Jump to content
UltravioletPhotography

Infrared Fluorescence


Damon

Recommended Posts

Illuminate subject with either UV or Visible light in the dark.

Photograph subject thru IR-pass filter.

 

If you get anything it will be called UV-induced Infrared Fluorescence or Visible-induced Infrared Fluorescence.

 

I thought maybe I got some once. It's posted somewhere. Search on "Infrared Fluor" or "IR Fluor".

Link to comment

Well, you know what I've always said -- you must filter both your illumination and your lens in order to assert you are performing UV-induced Visible Fluorescence photography or UV-induced Infrared Fluorescence photography. Even in the dark.

 

Filtered UV-source + Unfiltered Lens in the dark = UV-induced Fluorescence only. Because you might accidentally be recording some IR fluor. stray reflected wavelengths. This may be unlikely, I grant you -- but I don't think any of us have the experience to rule it out for some subjects especially when we are using a modified camera or a camera with weak internal filtration.

 

Unfiltered UV-source + Filtered Lens in the dark = Mostly-UV-induced Visible Fluorescence or Mostly-UV-induced Infrared Fluorescence ?? I don't really know what the proper designation would be for this scenario. As long as the photographer notes that their UV illumination is unfiltered, I've been letting it slide because a good strong filter on the lens ensures that you are capturing mostly either Visible or Infrared Fluorescence. This answers your 2nd question Damon. If source illumination is not pure, say so. And ensure that you have the proper filter on the lens to claim either Vis or IR fluor.

 

Unfiltered Illumination + Unfiltered Lens? I'd call this throwing light on the subject and seeing what sticks. But then I am sometimes a bit of a purist. Ymmv. :lol:

 

BTW, I'm pretty sure that with plants & flowers we would never see anything except shortwaveInput/longwaveOutput type of Fluorescence. In other words you probably cannot shine any IR on a posy and hope to get any UV fluor because the energy state would have to go up. Pretty hard to do.

 

(Corrections always welcomed if I get something wrong with this stuff.)

 

EDIT: 17 Feb 2015

Corrected one error.

Added phrase 'in the dark' in 2 places.

Link to comment

Thanks!

Ok, so bear with me as I think I went hillbilly somewhere down there:

 

Re: Unfiltered UV-source + Filtered Lens = Mostly-UV-induced Visible Fluorescence or Mostly-UV-induced Infrared Fluorescence ??

So by performing that experiment with the Hoya RM72 on top of the UV-IR cut while hitting the subject with 6 blak-rays and nothing at all coming through--Doesn't that show that I am at least not recording UV-induced Infrared Fluorescence? Or does that experiment just tell me the IR from the Blak-Rays is not getting through? I suppose I could put the Baader U on there over top of the UV-IR cut and make sure UV is not also getting through.

Ya know, after all this time, I still spell fluorescence wrong--so annoying.

 

If filtration is never a brick wall (paraphrasing) as Bjørn stated recently, how can one ever claim any of these types of fluorescence? If we can only claim increased probabilities of something, then that's what it is.

What I'm getting at is that filtering the source and the lens is good but I don't see how it is any better than just filtering it on the lens as neither one can be demonstrated to be perfect.

 

When we use a Baader U filter for UV shots in full sunlight--are we not trying to filter the source and the lens at the same time? I can't filter the sun with a giant filter. If my Blak-Rays are unfiltered for IR but the IR is shown to being blocked by the lens filter--then it should stand as UV-induced visible Fluorescence? Or do I need to show it's not UV-induced UV Fluorescence too? Or are you saying it could be IR induced visible fluorescence. Aaaagh! :lol:

 

 

-D

Link to comment

Damon, slow down. You are hanging yourself up here. :lol: (We've all been there.)

 

**********

 

Hoya RM72 on top of the UV-IR cut while hitting the subject with 6 blak-rays and nothing at all coming through

 

Illumination: Blak-Ray lamps (...with Woods filters? I forget how they are filtered.)

Lens: both Hoya RM72 and UV-IR Cut filter. (Do I have that right ??)

