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#55299 - 01/28/03 02:34 PM A method for detecting alterations -- using a UV source or "blacklight"
MW1
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This was a topic on the comic forum, but I think it's also quite pertinent here. There was some concern among the comic denizens over the adequacy of a UV source in detecting color touches (CT's). Apparently this is a big problem with many different titles. Here is a brief summary of some of the concerns:

I've been using a black light on and off for about the last year. There are two problems I've found with using them:

  • They don't seem to be useful unless you're in a dark room. The example someone gave of looking dumb by whipping out a black light at a show--I don't think that's a concern, because even the dim lighting at most hotel convention rooms is too much light to allow you to use the black light effectively.
  • A longwave UV lamp is NOT a magic tool that makes color touch detection easy. Very slight CT doesn't just jump out at you, even under a black light. You've gotta look really closely--the CT doesn't glow like the sun or anything.

It was also noted that UV sources or blacklights can't detect black CT's.


These were some of my thoughts on the topic:

Some of the lower quality UV sources (even longwave) do not perform particularly well. I use a UVP Mineralight Lamp (Model UVGL-58). It's a multiband UV source (115 V, 60Hz, .16 amps) that operates at 254/366 NM in the UV spectrum. I purchased it from the same catalog that university physics and chemistry departments use.

Link to UVP's website

Link to UV lamp section

Using this blacklight source, I can easily detect any material alteration, no matter how small. I can also discern many chemical additives and any CT, no matter how minor. And even though black CTs do not fluoresce like other colors, they are still detectable since they often will reflect light differently.

Still, several other forum members are correct -- there is no substitute for experience, and such knowledge allows for the more effective use of any UV source.

Model UVGL-58 pictured below



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#55300 - 01/28/03 02:48 PM A followup [Re: MW1]
MW1
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If anyone is interested, I could try to take a picture to show how the altered part of a baseball card fluoresces when exposed to UV light. I'm not sure I'll be able to do it, but just let me know and I'll try.
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#55301 - 01/28/03 02:52 PM Re: A followup [Re: MW1]
vayank
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MW > Are these lights the types you find in the classified section of High Times?
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#55302 - 01/28/03 02:53 PM Re: A followup [Re: vayank]
vayank
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I would like to see such a demonstration ...
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#55303 - 01/28/03 03:35 PM Re: A followup [Re: vayank]
Lothar52
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i second
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#55304 - 01/29/03 01:36 AM Re: A method for detecting alterations -- using a UV source or "blacklight" [Re: MW1]
aconte
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I'd like to see a demo.

And I must say I'm glad you post on this board. These are great threads to read
and learn from.

aconte
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#55305 - 01/29/03 02:04 PM UV demo [Re: aconte]
MW1
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Here's the image of a well-known football card illuminated by a high-band UV source in a dimly lit environment. Note the difference in luminescence between the greenish-gold and blue areas of the background. Also, observe the difference in various areas on Lansford's hand and in the name and team banner near the bottom (the dark area is not a shadow). The darker areas reflect (no irony intended) an unaltered status, while those that "glow" indicate a non-original surface (e.g., re-coloring or chemically treated).

Under typical, non-UV lighting, this card appears completely normal -- even under close visual inspection.


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#55306 - 01/29/03 02:12 PM Re: UV demo [Re: MW1]
Lothar52
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nice!!!!!!!!!!!
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#55307 - 01/29/03 02:58 PM Re: UV demo [Re: MW1]
Arty
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Could you post a picture of this card under typical lighting. I think they would also like to see those pics on comics board.
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#55308 - 01/29/03 03:22 PM Visible light demo [Re: Arty]
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As a footnote to my previous post, I would like to point out that the UV demo you see does not adequately reflect the high degree of contrast present between altered and unaltered areas of the card. An in-person demonstration would be far more effective.

Here is an image of the same card under normal lighting conditions (Note: this card has been professionally restored by Dick Towle of Hammond, New York (Gone With The Stain)).


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#55309 - 01/30/03 12:21 AM Re: Visible light demo [Re: MW1]
srs1a
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Wow! Super demonstration!!! thank-you MW1.




