US Scott 3785A And 3785B - Can't Tell The Difference

I have two 5-stamp plate number coils which are supposed to be either Scott 3785A or 3785B. Both are dated 2003 in black, die-cut on all four sides, both are plate number P2222. According to PNC3.org (http://www.pnc3.us/pnc3.org/Data/Seacoast-ap.htm), 3785B is tagged and on prephosphored paper while 3785A isn't. When I run my UV light over them, they both show the same characteristics. The white edges of the stamps appear to have a purple tinge under the light and it looks "flaky". Also, on the stamp where you see the light orange clouds, the clouds "stand out"/"shine". Are these coil strips 3785B?

I don't know that I can help much, but I imagine it would be quite difficult for anyone can give you an on-line evaluation of such subtle differences in a stamp based on a description only.

What I can tell you is that the stamps you are questioning would be 3785a (lower case letter suffix) and 3785b (lower case letter suffix). It is important in stamp collecting to carefully identify the letters in the proper case, or you could be identifying a totally different item.

Further, the P2222 plate number was only available in 3785a or 3785b. I would err on the side of caution to suggest that your examples are 3785a, as that is the standard known variety that is most common at a catalog value of $1.50 for a PN strip of 5.

On the other hand, 3785b is considered a "tagging error" variety and the catalog value increases to $75 for a PN strip of 5. If it is indeed a "tagging error" variety that you have, you'll probably have to get it expertized in order to ever sell or trade it as the "tagging error" variety.

Mmm, thanks for the information. Do you know of any places that you could mail stamps in for examination?

If I understand your post correctly, both your stamps have the same appearance under UV light. Make sure you are using short wavelength (~254nm) UV light.

Based on your glow description, you have the untagged 3785a. My PNC collection stops before then, but I'm pretty certain that 3785b will glow a pale green under short wavelength UV. With only a handful of exceptions (almost all of them on commemoratives), tagged US stamps will either photoluminesce green or red.

Oops. No clue if my light is shortwave (It's a Guardlite handheld blacklight). None of my stamps glow like you described. Looks like it's time to find a new blacklight.

Edit: Filtered or unfiltered?

I use a large filtered dual wavelength UV lamp, but its expensive and is a little overkill for most philatelic purposes. I can light up a whole sheet of stamps. The lamp was not originally for stamps, but turned out pretty handy. I would not have bought that lamp had it only been used for stamps.

If your only purpose is to detect tagging on US stamps, all you really need is a simple short-wavelength UV lamp. These are usually available from most philatelic suppliers. I don't know the current cost, but I would think they are probably $20-$30. They are battery operated, and you may have to turn off the desk lamp in order to see the photoluminescence. The bigger, more powerful UV lamps will be more expensive.

Don't use those general consumer UV lamps ("black lights"). While they are bright, they are broad spectrum (both long and short wavelengths). The result is that your shoelaces and the entire stamp paper will glow and sometimes interfere/mask the taggant glow. I'm thinking that's probably what you are using.

I recall a couple of threads on buying UV lamps. So try doing some searching. I think the name of one of the suggested higher grade lamps was RayTech (or Ray Tech)?

Ok, I got another sample. I ran a blacklight over the three PNC5's and this is what I got:



Though it's hard to notice in the picture, the middle strip glows much brighter than the other two. Could the middle one be prephosphored (3785b)?

Blurr - you have to use a shortwave UV light to detect US tagging (your are looking for a yellow-green glow). Longwave UV won't detect US tagging (what LWUV can show is whether the paper is hubrite or dead - hibrite means the paper has had optical brightener chemicals added into the paper), and many cheap SWUV lights leak enough LWUV light (if they don't have a filter) and if the paper is hibrite it can swamp your ability to see tagging.

I am quoting myself from a post above.


You need to use a philatelic shortwave UV lamp, or a filtered shortwave UV lamp. The UV lamps you get from the department/novelty stores will not do the job in detecting luminescent tagging.



Maybe, and maybe not, for the reasons mentioned by eyeonwall. Need to use the proper UV lamp to tell.

a very handy little UV lamp is available from the people at www.uvtools.com. Model M-12 and comes with both long- and short wave lights.

I just bought the M-12 from there, thanks Petert. Hope it doesn't take too long getting here.

Darn. I got the shortwave UV light today, and none of the three samples glowed. What a disappointment. For a second I thought that it might have been my UV blocking contact lenses or something but then I saw an unrelated strip glow bright green.

Sorry to hear you don't have one of the luminescent varieties. Thanks for letting us know your results.

Blurr, please don't feel bad! But now you have the light you can scan every stamp on your incoming mail. Stamps that are supposed to be tagged are found untagged fairly often, and the same goes for untagged stamps that are found tagged.
Another thing, the same stamp can sometimes be found printed on high brite paper and on regular paper; happens with coils all; the time!