or smudges.

I have been carefully through Gibbons’ catalogue and, of the fifty or sixty thousand stamps listed, there are only thirty-eight double prints of recess printed stamps recorded, of nineteen are British Empire and nineteen Foreign. The majority were printed before 1870 and the latest date is 1900. A genuine double print is therefore one of the rarest phenomena in philately. I mention the dates of the double printings because the method of printing these stamps, which I am about to describe, and the presses in use, was the method employed at the time. I am quite aware that more elaborate presses are in use to-day, and that the method has changed somewhat; possibly that is why there are no modern double prints.

In order to make my theory quite clear I will venture to remind you of the procedure in recess printing at the time in question. In the first place the printing is from a plate on which the design is engraved in recess, and not in relief as in surface printing. The plate, either of copper or steel, is first heated on a warmer very similar to the domestic plate warmer, or hot plate, the object of this being to keep the ink fluid. The ink is then applied with a pad of flannelette called a dabber. When the plate has been inked all over, and while it is still on the warmer, the ink is carefully wiped off the surface with a pad of muslin in such a manner as to leave ink in the recesses of the engraved design. The plate, still warm, is then put into the press and a sheet of damp paper laid on it.

Figure 1. Diagram of Printing Press.
A. Upper Roller. B. Thick Blanket covering Roller. There should also be a loose blanket overlay over paper. C. Paper D. Plate. E. Sheet Bed. F. and G. Rollers on which Bed moves. H. Lower Roller. The lower roller is coupled to the upper by a screw which gives great pressure.

The press for recess printing is by no means the same as that used for surface printing. A very much greater pressure is required to force and mould the paper, even though it is moist, into the often minute lines of the engraved design. Such a press is very similar to the old-fashioned mangle, and I have here a diagram to illustrate the principle, but it is not a drawing of a press, many of the details being omitted. The plate with the damp paper and a layer of thick blanket on top of the paper is placed on the steel bed and the wheel of the press then turned. This causes the bed with the plate and paper to move forward between the tremendous pressure of the rollers. It goes right through and out the other side; the blanket is thrown back and the paper peeled off the plate, and the print or pull is done. In taking this pull, most of the ink has been drawn out of the engraved lines of the plate, and to make another printing it is necessary to do the heating and inking all over again. From this brief summary you will see that the making of a single print from an engraved plate is very much of a ceremony.

Figure 2. Examples of Recess-printed “Double Prints.”

The fact that it is such a ceremony makes it all the more surprising that a sheet could possibly be printed twice over. In order to try to solve this problem I had a plate engraved with a design of my own somewhat resembling stamp, and persuaded a firm who had printed several issues of stamps for the Colonies and
elsewhere, to try some experiments. The results of my experiments, which I place before you, are as follows:

Figure 3. Illustrations of prints from Mr. Piper’s engraved Plate showing normal and “double” impressions as described in his paper.

The normal method of printing is to put the plate once only through the press, as already explained; this entails the operative moving round to the other end of the press to remove the pull and plate. Perkins, Bacon invented a press, called a D press, in which the upper roller was cut in half, When this half roller had made its turn there was a space left and the pressure taken off, and the plate and bed could thcn be drawn hack to where they were without the operative moving. This was very satisfactory, but D presses were not universally used at that time. The result was that some operatives put the plate through the press once and then reversed and brought it back to where it started, thus passing the plate through the press twice. This is a method frequently used by printers to-day. The point is, that if by any chance the paper is touched or moved before it starts on its return journey, there will be a double impression. This, I am convinced, is the cause of all true double prints.

I show a number of double pulls which have been treated in this way, and I think you will agree that they closely resemble the true double print stamp. It is to be noted that the perfectly clear normal impression shown with them has also been through the press twice; in the case of the double impressions, the paper and the blanket overlay were knocked or shaken before they went through the second time, which could easily happen by the operative colliding accidentally with the press. As regards the slurs, or smudges, which are often dignified with the name “double print,” my investigations have shown that they are produced, or possible of production, by two means: In the first place excessive moisture; the paper may be too wet, or the blanket may have got wet in the course of the day’s printing, having absorbed moisture from the successive papers put through. Such excessive moisture, under the pressure applied, causes the ink to run. or “shoot,” as it is called. I show an example of this in a sheet which the printer has thrown out for this reason. You will note that he has put a pencil cross through the defective portion. This is printer’s wasie, and should be destroyed by the printer, and I might here mention that all double prints, and other philatelic errors, are really printer’s waste, and should never have got into circulation.

The second cause of slurs is faulty wiping. There is a practice much employed by printers of etchings called retroussage or dragging-up; it is possible by using a clean pad of muslin to drag a portion of the ink out of the engraved lines on the plate, when wiping, and so to make a species of double impression. This can also happen inadvertently in hasty wiping. I show an example of this from my plate.

I trust that this brief explanation of my theory may help to clarify the problem of double prints, and, if it saved some philatelists from buying smudges or slurs of no value, and wringly designated double prints, it will have served a purpose.