Discussion - Member to Member Sales - Research Center
Discussion - Member to Member Sales - Research Center
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It depends on the stamps you want to check and what you are looking for. Fluorescence is examined with a long wave uv light, whereas phosphorescence is best seen with a short wave uv light. And within these two main categories there are many differences, so there is no easy answer I am afraid.
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"Be prepared" is a good motto. What lamps, etc. do people usually have in their arsenal? I have an unfiltered UV flashlight, but I am not sure of the wavelength. I have ordered a blacklight in the 390 range. Is there another to have?
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Here's a link to some more information:
http://stampsjoann.net/ftp/tagging3.txt
Also, there have been several discussions about this in the Discussion Board in the past. Here is a link to the best one:
https://stamporama.com/discboard/disc_main.php
A search of the Discussion Board reveals the following. Scroll down a little to the "Supplies, Literature and Software". You'll find 6 threads relating to UV lights. Other threads in the search results may also prove interesting.
https://stamporama.com/discboard/disc_search.php
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I have two (LW and SW) from Lighthouse and a Versalume (both LW/SW) from Raytech. They are not the most powerful and need to be used in darkened areas for good results.
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To repeat ad infinitum ad nauseam -DO NOT look directly at the light from a short wave light.In fact it should be used in a completely dark room with your eyes firmly closed - you only open your eyes when you switch the light off ( you are only looking for the residual "afterglow" anyway).
There is a school of thought that while the uv emissions from a low voltage lamp used occasionally may not be dangerous it is generally accepted that repeated exposure to such emissions over a period of time is definitely harmful,so why take any risk ?
Bearing in mind the long term effects of "passive" smoking, and exposure to other harmful material, you ignore the warnings at your peril.
Sorry to repeat the obvious - but unless you shout in some people's ear from 6 inches they do not hear.
Malcolm
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Hi hayesherb;
malcolm197 is absolutely correct, these lights are very harmful, when not used in a well thought out and safe manner. Keep these away from small children as well. Children may think they are cute toys or Jedi light sabers.
To give some prospective to this danger, it is very much like staring at an arc welder in use. There is a reason why all welders are required to use those cumbersome helmets. OSHA (Occupational Safety and Health Administration) levies huge fines for use of an arc welder in a shop full of workers unless a opaque black curtain is placed between the worker and other bystanders.
Altho the dosage received from these lights is less than an arc welder, it is the same form of energy and similar wavelengths, just smaller doses. Over time smaller doses become large doses and your eyesight will begin to fail.
Some form of tagging can be detected without any special lights at all. This is common on many Canadian stamps. The early forms of taggant would turn dark and look like yellowish to light tan toning in the form of stripes. This is normal and not toning, just a taggant that has oxidized over time.
Many Canadian stamps can be held at an angle and a stripe of the stamp has a distinctly duller appearance than the rest of the stamp surface. It is very common and very easy to detect, if you know what to look for. Once you have identified stamps using UV lights, turn off the UV and observe these dull areas in normal visible light. Then you will be able to identify stamps that have this taggant applied without the use of UV.
Just sortin'....
TuskenRaider
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For those who collect GB Machin stamps the early stamps' taggant can be seen easily with the naked eye. However Royal Mail changed the formula on later issues specifically to "hide" the visual affect to improve the appearence of the stamp. For these you have to use a s/w uv lamp, but as I stated above you are looking for the afterglow so you don't need to actually see the stamp while the lamp is on - actually it is a mistake to do so, as the affect can disguise difference in the flourescent paper coating, which is best examined by a long wave lamp (which does not present the same dangers - although I wouldn't stare at one of those either).
There are other safety measures you can take too.Always use indirect light - in other words shield the light and look at the reflection on the stamp, and wear spectacles. If you don't have to wear them buy some plain glass ones or better still invest in some uv shielded ones.
As has been stated above it is the cumulative effect that is the problem and any way to reduce the total emission you are exposed to is beneficial.
Malcolm
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10:21:21am
Is there a recommendation on what type of UV light one needs to see most fluorescence/phosphorescence? Do people use these for watermarks, also?