 

Result: Well, nothing.

The camera cannot record any IR passing through the IR-pass filter if the other filter on the stack is blocking IR, now, can it??

 

**********

 

When we use a Baader U filter for UV shots in full sunlight--are we not trying to filter the source and the lens at the same time?

 

Illumination: Sunlight.

Lens: Baader-U UV-pass filter.

 

Result: Reflected UV photograph - which is NOT fluorescence photography.

 

In reflected UV photography you are trying to capture the UV which is not absorbed by a subject, that is, the UV which hits the subject and changes direction, that is, the UV which is reflected off of a subject. Visible and IR light is also reflected off the subject, but a strong filter on the lens ensures that you do not record that.

 

In fluorescence photography you are trying to capture the emission of lower-energy, longer-waved light which occurs when higher-energy, shorter-waved light is absorbed and causes a state change in atoms or molecules. So to control that state change, you must be sure to filter the illumination source. And to ensure you are recording only one kind of light emission, you must be sure to filter the lens.

 

*********

 

We are not practicing precision fluorescent photography here because we are not using narrowband filters on either source or lens. Those kinds of filters are expensive and would have little use outside a lab setting.

Link to comment

Thanks so much for being patient. It's coming to me. :)

 

Re: Result: Well, nothing.

The camera cannot record any IR passing through the IR-pass filter if the other filter on the stack is blocking IR, now, can it??

I only tried this upon request and you appeared to show interest. :P "I second Col's request for an attempt at inducing IR fluor. It will act as a test of your system - or might produce a surprise."

 

Re: In reflected UV photography you are trying to capture the UV which is not absorbed by a subject

What about for ex. a Rhudbekia Bulls-eye?

 

Re: In fluorescence photography you are trying to capture the emission of lower-energy...

Ok I think I understand that now. I technically need to filter the Blak-Rays.

So the UV energy of my Blak-Ray may affect the state change in atoms/molecules differently on a subject than their Infrared energy would, therefore the emission might be different--which is what we are trying to capture. Hitting a subject with both UV and IR may make a combination of states thus possibly emitting a hybrid fluorescence? If you could capture it. Or maybe they are separate all together and wouldn't mix their emissions.

 

One last time: :D

Re: So to control that state change, you must be sure to filter the illumination source. And to ensure you are recording only one kind of light emission, you must be sure to filter the lens.

If I use Blak-rays which have woods filters, UV & IR are coming out (Yes I know there a 2 possible minor leaks Shane pointed out)---

1. Hits flower...molecules change state...could be UV induce Vis Fluor molecules or UV induced IR Fluor molecules.

2. Lens has UV-IR-Cut filter which does not let in IR from Blak-Rays. IR fluor (if produced) can't get through, therefore picture must be UV induced Vis Fluor

 

I would start thinking more about UV-induced IR fluorescence if I could see some examples of it.

It would stink if after taking all these pics, and future ones, I can't even say what they are (technically).

I thought you said somewhere that a flower in unlikely to show UV Induced IR fluor.

 

 

Ok that's enough hanging myself tonight !! :lol: :blink: :o

 

-D

Link to comment
I would start thinking more about UV-induced IR fluorescence if I could see some examples of it.

It would stink if after taking all these pics, and future ones, I can't even say what they are (technically).

I thought you said somewhere that a flower in unlikely to show UV Induced IR fluor.

 

Posted in Jan 2015 - IR fluorescence of geranium leaves (Mg porphyrin i.e. chlorophyll).

IR fluorescence excited by blue-green light centered around 490nm but UV works just as well for porphyrins

http://www.ultravioletphotography.com/content/index.php/topic/1171-food-under-uv-induced-fluorescence/page__view__findpost__p__6217

Link to comment

Don't get out the rope yet Damon! You are almost there.

 

Irregardless of what kind of fluorescence you are trying to image the fundamentals are the same.

 

post-24-0-22172500-1424187750_thumb.gif

 

The above diagram is for UVIVF, but the concept is the same for any excitation/emission paring.

