Any tips for shooting macro under LW UV light?

Docrwm · 10-05-2012, 10:58 AM

My son has a science project due and he decided to learn about phosphorescent rocks. We've pulled together a few samples and I've been trying to photograph them under a Long-Wave UV light. The light we have is a medical UV light for disinfecting, because it was readily available. One problem is that it puts out a blue visible light to help the user guide the application of the invisible UV. The background is a piece of white copier paper. Anybody have experience with this sort of photography and want to share their wisdom?

Nass · 10-05-2012, 11:03 AM

Dunno, I think the blue kind of gives it context if you know what I mean. If you don't like it, are there not any visible light cutoff filters you could purchase from Baader or something?

Docrwm · 10-05-2012, 11:06 AM

Originally posted by Nass

Dunno, I think the blue kind of gives it context if you know what I mean. If you don't like it, are there not any visible light cutoff filters you could purchase from Baader or something?

There are built in electronic filters in the K-5 and I suppose through PS as well. I need to go research their use in situations like this, thanks.

RoxnDox · 10-05-2012, 11:07 AM

I agree, I rather like the effect with the blue light... Great shots, too. Nice colors!

Jim

enoeske · 10-05-2012, 11:54 AM

Can you stick a neutral card in there and manually white balance? Not sure what that would do to the colors. The blue does look pretty cool though.

Buschmaster · 10-05-2012, 11:56 AM

I don't like the blue.

Ok fine, I like it, but I'll play devils advocate.

I'd be very curious to see these same shots if you tried to balance it, even if they may be better/worse/same, it would be interesting to see.

I echo enoeske's sentiment of using a neutral card, otherwise, let us know what you find with the PS filters

Nass · 10-05-2012, 01:59 PM

The other way is CS4 > image > adjustments > channel mixer > output channel to blue > blue slider to zero. Black backgrounds though.

**crewl1** · 10-05-2012, 02:04 PM

Originally posted by Nass

Black backgrounds though

I was going to suggest the black fabric background. You will find that even black fabric may have certain fibers that are reactive to UV, so you will need to experiment.

Docrwm · 10-05-2012, 02:27 PM

Originally posted by crewl1

I was going to suggest the black fabric background. You will find that even black fabric may have certain fibers that are reactive to UV, so you will need to experiment.

I tried the black background first but the one I have with my macro kit is velvet and ALL the lint G-L-O-W-S something fierce. I kinda like the blue too but since I see most photos online of florescent rocks with a solid black background that was my original goal. Perhaps this is better.

Not a Number · 10-06-2012, 12:53 AM

How about some flat black spray paint on the paper/card? You can get various UV lights at automotive parts stores - dye is added to various systems to detect leaks in transmission, oil, and AC. I don't know how much visible light they give out though.

BrianR · 10-06-2012, 05:17 AM

No experience with UV, but you could try separating the rock from the background by 'suspending' it on a piece of glass. With your UV light placed directly above and no other light sources, reflections won't be much of a problem and you can make sure whatever background is visible through the glass is far enough away from your UV light to be rendered black (or blocked off from being hit by the UV light). All dust will show up though.

Or put the rock on a thin pedestal, like a fat piece of doweling (make sure it's secure or at least has something nice and cushy in the event it falls off). Again with the UV light directly above the rock, the pedestal will be rendered black provided it's shaded by the rock, make sure your background is far enough away to also be rendered black (or blocked off from being hit by the UV light). Even if it's not, you can remove the pedestal with photoshop fairly easily as it would only be a small edge you'd have to deal with.

Or a variant on the pedestal, but shoot from directly above so that the pedestal isn't visible at all from the cameras viewpoint. Have the UV light to the side, and block it off from hitting the background (your floor) to keep it black. This might take some space and/or a ladder.

Essentially you want find a way to separate the rock from the background to let you control how much light falls on the background relative to the rock.

Docrwm · 10-06-2012, 07:47 AM

Originally posted by BrianR

No experience with UV, but you could try separating the rock from the background by 'suspending' it on a piece of glass. With your UV light placed directly above and no other light sources, reflections won't be much of a problem and you can make sure whatever background is visible through the glass is far enough away from your UV light to be rendered black (or blocked off from being hit by the UV light). All dust will show up though.

Or put the rock on a thin pedestal, like a fat piece of doweling (make sure it's secure or at least has something nice and cushy in the event it falls off). Again with the UV light directly above the rock, the pedestal will be rendered black provided it's shaded by the rock, make sure your background is far enough away to also be rendered black (or blocked off from being hit by the UV light). Even if it's not, you can remove the pedestal with photoshop fairly easily as it would only be a small edge you'd have to deal with.

Or a variant on the pedestal, but shoot from directly above so that the pedestal isn't visible at all from the cameras viewpoint. Have the UV light to the side, and block it off from hitting the background (your floor) to keep it black. This might take some space and/or a ladder.

Essentially you want find a way to separate the rock from the background to let you control how much light falls on the background relative to the rock.