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Approvals
re: UV light
It depends on the stamps you want to check and what you are looking for. Fluorescence is examined with a long wave uv light, whereas phosphorescence is best seen with a short wave uv light. And within these two main categories there are many differences, so there is no easy answer I am afraid.
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this post
11:02:40am
re: UV light
"Be prepared" is a good motto. What lamps, etc. do people usually have in their arsenal? I have an unfiltered UV flashlight, but I am not sure of the wavelength. I have ordered a blacklight in the 390 range. Is there another to have?
Login to Like
this post
11:10:06am
re: UV light
Here's a link to some more information:
http://stampsjoann.net/ftp/tagging3.txt
Also, there have been several discussions about this in the Discussion Board in the past. Here is a link to the best one:
https://stamporama.com/discboard/disc_main.php
A search of the Discussion Board reveals the following. Scroll down a little to the "Supplies, Literature and Software". You'll find 6 threads relating to UV lights. Other threads in the search results may also prove interesting.
https://stamporama.com/discboard/disc_search.php
Login to Like
this post
re: UV light
I have two (LW and SW) from Lighthouse and a Versalume (both LW/SW) from Raytech. They are not the most powerful and need to be used in darkened areas for good results.
Login to Like
this post
11:36:13am
re: UV light
To repeat ad infinitum ad nauseam -DO NOT look directly at the light from a short wave light.In fact it should be used in a completely dark room with your eyes firmly closed - you only open your eyes when you switch the light off ( you are only looking for the residual "afterglow" anyway).
There is a school of thought that while the uv emissions from a low voltage lamp used occasionally may not be dangerous it is generally accepted that repeated exposure to such emissions over a period of time is definitely harmful,so why take any risk ?
Bearing in mind the long term effects of "passive" smoking, and exposure to other harmful material, you ignore the warnings at your peril.
Sorry to repeat the obvious - but unless you shout in some people's ear from 6 inches they do not hear.
Malcolm
Login to Like
this post
re: UV light
Hi hayesherb;
malcolm197 is absolutely correct, these lights are very harmful, when not used in a well thought out and safe manner. Keep these away from small children as well. Children may think they are cute toys or Jedi light sabers.
To give some prospective to this danger, it is very much like staring at an arc welder in use. There is a reason why all welders are required to use those cumbersome helmets. OSHA (Occupational Safety and Health Administration) levies huge fines for use of an arc welder in a shop full of workers unless a opaque black curtain is placed between the worker and other bystanders.
Altho the dosage received from these lights is less than an arc welder, it is the same form of energy and similar wavelengths, just smaller doses. Over time smaller doses become large doses and your eyesight will begin to fail.
Some form of tagging can be detected without any special lights at all. This is common on many Canadian stamps. The early forms of taggant would turn dark and look like yellowish to light tan toning in the form of stripes. This is normal and not toning, just a taggant that has oxidized over time.
Many Canadian stamps can be held at an angle and a stripe of the stamp has a distinctly duller appearance than the rest of the stamp surface. It is very common and very easy to detect, if you know what to look for. Once you have identified stamps using UV lights, turn off the UV and observe these dull areas in normal visible light. Then you will be able to identify stamps that have this taggant applied without the use of UV.
Just sortin'....
TuskenRaider
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05:27:53pm
re: UV light
For those who collect GB Machin stamps the early stamps' taggant can be seen easily with the naked eye. However Royal Mail changed the formula on later issues specifically to "hide" the visual affect to improve the appearence of the stamp. For these you have to use a s/w uv lamp, but as I stated above you are looking for the afterglow so you don't need to actually see the stamp while the lamp is on - actually it is a mistake to do so, as the affect can disguise difference in the flourescent paper coating, which is best examined by a long wave lamp (which does not present the same dangers - although I wouldn't stare at one of those either).
There are other safety measures you can take too.Always use indirect light - in other words shield the light and look at the reflection on the stamp, and wear spectacles. If you don't have to wear them buy some plain glass ones or better still invest in some uv shielded ones.
As has been stated above it is the cumulative effect that is the problem and any way to reduce the total emission you are exposed to is beneficial.
Malcolm
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this post