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#55310 - 01/30/03 05:35 AM Re: Visible light demo [Re: srs1a]
Anonymous Unregistered



U DA BOMB MW !

I'm sure this helped a lot of collectors. vwtdi


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#55311 - 01/30/03 01:31 PM Re: Visible light demo
Anonymous Unregistered



Nice post. As a side note, UV wavelength LEDs have recently been introduced into the marketplace. I haven't obtained one yet, but it could potentially offer a "do it yourself", low cost option if the brightness and uniformity is sufficient for illuminating cards. Currently they're being used for dentistry (catalyst to harden filling material).
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#55312 - 02/08/03 03:14 PM Re: UV demo [Re: MW1]
povertyrow
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Here's the image of a well-known football card illuminated by a high-band UV source in a dimly lit environment.

Interesting. What was used to photograph the UV pic?
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#55313 - 02/10/03 03:10 PM Re: UV demo [Re: povertyrow]
MW1
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povertyrow,

I used a Nikon950 with spot metering, no flash, in close-up mode and a slow shutter speed.

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#55314 - 02/11/03 06:21 PM Re: UV demo [Re: MW1]
povertyrow
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I used a Nikon950 with spot metering, no flash, in close-up mode and a slow shutter speed.

OK - lemme back up a bit. Was a pro photographer in the 70's (2 1/4 x2 1/4 and 4x5).

What I mean for this type of photography is:

What light source

What film type?

Any special filters?

Thanks!
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#55315 - 02/13/03 02:58 AM Re: UV demo [Re: MW1]
hammer
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MW, I'm not following you here. Which are the specific areas on the card imaged above, that the blacklight is indicating as redone, altered, or bleached?
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#55316 - 02/13/03 03:32 AM Re: UV demo [Re: povertyrow]
MW1
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What light source?

Good question! I collected 10 different samples of incident light using a standard light meter. Then, using the following equation for irradiance (14.1),



where d represents the diffusiveness of each wall, I was able to derive a value of .05 Watts per meter squared. Hey, I'm only kidding!

I had the lights off in the room where I took the photograph. Two rooms over -- approximately 50-60 feet away, I had the lights on (standard fluorescent office lighting). There may have also been a small amount of light diffusing through the blinds on the windows.


What film type?

128 MB Lexar High-Speed Compact Flash Card.


Any special filters?

None. Using my medium format (film) camera, however, I would probably throw on a clear filter and a polarizer to get the image to look right -- but I really haven't used anything but digital cameras for over a year now, so who knows. I'm sure you have a better idea about this than I do.

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#55317 - 02/13/03 03:39 AM Re: UV demo [Re: hammer]
MW1
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hammer,

The contrast between light and dark is not as great as it would visually appear in person. Suffice it to say that the darker areas represent "unaltered" portions of the card and lighter areas represent sections of the card where "alterations" have been performed. With the UV source I used, there are also slight graduations in the lightened areas -- probably due to the type of alteration that was done. In my experience, this is fairly typical for most professional grade work.

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#55318 - 02/13/03 03:47 AM Re: UV demo [Re: MW1]
MW1
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Followup:

hammer,

A fair portion of the card has been altered in some fashion (micro-trimmed, chemically treated, re-inked, etc.). With the exception of some interior portions, not a whole lot of the card remains untouched. If I were to take a similar picture of an unaltered 1952 Bowman Large Lansford, the only thing you would see is a darkened image on your screen and a perhaps a slight magenta tint. Hope that helps!

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#55319 - 02/13/03 09:11 AM Re: UV demo [Re: MW1]
hammer
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I read you. I was approaching the card from the aspect of thinking that only a few things were done rather than the majority of the card tweaked!! Thank you MW!!
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#55320 - 02/14/03 01:40 PM Re: UV demo [Re: MW1]
Rickdogg
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WOW that is awesome. We need those for comics!
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#55321 - 02/14/03 05:22 PM Re: UV demo [Re: MW1]
povertyrow
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I was able to derive a value of .05 Watts per meter squared.

Actually I calculated .049831 WPM!
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