Fluorescent Vs Optic White Paper

Fluorescent vs Optic White Paper

I have seen stamps printed on 'fluorescent' paper.

I have seen stamps printed on 'optic white paper'.

Q/ Same? Or, different?

Q/ Where is Alfred 'Tag' Boerger, now that I need him?

Cheers,

/s/ ikeyPikey

I assume they are the same. Optical brighteners use fluorescence to give a vivid white appearance.

I too think they are the same. I can't imagine any color shift.

Can you provide an example of a stamp described using "optic white paper". I don't actively collect recent stamps and am not familiar with that term.

But in general, fluorescence is not necessarily white. A surface coating is often used to change they way/color/intensity of paper fluorescence. As KGB noted, optical brighteners can be used to make a paper fluoresce a vivid white. Likewise, coatings can be used to reduce/mask the fluorescence, or cover it up by fluorescing a different color (for example, tagging on most US stamps of the 1970s-1980s and many other later issues).

The description appears in the-online-stamp-catalog-that-dare-not-speak-its-name-on-SCF for certain stamps of Finland, 1963.

I remember Mr Boerger (z"l) referring to the early American fluorescents as "hi-brite" (presumably the extra-white way they looked under VIS light) while they fluoresced green (under UV light), and I can easily imagine the same additive doing both, but I thought I'd do well to ask here.

Cheers,

/s/ ikeyPikey

ikey, can you at least give a clue (rhymes with ____)? I have no idea what catalog might be unmentionable on SCF.

rusty, it may be c o l n e c t.

Thanks, KGB. I've never heard of it, so the no-mention thing is working.

IkeyPikey, you have to go a long way to get to talk to Al. I believe he passed away back in 2001 if I remember correctly.
I think 'Optic white' is the same as 'Hibrite' as I have seen the two used interchanged.
I believe 'fluorescence' is different. If I remember my high school days ( 100 years ago ) fluorescence is supposed to have an afterglow. They did tests with fluorescence in the 50's and that did not work out too well. One example of a recent fluorescent stamp stands out: Scott 2452Dg, the 5 cent Circus Wagon printed by Stamp Venturers and with plate number S2 and S3. These coils were printed with luminescent ink.
The tagging used on US stamps nowadays is phosphorescence which is visible under short wave UV light, while Hibrite paper is made visible under long wave UV light.
By the way, you use the abbreviation 'VIS'. I am not familiar with that one!

Peter

OK, thanks for that clarification regarding "optic white".

All luminescence has an intensity tail, the only question is how fast it tails off. Relatively speaking, phosphorescence has a longer "afterglow" than fluorescence. However, in different circles, you will often find the scientific definition not rigorously adhered to, especially among stamp collectors.

On the US stamps of that era, the green (or red, on some airmail stamps) is luminescence due to the chemical taggant applied to the surface of the stamp. The "hi-brite" varieties are luminescence from the paper itself, not the taggant. Therefore, on the hi-brite paper, you can observe the bright whitish glow on the back of the stamp as well. For taggant, it will only glow where applied (i.e., the front side of the stamp).

The photoluminescence will also depend on the excitation wavelength. For the US stamps, use filtered short-wavelength to observe tagging, and filtered long-wavelength to observe hi-brite paper. This, however, is not a general rule for stamps of all countries.

When the catalogs state "fluorescent paper", the are NOT referring to the surfacing tagging, but that the paper itself will actually photoluminesce.

I don't know Peter what American high schools taught but here in Canada it is the phosphorescent tagging that has the afterglow,
usually for a few seconds.

Phosphorescent tagging of Canadian stamps started in 1962 in Winnipeg but was replaced with fluorescent General(Ottawa) tagging in 1972.

Fluorescent tagging has no afterglow.
At least our Canadian ones don't.

That is the correct differentiation in science, lithograving. In the US, we tend to corrupt everything. Why? Because we can. PTTHHHH!!

No. The phosphorescent tagging only gives the yellow green. Any white (or often bluish white) fluorescent glow is either coming from the paper OR from some OTHER additive to the tagging layer. Optical brighteners were not supposed to be used on US stamps, but have been turning up on many US issues the last few years (and very strongly), and I'm not sure why.




No. Fluorescence is the same as hi-brite and optic white. Phosphorescence has the afterglow, not fluorescence (at least not in a long enough timeframe that our eyes can detect).




VIS = visible lighting