 

The critical thing is that the combination of filters render the camera completely blind to the excitation source but not the fluorescent emission.

 

In a pure sense nonfluorescent objects should be invisible/black and only visible if reflecting adjacent fluorescent emission.

 

The example in the diagram assumes complete darkness and will not necessarily be what you see, even if your goggles are made of the same barrier filter, because the camera may see wavelengths you might not such as IR.

Link to comment

Re: Result: Well, nothing.

The camera cannot record any IR passing through the IR-pass filter if the other filter on the stack is blocking IR, now, can it??

I only tried this upon request and you appeared to show interest. :lol: "I second Col's request for an attempt at inducing IR fluor. It will act as a test of your system - or might produce a surprise."

 

OK, back up here. Let's go to the definitions. If you want to capture either fluorescence-IR or 'ordinary' reflected-IR photograph, you place only one filter -- an IR-Pass filter -- on your taking lens.

 

If I missed it back there that you were using both an IR-pass and an IR-block simultaneously, then my apologies. But you have to understand that it simply does not occur to me that anyone would try to simultaneously pass & block IR light. Ya know what I mean? This is kinda like, well, common sense?

 

So what we were wanting to actually have you test back there, was the amount of IR those Blak-Rays might be putting out. Go into the dark UV-shack, illuminate one of your unfried flowers under the Blak-Rays, put an IR-pass filter on your lens and see if you record any IR output from the BRs. Then if you are still sufficiently unfrozen, remove the IR-pass filter and place a good UV/IR filter on the lens and see if you record any Visible output from the BRs.

 

But it's all good, Damon. We were once all beginners. Don't go thinking that we don't all make mistakes sometimes or always know what we are talking about. Sometimes we screw up too. I pretty much manage to do it daily one way or t'other. :blink:

 

***************************

 

Hitting a subject with both UV and IR may make a combination of states thus possibly emitting a hybrid fluorescence? If you could capture it. Or maybe they are separate all together and wouldn't mix their emissions.

 

Mutlple emissions can happen. Remember the discussion of chlorophyll? Note that when you read the scientific papers or books about fluorescence in specific subjects, you will find that the exciting wavelength(s) and the emitted wavelength(s) are very precisely known. However, when we are doing this Fluor Fotografy, we are blundering about in quite a broadband way and we have no idea at all of what the precise excitation/emission wavelengths are. So the least we can do is to try to excite with UV-only and record Vis-only or IR-only as best we can.

 

Look, it is not easy or cheap. I have a small Baader-U diffuser filter (i.e., not cheap) for my Nichia 365nm torch in order to try to cut out any stray violet/blue wavelengths at the upper edge of the Nichia band around 365nm. Is it a perfectly filtered excitation source? Probably not perfectly filtered, but filtered well enough for these generic fluor fotos we capture here.

Link to comment

So by performing that experiment with the Hoya RM72 on top of the UV-IR cut while hitting the subject with 6 blak-rays and nothing at all coming through--Doesn't that show that I am at least not recording UV-induced Infrared Fluorescence?

 

I saw where you said you stacked the 720nm longpass filter on the UV-IR Cut and was not sure that was't a typo.

 

To answer your question, no, all that proved is that the UV-IR cut blocks >720nm Blak-Ray output that is reflected off your subject.

 

It is an excellent negative control to confirm you are not imaging >720nm when you employ the UV-IR cut in that manner.

Link to comment

If I use Blak-rays which have woods filters, UV & IR are coming out (Yes I know there a 2 possible minor leaks Shane pointed out)---

1. Hits flower...molecules change state...could be UV induce Vis Fluor molecules or UV induced IR Fluor molecules.

2. Lens has UV-IR-Cut filter which does not let in IR from Blak-Rays. IR fluor (if produced) can't get through, therefore picture must be UV induced Vis Fluor

 

1) Yes, multiple fluorescent emissions are possible. Chlorophyll, as mentioned, is one example. It fluoresces visibly around 673nm and infrared-ly around 735nm.

