In addition to making the process of determining measurements simple and accurate, PSE3 enables one to examine the individual letters for fly speck defects and to compare the overprint with genuine overprints. I have a a reference library of 600 dpi images of blocks of 5 from full sheets, and extracted overprint images from several sheets of Forms 1, 2, and 4.
A scan of a 10h newspaper stamp is illustrated in Fig. 8. The extracted and enlarged overprint indicates a break in the bottom of the letter O of POLSKA. The top portion of the stamp indicates that this stamp came from the top row, positions 1 to 10. None of these positions on a genuine sheet show a broken O. However, I have photographed all positions of the top half of a 10h Form 6 (Forgery) sheet and position 2 does show the broken O. The lower image of POLSKA is that from position 2 of the 10h half sheet.
The measurements of the component parts of Form 1, positions 79 and 89 are the same. Comparisons of the extracted and enlarged overprints of these positions illustrate the differences which can identify these positions. See Fig. 9.
This is now the procedure that I use for the examination of these overprints.