Paper/Tagging On C76 Sheet

I was looking at the short-wave UV tagging on some c76 man on the moon sheets. Most of these are a pinkish-orange color, but I have one that is purplish. In the tagging database on stampsmarter.org (hope it's ok to reference it), they have paper types of DF & NF. I don't see any reference to these two abbreviations. Can anyone clarify it for me? Thank you. Attached is the sheet with others which have normal tagging.

Here is a better focused image.

Would it be possible to post an in-focus picture?


Peter

I did just before you posted. Refresh and you should see it.

You are not using a short wave (254nm) uv light, you are using a long wave (365nm) uv light in your pictures (or your short wave uv light does not block the long wave part adequately (which is often the case with those hand held 4AA battery thingies).

Paper may react to long wave uv light. In your case, the purple-ish color comes from non fluorescent (nf) paper (and from some residual blue light from the lamp and possibly from the camera sensor abilities). The white-ish glow means your paper shows a dull fluorescence reaction (df).
Grading paper fluorescence from dead to high bright is somewhat arbitrary. The reaction to long wave uv light depends on the amount of fluorescent matter in the paper (often fibers).
A good example is a hi-bright 1213a Washington booklet pane which really shines brightly.

Interesting. These were taken with a short wave light. I have a separate long wave UV light that I use.

My short wave light uses 3 D batteries. I don't understand why the source of power matters. It all ends up DC regardless of how it starts. It's a 13w 254nm light. I've been using it for several years. My long wave light is cheap, probably 365 to 395 nm range. I see no colors on the sheets with the long UV.

Thank you for the explanation on df vs nf. Much appreciated.

NF and DF are expressions for paper variance under lw uv, not tagging under sw uv. You don't see paper variance using short wave uv as the taggant strongly overlays any paper variance reaction.
My best guess is you have a picture of untagged and tagged sheets.

It is also not clear what camera you are using as there are camera chips that totally freak out when hit with stray uv light. Typically cell phone cameras do show weird colors not corresponding to what the eyes actually see. Again my hunch is that the sheet in your picture that doesn't glow shows a "false" blue-violet hue due to problems with the lamp and/or camera chip.

It's a 13w 254nm light
I often wonder about those Wattages people or advertisers quote. I built my own short wave uv lamp (with a thick glass filter in front to absorb the near-uv part of the emitted light) using an 8W lamp. 8W of short wave uv is very strong (these lamps are also used to sterilize rooms in hospitals, for example). When I switch on the sw lamp, I can immediately smell ozone so I can only use it with windows opened...
If your lamp really is 13W, you'd have to take serious precautions as breathing ozone isn't exactly healthy.

Listed at $20 now on ebay as, "Scott #c76 First Man on the Moon Airmail Sheet of 32 Stamps - MNH Tag Variant" using same illustrations as above and with seller's note, "Genuine, mnh, actual stamps in scan, tagging is purplish - shown with other c76 sheets which have pinkish tagging, Very Good Condition"

The density of the orange-red tagging on the early tagged US airmail stamps can vary quite a bit. I think this is the case with the middle one. The tagging is not as dense. I have seen this on quite a few different ones.

As far as the paper types, for example NF and DF. There are definitions on the stampsmarter site. If you go to the main Tagging Database page there is a series of tabs. One of them is paper types. This has the types defined for what you found in the actual database pages. They are based on a list in the Unitrade catalog of Canadian stamps and from discussions with Chris of BrixtonChrome.

Chris has a couple of great discussions on paper types in the Stamp School section on his website Brixtonchrome.com.