LINK: http://www.ultraviol...ndpost__p__4900

 

2) Blak-Rays + UV/IR Cut Filter ==> Yes you would be recording Visible fluorescence only if the cut filter is strong enough. And yes it is very likely only UV-induced because USUALLY the state change is induced short-to-long. If IR from a Blak-Ray were going to induce Vis fluorescence, we would all be very amazed. But you still need to mention how the Blak-Rays are filtered or not. I don't work with these lamps so I don't have any real feel for side effects from stray IR or stray Vis (if any).

 

I will definitely try not to be such a purist about the UVIVF labeling as long as the illumination source emits no Visible and as long as the taking lens is properly filtered - even in the dark. :lol:

 

*******************************************

 

We have lots of folks here who help keep each other on the straight & narrow path of proper labeling and rigorous (enough) experimental efforts. Thank you to EVERYONE !!!!!

Link to comment

Damon,

 

If you refer to the Wood's Glass transmission plot I posted in your other thread you will note that the secondary peak is ~720nm. If you use a RG665 or RG695 longpass filter with and without your UV-IR cut you will be able to access how much of this long wavelength emission is impacting your UVIVF work.

Link to comment

"with and without your UV-IR cut" ????????

 

It is simply not occuring to me why you would stack an rg695 with an uvir cut?

 

I must be missing something. :lol:

Won't be the 1st time...........

Link to comment

Andrea,

Just the scientist in me being diligent with +/- controls, without shows what is there & with shows that it is effectively blocked. I am thinking there may be a slight overlap of the secondary Blak-Ray emission peak within the camera's red response given the magnitude of illumination being used.

Link to comment

lens + IR-pass = IR-pass

 

lens + IR-block = IR-block

lens + IR-pass + IR-block = IR-block

How are these last two different?

 

I'm still not getting something here.

Link to comment

The Blak-Rays also put out Visible light?

 

****

 

I have gotten utterly lost in who is using which filter for what.

 

I think that above Damon was using a 720nm IR-pass. So I was not sure why stacking it with the UV/IR cut filter made sense.

 

John is suggesting a 665nm or 695nm IR+Vis Pass. Although for the 695nm the Vis-pass portion is not very wide.

With these filters you prolly do need a secondary stack test to cut the vis?

 

whew!

Link to comment

Andrea,

It is my understanding that the Blak-Ray is an intermediate or high pressure Hg lamp filtered with Wood's Glass type filter. This does not exclude the possibility of my being wrong on that point. I have been trying to find one locally I might borrow so that I could make a proper spectral irradiance scan.

 

If my understanding is correct, much like a Xenon flash filtered with only a UG-11 or Kopp9863 type filter, the emission overlaps a bit into the blue and also has a secondary emission at ~720, both of which are within the passband of the UV-IR Cut filter. The use of a UV-Deep Blue blocking filter such as a GG-420 takes care of the short wavelength overlap. The Deep Red/NIR secondary emission of this lamp has been a subject of ongoing discussion. That is why some have asked for photos with an IR filter, or so I thought.

Link to comment

I am going out to my shack now but will return later. Whew is right--I will digest later and thank you.

I thought Shane has worked with Black-Rays a lot and should know the answers to your questions regarding them. If I m wrong--I apologize Shane.

If I was closer John I would drive one over. I bought a crate full from a guy for ~$100 awhile back--must have almost 15 of these things now. :)

 

-D

Link to comment

Re: So what we were wanting to actually have you test back there, was the amount of IR those Blak-Rays might be putting out. Go into the dark UV-shack, illuminate one of your unfried flowers under the Blak-Rays, put an IR-pass filter on your lens and see if you record any IR output from the BRs. Then if you are still sufficiently unfrozen, remove the IR-pass filter and place a good UV/IR filter on the lens and see if you record any Visible output from the BRs.

 

Well I already know what happens when I put an UV/IR cut on the lens and shine the B-Rays on the flowers--I get all the recent UVIVFL pics I have taken. Or do you mean I should point the B-Rays at my lens? I will try the latter as that is simple to do.

