After doing more work, what I see on right is the fluorescent coated paper attribute. These papers sure make it complicated since they also react to UV light.
Preprinted phosphor paper stamps as defined in the catalogues tend to have a "mottled" effect across all the stamp, which I think is due to problems with the phosphor coating absorbing the printing ink of the design.
"Phosphor coated " and "Advanced (phosphor) coated" do not seem to have this problem.
However I am not certain that all copies of the stamps can be identified this way. I have only looked at postally used stamps, and the 10p PPP is in many cases easy to identify, if my conclusion is correct.
I have not seen any reference in print or on the www to actually give a step by step way to postively ID them, and in fact I may have drawn a completely wrong conclusion. perhaps one of the real experts here could comment?
Malcoolm
Through the process of elimination, I have confirmed an allover tagging example on left. The image on right is one of several prephosphorized paper (pp) types. Some pp types have low reaction and other have higher reaction under SW UV.
However, an allover looks like other prephosphorized paper so trying to determine what features help determine it is an allover type.
re: Identifying Machin "allover" tagging
After doing more work, what I see on right is the fluorescent coated paper attribute. These papers sure make it complicated since they also react to UV light.
re: Identifying Machin "allover" tagging
Preprinted phosphor paper stamps as defined in the catalogues tend to have a "mottled" effect across all the stamp, which I think is due to problems with the phosphor coating absorbing the printing ink of the design.
"Phosphor coated " and "Advanced (phosphor) coated" do not seem to have this problem.
However I am not certain that all copies of the stamps can be identified this way. I have only looked at postally used stamps, and the 10p PPP is in many cases easy to identify, if my conclusion is correct.
I have not seen any reference in print or on the www to actually give a step by step way to postively ID them, and in fact I may have drawn a completely wrong conclusion. perhaps one of the real experts here could comment?
Malcoolm