Help Needed With "Tagging Omitted"

We came across few stamps with "Tagging omitted" in 2013 catalogue, and we are trying to understand it. We understand "tagged" using shortwave uv light for US stamps. We have Scott # 1356, block of 4, (mint) and we noticed the words "Tagging omitted" and trying to understand what are we looking for with this "tagging omitted". We are assuming if it isn't tagged then it would be worth $6 instead of $.25 each, correct? TIA.

The term tagging omitted does imply that the item (stamp/block) is untagged. It is used only in reference to stamps that were otherwise always tagged ... with the possible exception of bureau precancels (precancels are normally untagged). Hence "tagging omitted" would also imply that the stamp(s) are not bureau precancels. Tagging omitted items are also considered, somewhat ironically, as missing color errors. Since they are errors, they will always be more valuable than their tagged counterpart.
Quite a few stamps have been produced both with & without tagging. For a few of these, accidentally untagged stamps can be distinguished from deliberately untagged stamps. An example is Scott #2170 (3-cent Paul Dudley White). 2170 is the tagged version, 2170a is the deliberately untagged variety, and 2170b is the accidentally untagged (hence, tagging omitted) variety. Normally, the way in which 2170b is identified is by plate number, although it can also be identified by paper/gum type. Scott #2169 (2-cent Mary Lyon) is yet another example.

I didn't read this close enough last time...Why would the USPS "intentionally" not have tagged a stamp that is supposed to have been tagged? Just for collectors?


-IBFS

"Why would the USPS "intentionally" not have tagged a stamp that is supposed to have been tagged? Just for collectors? "

In the case of something like 1900 vs 1900a, they did exactly that. In the case of 2170a, the original 2170 was issued tagged, then they changed the tagging policy so that all values below a certain value (which I think may have been 10c) were to be left untagged (so the postal equipment would catch envelopes with say just a 5c stamp on it that they were trying to sneak through), so when the 2170 was reprinted after this change they were intentionally untagged.

Dumb question alert: This is a dumb question. Really dumb.

I know about the rule change of not tagging stamps below 10 cents in vale, but I don't understand how it would work since the machines only saw the stamp's tag, not the value.

If I needed to mail a letter, and it costed 40 cents to mail, I could have used a 20 cent stamp, and then 4 5 cent stamps. The machine would see only the 20 cent stamps, send it through, and I would have just mailed a letter for half price. Not a real practical example, but you get the idea. I'm missing something. But what?


-IBFS

You are correct. Automatic cancelling equipment cannot detect a stamp's denomination. This is why I once received an ebay purchase in an envelope with a single tagged 10-cent stamp. This is also why my aging father was successfully able to mail his Christmas cards for two consecutive years with 41-cent stamps when the postal rates were 42-cents & 44-cents. Since the postal service never complained, I saw no reason to tell him that he should be using additional postage. In effect, anyone can use an old tagged stamp of any denomination and it is likely that their mail will be delivered. Of course, sometimes a human will notice ... and then there will be postage due or the item may be returned. This happened to me a couple of years ago when, while at the post office, I carelessly placed lick-and-stick stamps on a glossy surface. By the time the parcel reached a PO near its destination, most of the postage had slid off, never again to be seen. The package was returned and I got to mail it a second time.

Thanks JL.


-IBFS