Black Light Discussion:

[drcy]

The chemicals that fluoresce were added to paper in the WWII era, and to photopaper in 1955.

As mentioned, if a supposedly Pre-WWII item does not fluoresce, that does not prove it old, because some modern paper and cardstock do not have the chemicals. However, the lack of fluorescence is consistent with it being old-- a good sign and helpful evidence.

[JLange]

A black light, ruler, and magnifying glass are essential for vintage collectors IMO. There’s also nothing better than an example card that you know to be genuine for comparison. I know that’s not always possible with rare or high end stuff though. Many frauds and alterations are easily spotted using these items, but unfortunately not all.

[the 'stache]

Everything he said.

BTW, I have the same black light Steve does.

Originally Posted by JLange

A black light, ruler, and magnifying glass are essential for vintage collectors IMO. There’s also nothing better than an example card that you know to be genuine for comparison. I know that’s not always possible with rare or high end stuff though. Many frauds and alterations are easily spotted using these items, but unfortunately not all.

[drcy]

Timely enough, I am having published in the near future two books, one a new guide to authenticating early baseball cards and the second an introductory physics textbook on ultraviolet light. The first is obviously appropriate, but the second might be of interest due to all the fascinating areas ultraviolet light is used: authentication, astronomy, medicine, biology, geology, forensics, dentistry, security systems, etc.

So just wait a month or two and they should be out.

[dlfallen]

Here is an example of a black light in action. The fake is a 1957 Seattle Popcorn card of George Munger. Although printed during a time when some paper stock had whiteners that caused the paper to fluoresce, none of the Seattle Popcorn cards (1954 - 1968) fluoresce under a black light. It might be instructive to compile a list of vintage post-war issues that should not fluoresce.

I discovered this fake in my collection a couple of years after acquiring it. I believe the seller dealt in good faith and because so much time had elapsed I did not pursue the issue with him. This card does not come up often, but luckily I got one shortly after my "discovery" for about half of what I had paid for the fake.

[Leon]

Black lights are cheap and easy to use. I think all serious collectors should have one. That said the big takeaway from a discussion should be that a black light is only one form of detection AND not all counterfeits or fakes will fluoresce. Just because something doesn't floresce doesn't mean it isn't fake.

[samosa4u]

Thank you everyone for your responses. Today I went to Lowe's and purchased the Rayovac 9-LED UV Flashlight for $16 CDN. I waited for it to become dark outside, because that's the best time to use it, and I went over my collection. I made a few shocking discoveries unfortunately.

Anyhow, I see there is a sticker on the back of the package which says the following:

WARNING:
This product can expose you to chemicals including DEHP, which is known to the State of California to cause cancer and birth defects or other reproductive harm. For more information go to www.P65Warnings.ca.gov.

What exactly is DEHP? Is it really that bad? And why does it only mention California? lol

I ordered a cheap one from China as well for a little over $3 USD - these are the ones a majority of collectors probably use. I want to compare it to my Rayovac model once it arrives.

[drcy]

Don't stare directly at the light (as in shine it in your eyes), but blacklights are no more dangerous, and perhaps even less, than sunlight (which contains UV light). Sunlight, of course, can cause cancer if you're in it too long.

Blacklight is longwave UV-- that's what you have and is the most benign. Shortwave UV (which you don't have) is the more dangerous. However, even then, collectors are just using shortwave UV for a relatively short duration and shining it on objects not themselves, so it won't cause harm.

Shortwave UV lights are a lot more expensive that longwave, which is why I know what you have (at those prices) are the longwave.

An interesting factoid is that shortwave UV doesn't exist naturally on earth and only exists here when its manufactured, such as with a shortwave light. The sun and stars emit it, but it's blocked by the earth's atmosphere.

[steve B]

Originally Posted by drcy

Don't stare directly at the light (as in shine it in your eyes), but blacklights are no more dangerous, and perhaps even less, than sunlight (which contains UV light). Sunlight, of course, can cause cancer if you're in it too long.

Blacklight is longwave UV-- that's what you have and is the most benign. Shortwave UV (which you don't have) is the more dangerous. However, even then, collectors are just using shortwave UV for a relatively short duration and shining it on objects not themselves, so it won't cause harm.

Shortwave UV lights are a lot more expensive that longwave, which is why I know what you have (at those prices) are the longwave.

An interesting factoid is that shortwave UV doesn't exist naturally on earth and only exists here when its manufactured, such as with a shortwave light. The sun and stars emit it, but it's blocked by the earth's atmosphere.

One of the ones sold for Stamp collectors that has both long and shortwave will eventually be handy. Some things react to both, some only one or the other.
I priced out replacing my old dual wave light It's on the list of stuff to repair now.

[Stampsfan]

Originally Posted by samosa4u

... Anyhow, I see there is a sticker on the back of the package which says the following:

WARNING:
This product can expose you to chemicals including DEHP, which is known to the State of California to cause cancer and birth defects or other reproductive harm. For more information go to www.P65Warnings.ca.gov.

What exactly is DEHP? Is it really that bad? And why does it only mention California?

As long as you don't use them in CA, you should be fine.

[drcy]

Originally Posted by Stampsfan

As long as you don't use them in CA, you should be fine.

+1