Post by firstfrog2013 on Jan 13, 2015 17:17:51 GMT
I was advised decades ago that early tagging migrates and to exercise caution mounting on pages with non tagged issues.At this time I want to finally move them to quadrilles.should I still isolate them to their own kind?? has anyone tackled this ? What did you do to "seal" in the culprit ink?does this only apply to the pre-centennial issues or are later tagged issues still in danger of contaminating the others??I really don't like modern issues but I'm the caretaker of what I have.
I'm going to be lazy and just steal some info I posted on SCF a couple of years ago ... I'll add a photo of my own in a separate post later.
Winnipeg tagging doesn't migrate, nor does OP2. OP4 is the bad guy here, the others are OK. Winnipeg tagging is noted for fading somewhat during soaking. OP2 is completely stable in that regard, you can soak it overnight and nothing will happen to the tagging. I don't know what causes the taggant to look so different on some of the Landscape definitives - perhaps it's some sort of reaction over time to atmospheric conditions, perhaps the taggant looked different right off the bat due to fiddling with its chemical makeup. I've seen some tagged stamps that are only available with OP4 (such as the 1972 Health Day issue) that have tagging that looks exactly the same as the colour seen with OP2 tagging (with the exception of a bunch of migration of the tag on those OP4 stamps). I've seen other OP4 stamps that are very pale under UV light, as you describe.
Winnipeg (phosphorescent) tagging is not at all the same as the OP2 / OP4 (fluorescent) tagging. Winnipeg tagging was intended to work based on the residual afterglow once the UV light is turned off (or, more likely, once the stamp is moved out of the UV light - I'm sure the automated equipment would leave the light on and just pass the letter through the UV source). You can see phosphor tagging a bit while the lamp in on, but it's most noticeable in a darkened room immediately after you turn off the UV light. OP2 / OP4 is scanned while it is in the UV light source - there is virtually no afterglow once the UV light is turned off, at least none that can be useful for any type of automation.
Winnipeg tagging bars on the Landscape issue are much wider than the 3 to 4 mm used for OP2 / OP4. I suspect that excessively narrow bars are not practical for Winnipeg tagging, as they probably wouldn't generate enough phosphorescence to guarantee that the scanning would work properly.
The cross-hatching you see on the tagged areas might just be due to the printing process used to apply the taggant. For Machin collectors, the tagging can be identified by the screen mesh used when printing the phosphor bars - some Machin stamps come with the phosphor bars printed with a screen that was 150 dots per inch, some are 250 dots per inch.
Robin Harris (the Unitrade catalogue editor) has a good page on his Adminware site that shows some images of the tagging found on Landscape definitives.
Phosphorescent Winnipeg tagging is basically light blue in oolour when viewed under the UV lamp. OP4 is basically greenish yellow, fading all the way to a sort of straw colour when it's really faint. Of course, the more they're faded, the more the glow of the paper comes out rather than the glow of the tagging. But I don't have my eyes open with the UV lamp on when I'm looking for stamps with Winnipeg tagging. I close my eyes with the room dark and the UV lamp on, and I don't open my eyes until I turn the lamp off. There's no way to mix the OP2 / OP4 stamps up with Winnipeg tagged stamps then, since the fluorescent tag has no afterglow. If it's still glowing after you turn off the lamp, then it must be phosphorescent Winnipeg tagging.
Your original question about "phosphor" tagging might lead you in the wrong direction. Phosphor is the glow-in-the-dark Winnipeg tagging, started here in 1962 and still used in the UK today. That stuff glows under UV light a little bit, but it works best immediately after you turn the light off - it keeps glowing for a little while and that's how the detection equipment works (from what I understand, it flashes short bursts of UV light at the stamp and reads the returned glow when the light is off). Ottawa tagging is what has been in use since 1972 and it only glows when the UV light is on - that is fluorescence (glow-in-the-dark is phosphorescence). Your Wildings / Cameos / old Centennials with Winnipeg tagging won't be at any risk of migrating tagging, that type isn't the problem.
There are two main types of Ottawa tagging, OP-2 (what's in use today) and OP-4, which was the initial formulation that caused all the problems. OP-4 migrates through paper (glassine is a kind of paper, so it can't solve the migration problem). They figured out the problem relatively quickly, but even a small amount can turn into a large problem. I don't think OP-4 will migrate through plastic / Mylar, but it would probably contaminate the inside of a mount if you were to try to re-use it later. I suppose on a split-back mount it might even migrate through the gap into the album paper.
