Could be an optical brightener - or the stamps have been soaked together with luminescent ones. Which color was the glow?
The stamps were a stark, even white on the gum and face side. No spottiness that it might have picked up from contact with a phosphor stamp.
Stark white sounds very much like optical brightener.
Fluorescence is mostly yellowish and remains visible while the (long wave) UV lamp is on, phosphorescence often reddish, sometimes purple-ish, but is visible as an afterglow once you remove the (short wave) UV lamp.
I was checking some Canadian stamps for tagging and a couple Netherlands stamps on the desk were glowing - obviously printed on phosphorescent paper (the other ones still looked dull).
1) I looked in my Scotts 2017 Catalogue and can't find a listing for a 6c phosphor version. Does anyone know of such a listing?
2) The 8c is listed as #406 in phosphor - but Unwatermarked. My copy has the circles watermark, but I can't find a listing for that version either. Anyone know what it would be?
Many thanks.
Dave
re: Netherlands Phosphorescent Stamps
Could be an optical brightener - or the stamps have been soaked together with luminescent ones. Which color was the glow?
re: Netherlands Phosphorescent Stamps
The stamps were a stark, even white on the gum and face side. No spottiness that it might have picked up from contact with a phosphor stamp.
re: Netherlands Phosphorescent Stamps
Stark white sounds very much like optical brightener.
Fluorescence is mostly yellowish and remains visible while the (long wave) UV lamp is on, phosphorescence often reddish, sometimes purple-ish, but is visible as an afterglow once you remove the (short wave) UV lamp.