 

-D

 

-D

Link to comment

Well I already know what happens when I put an UV/IR cut on the lens and shine the B-Rays on the flowers--I get all the recent UVIVFL pics I have taken

 

oh yeah!! I forgot where we started in this Long & Winding Thread. :lol: :P :wacko:

 

We will lose all our UVIR marbles if we discuss this anymore.

 

This thread makes me rather glad that I'm currently doing UVIVF with a simple narrow(ish) band torch. It seems easier to determine what I'm actually inducing. :wacko: :blink: :) :lol:

 

I may have to throw all the towels into the ring !!!!

 

Whew !!!

 

(....really I'm having fun.....)

Link to comment

Sorry. I had a moment of UV-Induced Visible Angst back there somewhere. Or it could have been UVIV-Insanity? :)

 

*****

 

Let us list the test parameters yet once again and account for border-line leakage which I was pretty much ignoring because I think I had the idea of a B+W 093 (830nm) in my head for an IR-Pass filter. I usually think of the 695 and its friends as (IR+Vis)-Pass filters.

 

EDITS: 18 Feb 2015. Incorrect statement about Blak-Ray output removed after seeing transmission chart. Also suggested tests were clarified as suggested by next post.

 

1. Woods-filtered Blak-Ray + Baader-U UV-Pass on Lens = Test for Blak-Ray UV output and maybe a tiny bit of reflected violet/blue near the filter cut off.

 

2. Woods-filtered Blak-Ray + IR-Pass Filter on Lens = Test for Blak-Ray IR output or IR emissions and maybe a tiny bit of Vis reflection depending on where the longpass IR cuts in.

 

3. Woods-filtered Blak-Ray + Baader UV/IR Cut Filter on Lens =Damon's lovely photos which are probably 98-99%% UVIVF. This is basically a test for Blak-Ray Visible output (reflection) if any, for the flower's Visible fluorescent emission and maybe for a tiny bit of IR output (reflection) from Blak-Ray depending on where the blocking filter cuts off. (There are variations out there. The newer Baader UV/IR Cuts are tighter.)

 

4. Woods-filtered Blak-Ray + IR-Pass Filter stacked onto Baader UV/IR Cut Filter on Lens = Test for Blak-Ray output between the longpass cut-in and the blocking cut-off if there is any overlap. This would be a very narrowband test if you used the 695nm or a 715nm, for example.

 

John, help!! did I leave anything out?

Link to comment

John, help!! did I leave anything out?

 

Well, OK. I will run through it.

 

1. Woods-filtered Blak-Ray + Baader-U UV-Pass on Lens = Damon's lovely photos which are probably 98% UVIVF but might have a tiny bit of reflected violet/blue too, but we don't care because it isn't very much (at least we hope so).

 

No, Woods-filtered Blak-Ray + Baader-U UV-Pass on Lens is not = UVIVF, where V=Visible, Baader-U UV-Pass blocks UVIVF. This would be reflected UV + any Badder-U leak. I know you know - wires get crossed sometimes.

 

2. Woods-filtered Blak-Ray + IR-Pass Filter on Lens = Test for Blak-Ray IR output (mostly) and maybe a tiny bit of Vis output depending on where the longpass cuts in.

 

Yes, correct with the caveat that because the unmodified camera's internal IR blocking is also still intact one needs a shorter 645 or 695 to see all the Blak-Ray potential long wavelength contamination.

 

3. Woods-filtered Blak-Ray + Baader UV/IR Cut Filter on Lens = Test for Blak-Ray Visible output (mostly) and maybe a tiny bit of IR output depending on where the blocking filter cuts off. (There are variations out there. The newer Baader UV/IR Cuts are tighter.)

 

No, this is ~ Damon's lovely photos with whatever blue and red/NIR is within the UV-IR cut passband. Also with the with the same caveat that the unmodified camera's internal IR blocking is also still intact. Normally the UV/IR Cut would be considered redundant on an unmodified camera but perhaps not against multiple Blak-Rays and a UV/IR capable lens.

