Does Long Wave Lamps Show Paper Varieties?

I am enjoying testing my new short and long wave light. Using the long wave lamp shows 3 different colors on the same issue of Scott #2133a. All five stamps in both images do not reveal any of the color variations under shortwave.



These Scott #2453 may help to explain the above stamps. I am just guessing but the purple color under long wave looks like it might be some kind of coating applied to the stamps with the left stamp showing an incomplete coating.

The purple color is the basic color of the paper if there is no taggant present. Neither stamp you show is supposed to be tagged since they are pecanceled. Long wave UV will show ( among others ) if any brighteners have been added to the paper. Can you tell us the model of the UV lamp you have?
Also, are you stamps mint or used? The 05 cent Canoe on the left side looks like it has a problem, like maybe an environmental issue.

Peter

Peter, all 5 are used, none are tagged. A number of other transportation issues I have show similar problems as the left Canoe. I have a Lighthouse L81. No doubt it is not the best but the really good ones were much more than I am willing to pay.

If the various colors under long wave are indeed due to brighteners, do the colors identify the brighteners?

Quignt, first this. At least on US stamps it is more or less futile to check for tagging on a used stamp. The canoe stamp with the strange looks is probably looking that way because of "migrant" tagging - taggant that came off another stamp. Could also be water damage due to soaking.
And yes, I think the different colors on the 12.5 cent are due mainly to brighteners but also to different papers used. According to the
1995 PNC catalog edited by Richard Nazar there were four different papers used on this stamp


Peter

Thanks Peter, I was suspecting different paper types so maybe these are explained of the four types mentioned by Nazar.

I've got a bunch of 05 Canoes I'll check in the next week or so to see what they show.

btw, I'm just curious about these and not looking for errors or rarities.

Peter, another question raised by your comment on migrant tagging. What I have found on all the transportation and other issues I have checked, the tagging shows as green. So wouldn't the migrant tagging also be green rather than purple?

Tagging is green - the canoe you show is greenish, at least the left side. Remember, checking the tagging should ideally be done on mint stamps, not on used stamps that have been soaked off.


Peter

More info on the tagging on the #2133 including images
http://stampsmarter.com/features/TaggingView.html
Don

Peter, both Canoe stamps are not green; they are purple as seen under my way long wave, in the original photo I took and in the image uploaded. I suppose what you see is possibly your computer interpreting it as green so I'm not doubting you see green. But I assure you the color is purple (slightly reddish purple rather than blueish). The purple color is on the right half and lower left corner, the rest of the left half is mostly blueish white with a bit of light purple shading. I say not green because looking at the stamps under LW with naked eye, they display a purple as displayed on my computer.

Quigngt, it is not important what that color is - it is a used stamp and is probably damaged by soaking.
Also, in your original post please add an "a" to the 2133. The three 12.5 cent stamps are Scott 2133a, not 2133.


Peter

Thanks for the link, Don. On it the colors on the 2133a are very similar to my post. On my computer and my post, the top two are same intensity in color but mine display with a bit of reddish tint (hence purple as I was telling Peter). The bottom third stamp (light gray paper) and my left stamp are almost identical. Differences are easily attributable to differences in how each computer "sees" the colors. Interestingly, my center 2133a stamp and the right 05 Canoe are identical in paper color. The photos I took of the Pushcart and Canoe were shot under the same conditions, settings, place and time with the same UV lamp. For what its worth, my computer is MacBook and camera is iPhone.

You are correct, Peter, the color we see on our computers is not all that important. Correction to 2133a will is fixed.

Under short UV, most U.S. stamps will glow a yellow green. Any purple that you see is the untagged portion of the stamp. If you check a block tagged stamp, you would ideally see a yellow-green rectangle in the center of the stamp while the borders, which are not tagged, appear purple. Note that a completely untagged stamp would not appear purple. It is the presence of the taggant on part of the stamp that creates the apparent purple.

"both Canoe stamps are not green; they are purple as seen under my way long wave"

The green glow from tagging only shows under shortwave UV not longwave UV

The odd look pf your left Canoe is just a chemically messed up stamp, not a paper variety

LW UV is one of the key tools to differentiate paper types. LW is used to determine/distinguish the fluorescence of paper. Levels I have seen defined for grades of fluorescence of stamps are: Dead, Non-fluorescent (NF), Dull Fluorescent (DF), Low Fluorescent (LF), Medium Fluorescent (MF), High Fluorescent (HF) & Hi-brite. You can google paper fluorescence to find more info.

As far as the odd coloring on the left Canoe, a common cause of this liquid dish soap. These have chemical brighteners in them to make your dishes look brighter/cleaner. It doesn't take much just a small drop. If you buy those mixed packages of 300-500 some dealers sell, many of the stamps will show degrees of this. Adding a few drops of soap breaks the surface tension allowing the stamp to soak off quicker. In the modeling world they call this wet water.