philatelia
Member 
Captain Jack - my best kiloware find ever!
Posts: 3,655
What I collect: Ireland, Japan, Scandy, USA, Venezuela, Vatican, Bermuda, Austria
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Post by philatelia on Feb 28, 2024 20:05:29 GMT
Just arrived and I’m impressed! These LED flashlights are so bright they work in a daylight room! They are rechargeable via USB and are handheld. Comes in a set of 2 - 395nm and 365 nm - for about $25 from Amazon. LOVE THESE! They even work on stamps in a Hagnar sheet! Fantabulous! I put my tongs in the pic for scale;
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renden
Member
Posts: 9,169 
What I collect: Canada-USA-France-Lithuania-Austria--Germany-Mauritius-French Colonies in Africa
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Post by renden on Feb 28, 2024 20:24:28 GMT
Just arrived and I’m impressed! These LED flashlights are so bright they work in a daylight room! They are rechargeable via USB and are handheld. Comes in a set of 2 - 395nm and 365 nm - for about $25 from Amazon. LOVE THESE! They even work on stamps in a Hagnar sheet! Fantabulous! I put my tongs in the pic for scale;
Terri, this UV would correspond to which Country ? Thanks René |
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philatelia
Member
Captain Jack - my best kiloware find ever!
Posts: 3,655
What I collect: Ireland, Japan, Scandy, USA, Venezuela, Vatican, Bermuda, Austria
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Post by philatelia on Feb 28, 2024 20:42:49 GMT
When you say “correspond” are you asking about international availability? I have no idea where they ship, René. You’ll have to check Amazon for that information.
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renden
Member
Posts: 9,169
What I collect: Canada-USA-France-Lithuania-Austria--Germany-Mauritius-French Colonies in Africa
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Post by renden on Feb 28, 2024 21:01:10 GMT
When you say “correspond” are you asking about international availability? I have no idea where they ship, René. You’ll have to check Amazon for that information. I meant there are 2 wave lengths to UV - Canada uses a longer wave length than USA - I have both right now. Your post looks interesting. René example This handy L81 UV lamp unites 2 functions in one device. Stamps, bank notes, credit cards, telephone cards, etc. can be examined for both fluorescence and phosphorescence. The combination of short and long UV rays (254/380 mm) makes the lamp especially practical for the user. Battery operated: 4x AA. 4 watt (254 nm) or 3-4 mW (380 nm). |
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clivel
Member
Posts: 387
What I collect: Basutoland, Bechuanaland, Rhodesias, South Africa, Swaziland, Israel to 1980, Ireland predecimal, Palestine Mandate
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Post by clivel on Feb 29, 2024 1:01:25 GMT
example This handy L81 UV lamp unites 2 functions in one device. Stamps, bank notes, credit cards, telephone cards, etc. can be examined for both fluorescence and phosphorescence. The combination of short and long UV rays (254/380 mm) makes the lamp especially practical for the user. Battery operated: 4x AA. 4 watt (254 nm) or 3-4 mW (380 nm). The flashlights shown by philatelia are both long wave, there should not be an appreciable difference in effect between the 395nm and 365 nm wavelength lamps or the 380nm of the L81 which is also long wave.
Some stamps require short wave UV in the region of 250nm. As far as I am aware shortwave UV LED are not generally available so it is unlikely to see these in an affordable pocket flashlight for some time. Clive
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khj
Member
Posts: 1,524
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Post by khj on Feb 29, 2024 1:13:29 GMT
US stamps need relatively short wavelength filtered UV -- ~254nm. But the 365nm is useful for detecting hi-bright paper, repairs, fungus/mildew... There are also a couple of pre-self-adhesive US stamps with taggant designed to respond to 365nm rather than 254nm. So if you collect US tagging varieties, having both is handy.
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renden
Member
Posts: 9,169
What I collect: Canada-USA-France-Lithuania-Austria--Germany-Mauritius-French Colonies in Africa
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Post by renden on Feb 29, 2024 1:27:55 GMT
example This handy L81 UV lamp unites 2 functions in one device. Stamps, bank notes, credit cards, telephone cards, etc. can be examined for both fluorescence and phosphorescence. The combination of short and long UV rays (254/380 mm) makes the lamp especially practical for the user. Battery operated: 4x AA. 4 watt (254 nm) or 3-4 mW (380 nm).
Some stamps require short wave UV in the region of 250nm. As far as I am aware shortwave UV LED are not generally available so it is unlikely to see these in an affordable pocket flashlight for some time. Clive
I have a shortwave UV, standalone and a long UV - René |
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khj
Member
Posts: 1,524
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Post by khj on Feb 29, 2024 1:57:11 GMT
clivel is referring to the short wavelength LEDs. Almost all the 254nm lights you see are bulbs, not LEDs. The 254nm LEDs are now available but pricey -- $20+ per watt for just the bare LED, and you would need at least 5-6 of them to come anywhere close to actually getting 4W. Eventually, a filtered 254nm LED light will be available at a good price, but I haven't seen it yet. Then again, the prices for the short wavelength UV lights (using traditional bulbs) have increased dramatically in the past 5 years. The dual wavelength unit I use, I just saw retailing at $400+ now!  Mine has lasted 35 years, and obviously didn't cost that much when I first got it. But you can get the near equivalent from the mineral/rock collecting vendors for almost 1/3 the price.
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angore
Member
Posts: 5,709
What I collect: WW, focus on British Empire
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Post by angore on Feb 29, 2024 11:10:02 GMT
This is an image of my 11 Watt shortwave (254 nm) lamp. It includes a longwave on the end. I just ordered a new lamp for it.  |
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philatelia
Member
Captain Jack - my best kiloware find ever!
Posts: 3,655
What I collect: Ireland, Japan, Scandy, USA, Venezuela, Vatican, Bermuda, Austria
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Post by philatelia on Feb 29, 2024 11:56:20 GMT
Absotootly right fellas! (spelling error intentional lol!) I should have specified that I am using these to check for certain fluorescent and bright white paper issues. I use my old trusty Ray-tech for 1960s tagged USA and other phosphorescent issues. I keep the two terms phosphorescence and flourescence straight in my mind with this mnemonic- phos sounds like fossil, so it’s the one used on older issues, but they may be old but their bones have stuck around - that helps me remember which one emits the glow longest. Silly, but it works for me!  |
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Mine has lasted 35 years, and obviously didn't cost that much when I first got it.