Avbstamps

Victor Bove, serving collectors since 1960

Luminescents on Stamps

With pre-phosphorous (PP) tagging, the printing is on top of the pre-phosphorated paper. The tag glow under long wave (LW) UW light will therefore be obscured in heavily inked areas. OV tagging is applied on top of the printing, so it will usually be visible, although sometimes OV tagging will be masked by the darkness of the ink in heavily inked areas. Also, an OV stamp paper with enough fluorescent brightness can obscure the dull tagging on its surface.

Compare OV and CP stamps by holding the UV lamp so the light strikes both copies perpendicularly (straight on). The OV copy appears to be completely covered with a green haze, even in the heavily inked areas. Also, the edges of letters or numbers is slightly fuzzy. The fuzziness is caused by the tag binder softening the underlying ink while it's under the pressure of the tagging press. Heavily inked areas will tend to mask the intensity of the OV tagging. CP stamps appear much darker with no green tagging haze in the heavily inked areas, and the edges of letters or numbers appear sharp and crisp. A magnifying glass is necessary to see these differences. If this doesn't work, cut a small hole in a 2" square piece of thick paper. Make sure the paper is dead (has no fluorescent brighteners). The size of the hole should be small enough to view only one very heavily inked area on a stamp. I find comparing letters or numbers on the stamps has the best results. Now place the view hole over a letter, a number, or the most heavily inked area that you can find on the stamp. You want as little white paper as possible showing in the view hole.

When looking through the view hole under UV light, the OV stamp shows a green haze, whereas the CP stamps looks very dark, as most of the tag in the paper is covered by the ink. Again, note that the edges of OV tagged letters have a fuzzy look, whereas the edges of CP letters are sharp and clear. This is the most obvious difference to see, and it clearly marks the stamp as either OV or CP. A magnifying glass is necessary to see these subtle differences. UP tagging letters look the same as CP.

OV and CP stamps with dull tagging, and fluorescent bright papers are more difficult to identify. If the "rubbing", and "viewing" procedures fail, the following will work. You'll need two or more of the stamp that you're checking, as one will be damaged. Take a soft vinyl eraser and lightly rub a moderately inked spot on the PP and OV stamps about 10 times. Don't use a heavily inked spot as it will mask the results. Now check both copies under UV light. The tag on the OV stamp will be rubbed off without much change in the stamps, underlying ink. Confirm that there's no damage to the underlying ink with the 8 power glass. The PP stamp will show little or no difference in the tag's brilliance where you rubbed it (as long as you didn't erase the inked image). If the difference is not apparent after the first rubbing, repeat on each stamp until it is apparent. The only way for the tag to be dulled on the PP copy is if you rub through the ink and rub through the papers' surface on CP copies. The tagging glow of UP copies will not be affected by erasing the surface, as the tag soaks deeper into the paper. Practice on spare copies before you tackle your better stamps. Remember, any stamp that has attached selvage that is not completely tagged must be OV tagged.

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