Figure 1
A reduced image of the master sheet from which all of the photocopies were created. The machine code and density setting were written in on the first copy, whereas the generation number was applied only after the next generation was reproduced.
Table 1
Photocopiers Used
| Code | Photocopier Model | Technology | Paper Feed |
|---|---|---|---|
| N/A | Minolta® 2152EP* | Analog | Top First |
| 1 | Xerox® WorkCentre Pro 412 | Digital | Top First |
| 1027–1 | Minolta® CSPro EP5050 | Analog | Side First |
| 1027–2 | Panasonic® DP-150FX | Digital | Top First |
| 1027–3 | Panasonic® DP-3000 | Digital | Side First |
| 1027–4 | Panasonic® FP-7818 | Analog | Side First |
| 1027–5 | Panasonic® FP-7750 | Analog | Side First |
| 1027–6 | Sharp® AR-205 | Digital | Side First |
[i] *Only used in the trial run.
Figure 2
The master sheet bears four original signatures. Each signature was reproduced on seven different photocopiers. Each copy was successively copied to extend twenty generations from the original. This was repeated for three different density settings on each machine (light, medium and dark). In total, 84 permutations x 20 generations produces 1680 individual copies. This structure does not include the initial trial run, nor does it take into account instances in which the image either failed to reproduce (too light) before the twentieth copy, or the page became too dark to complete the series.
Figure 3
The Graphical User Interface (GUI) designed to allow easy selection of the various copying parameters and display of each copy generation series. Right-clicking in the image display area permits access to additional controls.
Figure 4
The column of images on the left shows the original signature followed by generations 5, 10, 15 and 20 from the Xerox® WCP412. The copies from this machine showed “blooming”—progressive thickening of all marks. Those from the Panasonic® DP-150FX showed “beading”—a breakup of lines to form a series of dots.
Figure 5
The upper images show a first generation photocopy of a blue ballpoint signature produced by the Xerox WorkCentre Pro 412. This digital machine produced images that very closely approximate the line morphology seen in the product of some gel pens (lower image). Consequently, qualification is called for when identifying a writing as having been produced by a gel pen based on the assessment of a photocopy.
Figure 6
The images above are taken from the first, tenth and twentieth generation photocopies using the Panasonic DP-3000. The non-linear distortions are extreme in every aspect and include vertical undulations as well as horizontal displacements. Note that the spacing between the left reference marks has increased, while those on the right have decreased.
Figure 7
In cut-and-paste or tracing cases the degree of non-linear distortion introduced into later-generation photocopies may render superimpositions of the original and model signatures less than convincing.