Questions:
1. Can I see the difference between stamps printed on prephosphored paper and phosphored paper?
2. How is the manufactured process for stamps printed on prephosphored paper and phosphored paper?
3. Will be the phosphor affected if a used stamp is soaked?
4. For simplicity a phosphored stamp is like a tagged stamp, isn't? Of course the chemicals used are different. Correct?
Thanks.
The phosphorescent agent (taggant) can be applied to the paper before printing, applied as part of another coating (mixture) prior to printing, or after it is printed.
The tagging applied before printed usually has what they called the mottled or grainy look due to uneven paper surface while tagging applied as a coating (mixed with other stuff in paper making process) has a solid (smooth, even) look. The tagging applied over the printing will can look smooth or uneven. It often depends on the mats used to apply it.
Sometimes you can see the taggant on the stamp if over printing especially on engraved stamps.
Yes, a stamp with phosphor applied one way or another is called a tagged stamp.
Now, after tagging/phosphorous stamps discussion is more or less clear and stamps has been used how can I separate them? Look at 4207-10 and 4207a-10a. How cam I determine which is a no "a" stamp and which is an "a" stamp? UV light will show a luminous stamp, but what type? Is there a simpler way to do it "precisely"?
The sheet version (4207-10) was overall tagged and the booklet (4207a-10a) had mottled tagging. The booklet version has one straight edge on each stamp. Since the booklet is easy to determine, this can be an example of showing tagging differences between mottled and overall.
I use a DSLR camera with a macro lens on a copy stand with 2 UV lights to get these images. You have to essentially force the camera to underexposure (at least 2 f-stops) to get the correct result. I do not use the wood supports but hold by hand.
You can "see" the same results with just one UV light but getting a good image is something else. For best viewing, you need to have a good UV light and view it in darkened room.
Cannot keep my promise! My questions just popup without knowing when they will stop!
It seems that your UV lights are better that anything I found right now in internet. Who is the manufacturer and where can I buy them?
Thanks, again.
Lighthouse, Raytech, and SAFE sells decent UV lamps. Most hobby supply places sell one or the other. You need to realize there are two types: shortwave and longwave. Tagging is checked with a shortwave.
Most lamps you see sold are 4W bulbs. These are not especially powerful and output does vary depending on battery condition (meaning brightest with new batteries). For shortwave use you often need to use in a darkened area since standard light can "wash out" the tagging (harder to tell the differences).
The lamps in my images are old Raytech units (metal case with AC plug). I got them off ebay.
One of the best ones around is the Raytech Versalume but it is expensive. It can be used in bright environments. I have one of those too. It works off AC or battery.
Astrophilatelist- Space Cover Collector 17 Dec 2017 03:39:06pm
re: About prephosphored paper
If you can find a copy of a booklet Linns Stamp News published in 1990 titled: Stamps That Glow it gives you very understandable information about tagging and paper types.
icard camera : https://www.ebay.ca/sch/Publications-Supplies/83274/m.html?item=182117701169&hash=item2a670f9631%3Ag%3AvfEAAMXQLoZR01~5%5B%2Fimg%5D&_ssn=cbenbow