Good ideas. I recall the lecture I went to a few weeks ago with one of the top rock photographers (don't laugh many of his shots are STUNNINGLY Beautiful) and he said he uses non-reflective glass from picture frames to place the rock on and then hands a colored piece of paper from the back of it to give a pleasant and controlled background to the image.

**TER-OR** · 10-08-2012, 12:48 PM

The glass idea is good - put some distance between the background and subject.
Also, fix your focus under full-spectrum light, then switch. The images might be a little underexposed, which probably won't hurt you once they're adjusted in PP.
You should be able to give a nice DOF, and if you really want to explore that you can get an image-stacking program.

Docrwm · 10-08-2012, 01:00 PM

Originally posted by TER-OR

The glass idea is good - put some distance between the background and subject.
Also, fix your focus under full-spectrum light, then switch. The images might be a little underexposed, which probably won't hurt you once they're adjusted in PP.
You should be able to give a nice DOF, and if you really want to explore that you can get an image-stacking program.

Thanks Terry. I'm getting more interested in this kind of Macro photography. I'm using my M50 amd M100 macros for this and trying different wavelengths of UV light. So far the Long Wave is producing the most vivid results - although it poses the greatest health hazards and requires the most caution in using it.

**TER-OR** · 10-09-2012, 05:41 AM

IIRC you can block the UV with a bit of plexiglass - you may want to research that, and build a custom light box for a few bucks which will let you photograph and keep your eyes healthy. The best UV for this purpose is the dangerous type. My dad had (probably still has) an old mineral light which was a lot of fun to play with. I bet you can find one of those pretty inexpensively, too.

10-05-2012, 10:58 AM	#1
Docrwm Veteran Member Join Date: Sep 2010 Location: Somewhere in the Southern US Photos: Gallery \| Albums Posts: 12,285	Any tips for shooting macro under LW UV light? My son has a science project due and he decided to learn about phosphorescent rocks. We've pulled together a few samples and I've been trying to photograph them under a Long-Wave UV light. The light we have is a medical UV light for disinfecting, because it was readily available. One problem is that it puts out a blue visible light to help the user guide the application of the invisible UV. The background is a piece of white copier paper. Anybody have experience with this sort of photography and want to share their wisdom?

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10-05-2012, 11:03 AM	#2
Nass Veteran Member Join Date: Aug 2009 Location: The British Isles Photos: Gallery Posts: 2,402	Dunno, I think the blue kind of gives it context if you know what I mean. If you don't like it, are there not any visible light cutoff filters you could purchase from Baader or something?

10-05-2012, 11:06 AM	#3
Docrwm Veteran Member Join Date: Sep 2010 Location: Somewhere in the Southern US Photos: Gallery \| Albums Posts: 12,285 Original Poster	Originally posted by Nass Dunno, I think the blue kind of gives it context if you know what I mean. If you don't like it, are there not any visible light cutoff filters you could purchase from Baader or something? There are built in electronic filters in the K-5 and I suppose through PS as well. I need to go research their use in situations like this, thanks.

10-05-2012, 11:07 AM	#4
RoxnDox Pentaxian Join Date: May 2007 Location: Gig Harbor, Washington, USA, Terra Photos: Gallery \| Albums Posts: 4,494	I agree, I rather like the effect with the blue light... Great shots, too. Nice colors! Jim

10-05-2012, 11:54 AM	#5
enoeske Veteran Member Join Date: Jul 2009 Location: Surprise, Az Photos: Gallery Posts: 2,136	Can you stick a neutral card in there and manually white balance? Not sure what that would do to the colors. The blue does look pretty cool though.

10-05-2012, 11:56 AM	#6
Buschmaster Veteran Member Join Date: Dec 2006 Location: Minnesota Posts: 806	I don't like the blue. Ok fine, I like it, but I'll play devils advocate. I'd be very curious to see these same shots if you tried to balance it, even if they may be better/worse/same, it would be interesting to see. I echo enoeske's sentiment of using a neutral card, otherwise, let us know what you find with the PS filters

10-05-2012, 01:59 PM	#7
Nass Veteran Member Join Date: Aug 2009 Location: The British Isles Photos: Gallery Posts: 2,402	The other way is CS4 > image > adjustments > channel mixer > output channel to blue > blue slider to zero. Black backgrounds though.

10-05-2012, 02:04 PM	#8
crewl1 Site Supporter Join Date: Jul 2010 Location: Los Angeles, CA Photos: Gallery \| Albums Posts: 9,807	Originally posted by Nass Black backgrounds though I was going to suggest the black fabric background. You will find that even black fabric may have certain fibers that are reactive to UV, so you will need to experiment.

10-05-2012, 02:27 PM	#9
Docrwm Veteran Member Join Date: Sep 2010 Location: Somewhere in the Southern US Photos: Gallery \| Albums Posts: 12,285 Original Poster	Originally posted by crewl1 I was going to suggest the black fabric background. You will find that even black fabric may have certain fibers that are reactive to UV, so you will need to experiment. I tried the black background first but the one I have with my macro kit is velvet and ALL the lint G-L-O-W-S something fierce. I kinda like the blue too but since I see most photos online of florescent rocks with a solid black background that was my original goal. Perhaps this is better.

