Luminescents On Stamps
 
By Victor Bove
 
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U.S. stamps have various styles of luminescents, and Scott minor varieties are
often distinguished by the specific luminescent methods used. This information,
extracted from a BIA May 2000 article, identifies the different luminescent
methods used on U.S. stamps, and ways in which those methods can be identified.
 
Overall Tagging (OV) is a general name that includes any stamps that are
completely tagged by coating the stamps surface with tag after the stamp has
been printed. This includes the earlier types I, II, IIa, and III, as well as
later stamps that are completely tagged after printing by any of the current
presses.
 
Overall Tagging is produced by applying the tag over a stamp's printed image. The
selvedge of OV tagged stamps may be either tagged or untagged, depending upon
the width of the tagging roller or blanket. This more descriptive term was
needed to differentiate prephosphored papers (uncoated paper (UP) and Coated
Paper (CP)), from overall tagging types.

Overall, Uncoated Paper, and Coated Paper tagged stamps appear at first glance to
look the same under ultraviolet (UV) light, but they can be distinguished from one an other.
Separating UP from CP stamps is discussed along with their definitions under
Prephosphorous Paper (PP) tagging.
 
You need a few items to differentiate between OV and PP tagged stamps. The most
important item is a good ultraviolet lamp with ample power. RayTech products are
excellent. A lamp with sufficient power will cost a minimum of about $135.00 (as
of January, 2000). You'l l also need a soft vinyl eraser, an 8- to 10-power
magnifying glass and a large low-powered magnifying glass.
 
I use two lamps - a RayTech LS 7 and a Versalume by RayTech (or Scott Micro
battery powered portable when I am on the road). Any other cheap portable lamps
have proven to be a disappointment to me. Cheap lamps fail to filter out much of
the spurious white light that the UV bulb produce along with the short wave UV
light. This white light can mask weak tagging and also makes it impossible to
separate OV from PP tagging, particularly if the paper fluoresces brightly.
 
An example of OV tagging is Scott #1854 11 Partridge. Examples of uncoated
paper (UP) tagging are Scott #2184 29 Warren and #2186 35 Chavez. Examples of
coated paper (CP) tagging are Scott #2933 32 Hershey and Scott #2185 29
Jefferson.
 
OV and CP stamps can most easily be distinguished by rubbing the stamps' tagged
surfaces a few times with your fingers, using medium pressure. OV tagged stamps
always leave a heavy residue of tagging on your fingers, which is easy to see
under UV light. CP stamps transfer very little or no luminescent material to
your fingers. This is a definitive method for separating CP, and OV stamps
without damaging them. UP tagging transfers some material, but a much smaller
amount than OV. The rougher surface of the UP (compared to CP) causes the extra
tag transfer. The mottled tagging of UP is very distinctive. UP stamps can be
distinguished from OV mottled tagging and CP by this feature alone.
 
It is very helpful to identify and set aside reference copies of these three
tagging methods, for studying their characteristics and identifying other
issues. I recommend using Scott #2933 for CP, #2940 for grainy CP, #2186 for UP,
and #1854 for OV.
 
Dull tagged OV and CP copies on fluorescent bright paper are the most difficult
to differentiate. Remember the tagged stamps with any selvage that is not tagged
cannot be CP tagging. CP stamps will always have completely tagged selvages.