The new UV lights arrived earlier this week, I ordered both through Amazon, one a fluorescent UV light from Banknote World the other a LED UV flashlight. Both seem to be of good quality and I would have no problem recommending either one of them, depending on what you are using them for. Buuuut, we're talking banknotes here and one is better than the other, which will bring the question of "whether or not the label for anP82b in PMG holder is accurate" to a close. For reference, I initially examined the note using a single LED UV light mounted to a loupe.
The first test was with the LED UV flashlight, it has a 2 inch array consisting of 51 LED's and emits light with a wavelength of 395 nanometers. Light at a wavelength of 400nm or less is considered invisible (or UV) and is below the visible spectrum. Violet being the color with the shortest wavelength, between 380 - 450nm, is the last color in the visible spectrum, hence UV or beyond violet. It's also of note that just because a light is rated at 395nm not all the light emitted is at that wavelength, there will be a range +-, meaning that some of the energy or light will be in the visible spectrum at this ratting (395nm). So, I took my five raw "control" notes and examined them in a dark room with the LED UV flashlight. The fluorescence of the latent imprint was clearly visible, especially when compared to the single UV LED in my loupe. The security fibers were much more identifiable along with the background fluorescence in the center of the note. The paper also has a slight red tint using this light. So far so good.
With LED UV flashlight With single LED UV light in loupe Red tint to paper under UV and fluorescent background, gold in color.
Next is the Banknote World UV light and stand with a 4W 6 inch fluorescent bulb. There was no information on the tube but all similar fluorescent UV light tubes I researched had a wavelength of 365nm, which makes sense, as there is a difference between the 395 LED and this light. I examined the "control" notes under the fluorescent light and the results were even better. The latent imprint was even more visible along with security fibers and fluorescent background. The red tint appearance of the paper is much less/gone.
With Loupe With LED UV Flashlight With Fluorescent UV Light, background vivid, latent imprint clear and crisp, all security fibers clearly visible.
So it seems that a UV light that emits strongest at 365nm is the way to go. The wavelength range for the 365nm tube remains below the visible spectrum so as to not "washout" the note in visible light diminishing the effectiveness of the UV light/fluorescence of the features on the note. Also the LED lights seem to "spotlight" more, whereas the fluorescent tube emitted a more diffused light, more evenly lighting the note. Now, my conclusion has to be that my original method *vigorously inhaled" and I'd better check that P82b again with the better equipment. Here we go.
The label on the PMG graded note is correct!
Well, I was wrong about the P82b in the holder. Sorry everyone, false alarm.
The good news is that this was a lot of fun, I got to learn some new things, I upgraded my light situation, I can now put the note in my registry sets, I didn't send the note in for a label correction which would have been even more embarrassing and PMG was correct. The world makes sense again.