10-06-2012, 12:53 AM	#10
Not a Number Moderator Join Date: Mar 2012 Location: Venice, CA Posts: 10,525	How about some flat black spray paint on the paper/card? You can get various UV lights at automotive parts stores - dye is added to various systems to detect leaks in transmission, oil, and AC. I don't know how much visible light they give out though.

10-06-2012, 05:17 AM	#11
BrianR Veteran Member Join Date: Dec 2010 Location: Ontario Photos: Gallery Posts: 3,332	No experience with UV, but you could try separating the rock from the background by 'suspending' it on a piece of glass. With your UV light placed directly above and no other light sources, reflections won't be much of a problem and you can make sure whatever background is visible through the glass is far enough away from your UV light to be rendered black (or blocked off from being hit by the UV light). All dust will show up though. Or put the rock on a thin pedestal, like a fat piece of doweling (make sure it's secure or at least has something nice and cushy in the event it falls off). Again with the UV light directly above the rock, the pedestal will be rendered black provided it's shaded by the rock, make sure your background is far enough away to also be rendered black (or blocked off from being hit by the UV light). Even if it's not, you can remove the pedestal with photoshop fairly easily as it would only be a small edge you'd have to deal with. Or a variant on the pedestal, but shoot from directly above so that the pedestal isn't visible at all from the cameras viewpoint. Have the UV light to the side, and block it off from hitting the background (your floor) to keep it black. This might take some space and/or a ladder. Essentially you want find a way to separate the rock from the background to let you control how much light falls on the background relative to the rock.

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10-06-2012, 07:47 AM	#12
Docrwm Veteran Member Join Date: Sep 2010 Location: Somewhere in the Southern US Photos: Gallery \| Albums Posts: 12,285 Original Poster	Originally posted by BrianR No experience with UV, but you could try separating the rock from the background by 'suspending' it on a piece of glass. With your UV light placed directly above and no other light sources, reflections won't be much of a problem and you can make sure whatever background is visible through the glass is far enough away from your UV light to be rendered black (or blocked off from being hit by the UV light). All dust will show up though. Or put the rock on a thin pedestal, like a fat piece of doweling (make sure it's secure or at least has something nice and cushy in the event it falls off). Again with the UV light directly above the rock, the pedestal will be rendered black provided it's shaded by the rock, make sure your background is far enough away to also be rendered black (or blocked off from being hit by the UV light). Even if it's not, you can remove the pedestal with photoshop fairly easily as it would only be a small edge you'd have to deal with. Or a variant on the pedestal, but shoot from directly above so that the pedestal isn't visible at all from the cameras viewpoint. Have the UV light to the side, and block it off from hitting the background (your floor) to keep it black. This might take some space and/or a ladder. Essentially you want find a way to separate the rock from the background to let you control how much light falls on the background relative to the rock. Good ideas. I recall the lecture I went to a few weeks ago with one of the top rock photographers (don't laugh many of his shots are STUNNINGLY Beautiful) and he said he uses non-reflective glass from picture frames to place the rock on and then hands a colored piece of paper from the back of it to give a pleasant and controlled background to the image.

10-08-2012, 12:48 PM	#13
TER-OR Site Supporter Join Date: Apr 2009 Location: Dundee, IL Photos: Gallery \| Albums Posts: 6,699	The glass idea is good - put some distance between the background and subject. Also, fix your focus under full-spectrum light, then switch. The images might be a little underexposed, which probably won't hurt you once they're adjusted in PP. You should be able to give a nice DOF, and if you really want to explore that you can get an image-stacking program.

10-08-2012, 01:00 PM	#14
Docrwm Veteran Member Join Date: Sep 2010 Location: Somewhere in the Southern US Photos: Gallery \| Albums Posts: 12,285 Original Poster	Originally posted by TER-OR The glass idea is good - put some distance between the background and subject. Also, fix your focus under full-spectrum light, then switch. The images might be a little underexposed, which probably won't hurt you once they're adjusted in PP. You should be able to give a nice DOF, and if you really want to explore that you can get an image-stacking program. Thanks Terry. I'm getting more interested in this kind of Macro photography. I'm using my M50 amd M100 macros for this and trying different wavelengths of UV light. So far the Long Wave is producing the most vivid results - although it poses the greatest health hazards and requires the most caution in using it.

10-09-2012, 05:41 AM	#15
TER-OR Site Supporter Join Date: Apr 2009 Location: Dundee, IL Photos: Gallery \| Albums Posts: 6,699	IIRC you can block the UV with a bit of plexiglass - you may want to research that, and build a custom light box for a few bucks which will let you photograph and keep your eyes healthy. The best UV for this purpose is the dangerous type. My dad had (probably still has) an old mineral light which was a lot of fun to play with. I bet you can find one of those pretty inexpensively, too.