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  #1  
Old 01-29-2008, 11:38 PM
Runs With Scissors Runs With Scissors is offline
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Does semen show up under a black light?

A friend and I were indoors at a place...it was dark, but "black lit." He said the glowing spots on my t-shirt were semen stains. I say no way, I washed it.

What say you?
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  #2  
Old 01-29-2008, 11:44 PM
Pullet Pullet is offline
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So...you haven't found the answer to this experimentally yet?

Pullet
*A girl*
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Old 01-29-2008, 11:44 PM
Runs With Scissors Runs With Scissors is offline
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Aaargh...took too long to edit...

It should read like this:

A friend and I were indoors at a place...it was dark, but "black lit." He said the glowing spots on my t-shirt were semen stains. I say no way; I washed it.

And that's the main question...does semen wash out of t-shirts after one typical wash in a washing machine?

What other (common) things might have caused the "blacklighted" stains?

Inquiring minds
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  #4  
Old 01-29-2008, 11:46 PM
Runs With Scissors Runs With Scissors is offline
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Quote:
Originally Posted by Pullet
So...you haven't found the answer to this experimentally yet?

Pullet
*A girl*

I *would* but 1978 called and asked for my black light back

Seriously, though, if I had one I'd perform the test...all in the name of science
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  #5  
Old 01-29-2008, 11:51 PM
Pullet Pullet is offline
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You can get a new blacklight for like $12 at Walmart.

It's all in the name of science! Do it!
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  #6  
Old 01-29-2008, 11:52 PM
x-ray vision x-ray vision is offline
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Quote:
What other substances glow under a black light?

Urine, porphyrin, semen, sperm and saliva fluoresce under a blacklight.
http://www.ratbehavior.org/BlackLight.htm
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  #7  
Old 01-29-2008, 11:57 PM
Joey P Joey P is offline
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I'd like to reiterate something I've mentioned over and over. People always think all the stains on the comforter/tshirts/walls etc etc that glow under a black light are seman. Well, laundry detergent glows also. The stains on your tshirt or probably just left over laundry detergent.
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  #8  
Old 01-30-2008, 12:01 AM
Chronos Chronos is offline
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Almost any organic material will glow, to some extent, under a black light. The stains on your shirt could equally well have been drool, or food, or blood, or possibly sweat (I'm not sure about that one). You know better than we would how recently you would have been in contact with any of those substances.
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  #9  
Old 01-30-2008, 12:16 AM
Wile E Wile E is offline
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I heard club soda glows, too. Did you have something with club soda that you spilled on yourself? Was this a club that stamps your hand so you can get back in if you leave? Because they usually use a fluorescent ink and if you rubbed it on your shirt then it would glow. Highlighter ink also glows.
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  #10  
Old 01-30-2008, 04:38 AM
Harmonix Harmonix is offline
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I second the laundry detergent Idea.

Too lazy to find a cite right now, but I believe Modern Laundry detergent contains phosphorous to 'make your whites whiter and your colors brighter'. It shows up under a black light as glowing specks on your shirt.
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  #11  
Old 01-30-2008, 04:53 AM
An Gadaí An Gadaí is offline
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Also, jip stains are nearly impossible to get rid of.
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  #12  
Old 01-30-2008, 06:41 AM
Radegast Radegast is offline
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A little off topic but I encountered a bathroom in a Dublin pub that was heavily black-lit, and urine certainly flouresces.
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  #13  
Old 01-30-2008, 06:52 AM
brewha brewha is offline
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[Mitch Hedberg]
I was under the impression that that mustard stain came out.
[/MH]
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  #14  
Old 01-30-2008, 08:05 AM
Solfy Solfy is offline
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Many detergents contain additives that are UV active. They enhance the whiteness of your whites.
Without having actual experimental evidence, I'd wager that most *ahem* protein based stains should come out under normal washing conditions.
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  #15  
Old 01-30-2008, 08:06 AM
flurb flurb is offline
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Do you have any reason to believe that they ARE semen stains on your shirt?
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  #16  
Old 01-30-2008, 08:10 AM
KneadToKnow KneadToKnow is offline
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Quote:
Originally Posted by flurb
Do you have any reason to believe that they ARE semen stains on your shirt?
I took the statement "No way, I washed it" as evidence to support a "yes" answer to that question.
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  #17  
Old 01-30-2008, 08:23 AM
lieu lieu is offline
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Nevermind.

