Question about Scott 401p-405p set

Greetings Mr. clintd
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Are you sure it is 401-405? That's the Panama-Pacific Exposition issue of 1914-15 perforated 10 and the 1-cent green Washington with the 190 watermark and perforated 12 of 1912. Tagging was not introduced to U.S. stamps until 1963.
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Respectfully,

Gordon Lee

Greetings Mr. clintd
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Righto. My bad. I access through the "Recent Topics" and I reckon I don't pay attention to the threads very good.
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Make sure you are using an ultra-violet lamp made to detect flourescent tagging. U.S. stamps use phosphor tagging and a different ultra-violet lamp detects those. They are two completely different lamps and will not detect the other tagging.
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A lot of those "cameo" stamps have a problem with migration of the tagging (it tends to wash, or fade). Plus, the cameos used various levels of fluorescent paper. However, those that I've check usually have a very defined "bright" spot or two when viewed with a fluorescent ultra-violet lamp.
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Respectfully,

Gordon Lee

Thanks Mike -- Informative site!!!