 

4. Woods-filtered Blak-Ray + IR-Pass Filter stacked onto Baader UV/IR Cut Filter on Lens = Test for Blak-Ray Visible output between the longpass cut-in and the blocking cut-off if there is any overlap. This would be a very narrowband test if you used the 695nm or a 715nm, for example.

 

Yes, looking again for overlap as in #2. Using rather a 645-695nm Red/IR filter to exclude most UVIVF while maximizing overlap with Wood's glass 2nd passband. This is where one might prefer to also shoot directly into the lamp or at a known non-fluorescent target.

 

Perhaps this image I plucked from a website will also help.

post-24-0-24101000-1424218501.jpg

Link to comment

John, I think you posted just before me so your caveats are not in my test-although I think I came to make some of the same corrections. I can put them in if you guys deem it sensible.

 

Ok here is some information after some new testing-I will use some of Andrea's initial parameters and then added some stuff.

 

These photos are unaltered raw straight from camera and converted to JPEG. Nothing was done to them. Nada. Zip.

 

The following parameters in bold were identical in all pictures in an attempt to decrease variables. I am not a scientist so if this was a dumb idea, well no worries as I am perfectly fine being the newbie pin cushion

 

Light source 6 Woods-filtered Blak-Ray lamps with new filters

Camera--Canon 1D Mark IV Unmodified

Lens--EL-Nikkor 80mm f5.6 & all photos @f5.6 iso 1600

Complete Darkness

 

--My text below is red.

--Andrea text Black

--My Sanity disappearing

 

 

1. 6 Woods-filtered Blak-Rays + Hoya RM72 IR-Pass Filter only on Lens = Test for Blak-Ray IR output (mostly) and maybe a tiny bit of Vis output depending on where the longpass cuts in.

30 s shutter speed

This was the only way I could get IR to show up using the Blak-Rays--long exposure & high iso

post-51-0-73466600-1424222052.jpg

 

2. 6 Woods-filtered Blak-Rays + Baader UV/IR Cut Filter on Lens = Test for visible fluorescence. My Baader UV/IR Cut Filter was bought in Jan 2015. That looks really blue on my HD screen. Maybe it's my monitor.

0.4 s shutter speed

post-51-0-63603300-1424222054.jpg

 

3. 6 Woods-filtered Blak-Ray + Baader U Filter only on Lens

0.6 s shutter speed

post-51-0-12009600-1424222054.jpg

 

4. 6 Woods-filtered Blak-Rays no filters at all on lens

1/5 s shutter speed

post-51-0-11172600-1424222055.jpg

 

5. 6 Woods-filtered Blak-Rays + 093 IR-Pass Filter only on Lens

30s shutter speed

post-51-0-65976600-1424222053.jpg

 

Didn't do these yet:

6. Woods-filtered Blak-Ray + Baader-U UV-Pass on Lens = Damon's lovely photos which are probably 98% UVIVF but might have a tiny bit of reflected violet/blue too, but we don't care because it isn't very much (at least we hope so). A Baader U would not let any visible light in but I can try this test if you want

 

7. 6 Woods-filtered Blak-Rays + IR-Pass Filter stacked onto Baader UV/IR Cut Filter on Lens = Test for Blak-Ray Visible output between the longpass cut-in and the blocking cut-off if there is any overlap. This would be a very narrowband test if you used the 695nm or a 715nm, for example. Did this with the 093 and got no image at all--pitch black. Which exact filter do you recommend for this test?

 

8. 6 Woods-filtered Blak-Rays + Baader UV/IR Cut Filter on Lens = Test for Blak-Ray Visible output (mostly) and maybe a tiny bit of IR output depending on where the blocking filter cuts off. (There are variations out there. The newer Baader UV/IR Cuts are tighter.)

I will shine the Blak-Ray directly at the lens with filter and see if there is anything coming through. This could be a test for visible contamination if the Blak-Rays are throwing visible light.

 

 

-D

Link to comment

Please sign in to comment

You will be able to leave a comment after signing in



Sign In Now
×
×
  • Create New...