I've seen big differences under UV light of various OP-4 tagged stamps. I wonder if there are storage conditions that make the problem worse (for example, maybe damp & cold makes it worse, or maybe hot & dry makes it worse) - no idea, but there is a lot of variance. Some of the stamps I've seen have been horribly contaminated, big ugly fluorescent glow on the back of the stamp, whereas others hardly migrated at all. I've also seen different colours of fluorescence. Maybe there were various different OP-4 formulations as they tried to solve the problem.
OK, more snooping and I found another post I made back in the day, including a couple of photos I had taken under UV light. The shots of the back of the stamps clearly show the problem. Note that you would never be able to spot this problem without a UV light. So, if you don't care about UV lights, maybe you won't care about migrating taggant either!
Fluorescent tagging will glow only when the UV light is shining on it - as soon as the UV light is turned off, the tag stops glowing. Phosphorescent (Winnipeg) tagging has an afterglow that lasts a few seconds, and it's most easily seen in a completely darkened room. I have a guest bathroom that has no windows and that has become my UV room (I don't have any guests but I have a lot of tagged stamps!). Turn off the lights and shut the door and it's almost completely dark inside, and it's easy to spot phosphorescent tagging that way. I run the light over the stamps with my eyes closed, and then I turn off the lamp and open my eyes - the stamps with Winnipeg tagging jump out at me then.
Winnipeg tagging is somewhat susceptible to soaking - used stamps are often more difficult to identify than mint ones. I find this to especially be the case with British stamps, which use the same type of phosphorescent tagging method as the Winnipeg tagged stamps. OP2 tagging doesn't seem to care how long you soak it, it stays bright under UV light.
I'm sure there are storage considerations for all types of tagging, but I'm also sure there are unequal amounts of phosphorescent / fluorescent material in tagging. Some mint stamps can have extremely bright tagging whereas others are much less vivid.
OP4 tagging, the migrating stuff, is a bit odd in that it doesn't seem to be the same from one issue to another. Some of the high value Landscape definitives (like the 25c polar bears) from the early '70s have very faint OP4 tagging. Some stamps, like the 1972 8c World Health Day commemorative, can have very bright tagging. Colour can vary somewhat, and I don't yet have a good sense of what kind of tagging is what, because sometimes the OP4 can look almost exactly like the OP2.
The Health Day stamp is a good issue to look at (on mint stamps especially) when trying to understand the possible problems - you can often see tagging "soaking through" to the back of the stamp. Here's a photo of a horrible example, some OP4 stamps I got once in a glassine - everything glows to some degree, the front of the stamps, the back of the stamps (I've turned a couple over), the glassine envelope, probably the spot on the table where I've set the envelope ....
The stamps turned over are the Health Day stamps, and you can see the design of the 1972 Frontenac stamps (also with migrating OP4 tagging), which look pretty much the same on the back side. I've also attached a shot of a couple of different Health Day stamps turned over, which obviously show different levels of problems with tagging migration.
Last Edit: Jan 13, 2015 21:13:21 GMT by Ryan: how did those extra blank lines get in there?
Post by firstfrog2013 on Jan 13, 2015 20:31:53 GMT
Thanks Ryan that's a good bunch of info.I had thought it was the earlier stuff, sometimes mis information just sticks in my head I guess.Tagging has never been my thing,seems like everyone else gets excited about mistakes in the tagging process,not me.I have some issues set aside that should be examined under UV but it will most likely never happen.The same goes for all those paper varieties just doesn't thrill me.Now if we're talking large queens that I can handle or paper thickness in the admirals O.K. In my mind they're different some how.Thanks for your input.
I have tried unsuccessfully to take Photos of Fluorescing stamps before, I would be interested to learn how you managed to get such clear photos.
No great secret to that, I hold the UV light with one hand and the camera with the other. I have a UV light that's on the bigger side of things, one of the metal Raytech things with two different wavelengths. If I turn on both wavelengths and hold it close to the stamps, it makes quite a bit of light. The other part of the equation is to have a room that's as dark as possible. Not a problem for me at any time of day with my room with no windows, all I have to do is shut the door and stick a towel over the gap at the bottom, and I have a pitch black room. Lots of light from the UV lamp and no light otherwise and the pictures come out fine, even with a miserable little point & shoot digital camera. If I fussed with exposure and aperture and who knows what else, I could do much better, I'm sure.