Last edited by lieu; 01-30-2008 at 08:28 AM..
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  #18  
Old 01-30-2008, 08:36 AM
WhyNot WhyNot is offline
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Quote:
Originally Posted by Wile E
I heard club soda glows, too.
I don't think it's club soda, but tonic water that you're thinking of. The quinine in tonic water glows under black light. Club soda's just water and CO2, sometimes with salt or baking soda.
Quote:
Originally Posted by brewha
[Mitch Hedberg]
I was under the impression that that mustard stain came out.
[/MH]
[Once More, With Feeling]
♫They got
the mustard
OOOOOUUUUUUT!♫

♫(They got the mu-stard out!) ♫
[/Once More, With Feeling]

My vote is also for detergent. Sounds like you're packing your washing machine too full for a good rinse cycle, and it's leaving stuff behind.
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  #19  
Old 01-30-2008, 10:23 AM
Cervaise Cervaise is offline
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Maybe the cat is humping your laundry.
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  #20  
Old 01-30-2008, 10:25 AM
Mr. Slant Mr.  Slant is offline
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There was a nice Youtube video along these lines.
A young lady was at a party, dancing as you please... one of her girlfriends pulled her aside and she left.
The young lady had a bright spot spreading beneath her skirt... and glowing on the left side of her mouth...
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  #21  
Old 01-30-2008, 10:37 AM
KneadToKnow KneadToKnow is offline
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Quote:
Originally Posted by Mr. Slant
There was a nice Youtube video along these lines.
A young lady was at a party, dancing as you please... one of her girlfriends pulled her aside and she left.
The young lady had a bright spot spreading beneath her skirt... and glowing on the left side of her mouth...
There's also an episode of ER where Dr. Chen (IIRC) is found to have tell-tale stains on her sweater (IIRC). She's so dignified and indignant about the snickering, pointing out all the other things it could be, that you feel guilty about snickering along with the characters. Then at the end she throws the sweater (IIRC) away with the most guilt-ridden and ashamed expression on her face you can imagine, putting the lie to her proclamations.

It was actually very touching. And hawt, because you know ... Dr. Chen. Dirty hawt.

Last edited by KneadToKnow; 01-30-2008 at 10:38 AM..
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  #22  
Old 01-30-2008, 10:45 AM
Joey P Joey P is offline
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Quote:
Originally Posted by Mr. Slant
There was a nice Youtube video along these lines.
A young lady was at a party, dancing as you please... one of her girlfriends pulled her aside and she left.
The young lady had a bright spot spreading beneath her skirt... and glowing on the left side of her mouth...
Similar to this one
http://youtube.com/watch?v=H9md6x7JKnk
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  #23  
Old 01-30-2008, 03:00 PM
mnemosyne mnemosyne is offline
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I agree with the suggestion that it is probably laundry detergent. You'd be surprised at how much organic stuff glows under UV/Black light; in fact, the fact that many things DO fluoresce is the basis for UV/Vis spectroscopy and the most common detectors for HPLC analyses. Entire fields of chemistry/entire analytical jobs rely upon the ability of things to glow under UV, down to the point of being able to tell different molecules apart based upon it!

My diamond from my engagement ring also fluoresces blue. Very pretty!
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  #24  
Old 01-30-2008, 03:33 PM
Antinor01 Antinor01 is offline
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Cigarettes look pretty cool under black light too.
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  #25  
Old 01-30-2008, 05:04 PM
chorpler chorpler is offline
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Just to add a data point, I'll say: none of the black lights I've ever tried (four of them, from stores like Wal-Mart) have caused semen to visibly fluoresce at all. Lots of other stuff, including laundry detergent, but not semen. I always wondered if the CSI-types used some kind of special black light, or if it only glows very faintly and the purple glow from the light washes it out, or something.
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  #26  
Old 01-30-2008, 05:25 PM
KneadToKnow KneadToKnow is offline
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Quote:
Originally Posted by chorpler
Just to add a data point, I'll say: none of the black lights I've ever tried (four of them, from stores like Wal-Mart) have caused semen to visibly fluoresce at all. Lots of other stuff, including laundry detergent, but not semen. I always wondered if the CSI-types used some kind of special black light, or if it only glows very faintly and the purple glow from the light washes it out, or something.
The first time I ever heard of this forensics technique was in one of Patricia Cornwell's Kay Scarpetta novels. In that one, the light had a special name, but I don't remember it now. I'll check tomorrow at work if nobody beats me to it.
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  #27  
Old 01-30-2008, 08:13 PM
Runs With Scissors Runs With Scissors is offline
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Quote:
Originally Posted by flurb
Do you have any reason to believe that they ARE semen stains on your shirt?
That stuff gets everywhere. It's worse than ice cream in a car.
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  #28  
Old 01-30-2008, 11:04 PM
Fish Fish is offline
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I'm going to chime in here, as somebody who has been carrying around a UV-light keychain for the better part of a year: yes, it does, but so do a ton of other things, including:

Coca-Cola
white paper
some detergents
some antibacterial soaps
some Chap Stik
motor oil
antifreeze
bacteria scum in the sink

...the list goes on. Try a black light and see!
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  #29  
Old 01-31-2008, 01:05 AM
MaceMan MaceMan is offline
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OK some real experimental data: I tested it and it didn't glow under fluorescent black lights, either fresh or dried. However, I'd wager that the UV lights they presumably use for crime scenes probably utilize the more dangerous, cancer-causing UV wavelengths, which would be forbidden for general use in bars, etc, due to the fact that they easily cause sunburn, cataracts, and damage DNA.

Oh, and laundry detergents definitely glow very strongly.
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  #30  
Old 01-31-2008, 02:20 AM
si_blakely si_blakely is offline
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This would indicate that the appropriate wavelengths are not even UV

Crime-lite
Quote:
* Violet Crime-lite® with a wavelength peak of 425nm (10% bandwidth
400-430nm) for detecting blood stains and gunshot residues.
* Blue Crime-lite® with a wavelength peak of 450nm (10% bandwidth
430-470nm) for general search for body fluids.
* Blue/Green Crime-lite® with a wavelength peak of 485nm (10% bandwidth
460-510nm) for treated superglue fingerprints.
* Green Crime-lite® with a wavelength peak of 520nm (10% bandwidth
500-550nm) for DFO treated fingerprints.
The orange goggles/filters just increase contrast for the fluorescence.

Although longwave UV also seem to be used for forensic lights.

Si
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  #31  
Old 01-31-2008, 05:46 AM
WILLASS WILLASS is offline
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LSD fluoresces under a black light.........
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  #32  
Old 01-31-2008, 10:08 AM
Ichbin Dubist Ichbin Dubist is offline
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Quote:
Originally Posted by WILLASS
LSD fluoresces under a black light.........
It also makes the wallpaper inhale and exhale.
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  #33  
Old 01-31-2008, 10:50 AM
Larry Mudd Larry Mudd is offline
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Quote:
Originally Posted by WILLASS
LSD fluoresces under a black light.........
So does coffee.

Back in the eighties and nineties, when I sometimes found myself in blacklit situations where LSD was being used, I used to amuse myself by using a q-tip to apply cryptic symbols to my face in coffee. Dries invisible, and then later, under black light, you trip the hell out of your fellow heads.

Good times.
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  #34  
Old 01-31-2008, 12:04 PM
Cervaise Cervaise is offline
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Quote:
Originally Posted by MaceMan
OK some real experimental data: I tested it and it didn't glow under fluorescent black lights, either fresh or dried.
How about pan-fried?
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  #35  
Old 01-31-2008, 01:35 PM
Pullet Pullet is offline
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Quote:
Originally Posted by KneadToKnow
The first time I ever heard of this forensics technique was in one of Patricia Cornwell's Kay Scarpetta novels. In that one, the light had a special name, but I don't remember it now. I'll check tomorrow at work if nobody beats me to it.
Are you thinking of a Wood's lamp?
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  #36  
Old 01-31-2008, 02:46 PM
KneadToKnow KneadToKnow is offline
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Quote:
Originally Posted by Pullet
Are you thinking of a Wood's lamp?
At this point in my day, it will be Saturday before I can verify with the text itself, but that sounds very, very, very right.
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  #37  
Old 01-31-2008, 02:59 PM
Gfactor Gfactor is offline
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http://www.labino.com/pdf/Crime%20-%...y%20fluids.pdf

Page 2 shows examples of semen stains under UV light.

And see: http://abcnews.go.com/GMA/Health/story?id=1507794

Last edited by Gfactor; 01-31-2008 at 03:00 PM..
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