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UltravioletPhotography

Fifty Kinds of Lint


Andrea B.

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I was prompted to look at my Snowdrop photos upon seeing Steven's lovely post earlier today: http://www.ultraviol...valis-snowdrop/

 

I found this Snowdrop fluorescence study -- full of all kinds of sparkling, blue fluorescent lint !! So I had to post this so that Mark could see that he is not the only one plagued by lint bunnies. :D

 

I had placed the Snowdrop on a paper towel to photograph it. Bad idea. Really bad idea. In addition to flower pollen lint and dirt granules lint, I have paper towel fiber lint. And probably a multitude of other household lint. The curious felines no doubt passed by as I was setting up and released a few pounds of cat hair to float ever so gracefully in the air to settle on the paper towel as a contribution to what they assumed was a Study of Lint. (I'm convinced cats can shed at will.)

 

D200-mod + UV-Nikkor 105/4.5 + Nichia UV-Led.

Torch unfiltered and Baader UV/IR-Cut filter on the lens.

f/16 for 4" @ ISO-400.

Color accuracy not attempted. (I did not have a fluor standard then.)

Snowdrop on Paper Towel, 2009

galanthusUVIndVisFluor032109wf_27035pfWithLint.jpg

 

 

I threw this file into Capture NX2 for cloning out the lint. But what was I thinking? That would have taken hundreds of clicks. Thousands, maybe! So I used some color points to try to darken the lint by color selection. Eventually I gave up on that because who knew there were 50 shades of blue fluorescence?!? I decided to simply darken the entire background -- which I suppose worked fairly well. An entirely dark background does tend to make the flower look as though it is floating in nowhere, but hey, the lint is gone. Ok, maybe a crumb or two is still left on the edge of that one petal, but I'll leave that in for the sake of veracity.

I'm going to live with this version. B)

 

Snowdrop in the Void of Space, 2009

galanthusUVIndVisFluor032109wf_27035pfDeLinted.jpg

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Not only was your battle against lint-fluorescence (LF? ;)) victorious with such a nice result, but you also touch upon a topic which leaves me conflicted every time. That is, the point of context. As it applies to most any photo, having the subject completely isolated does tend to leave one with a feeling that something, just something is missing (the 'big picture', scale, etc.). I've spent many a frustrated hour shooting UVIVF images trying to ensure they are 'pure', just to be left with, as you say, my subject floating in nowhere. Its still a battle to get myself to accept some 'contamination' not only as acceptable, but rather as contextually desirable. Perhaps if I could setup some sort of intentionally UV fluorescent context (background, etc), then I'd be able to have the context without the 'contamination'. I'll have to give that a bit more thought. Suffice it to say, I like the results of your re-work.
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(Thank you. :) )

 

It might be difficult to say what is a reasonable idea of context for a UVIVF floral signature? We shoot them in the dark. We are trying to show something never seen except under unusual illumination. So perhaps we could say that the appearance of "floating in the void" is the appropriate context for certain of our more dramatic UVIVF floral signature photographs?

 

I'm just musing here. :rolleyes: B)

 

The question of context is a certainly a legitimate one in documentary photography. For the Snowdrop above, my frustration with the Lint Problem caused me to give up altogether on showing any context. But documentary photography can also be artistic. There's nothing says you can't have a pleasing composition, beautiful lighting, nice shadows and good backdrops in a documentary photo along with whatever "props" are there to provide context (vases, plates, etc).

 

The potential problem with fluorescing background material is that it might reflect onto parts of your subject which are not fluorescent. So there seems to be no particularly good answer to what to use as background material. I still like the foam paper stuff. I'll try to find a recent use of that in UVIVF and show you.

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Mark, back when I made various UV/IR fotos of Santa, I had also included a UVIVF attempt in the shoot. But I fluffed the focus, so never posted it. I'll show you it here anyway because I was using the white foam paper as a background This stuff does seem to be semi-useful as a background for fluorescent work. You will get some shadows and the idea of a floor underneath your subject. Eventually this paper will get linty.

 

As you can see the white paper version does have a soft blue blue-cyan glow (you were looking for intentional bkg fluor). Again, though, I worry about whether that background glow might affect the fluorescence of what we are trying to photograph. I'm going to see if I have any use of grey foam paper.

 

Everything is wrong with this photo! But at least Santa is not floating in space. "-)

Looks like I aimed the torch from slightly above the figurine and got lumpy elbow shadows.

This is a raw composite, not white balanced.

santaUS_uvi365led_visFluor_20171209wf_8495_rawComp01pn.jpg

 

Here is how the white balance works out for the visible white background which fluoresces blue blue-cyan. On the reference strip, compare the bkg to the blue patch. The fluorescence from the figurine is not super-strong -- somewhere between Medium & Low on the ref strip.

(Gotta please ignore the dust bunnies on sensor pls.)

santaUS_uvi365led_visFluor_20171209wf_8499pn3.jpg

 

Here are the separate channels of the raw composite.

Red

santaUS_uvi365led_visFluor_20171209wf_8495_red.jpg

Green

santaUS_uvi365led_visFluor_20171209wf_8495_green.jpg

Blue

santaUS_uvi365led_visFluor_20171209wf_8495_blue.jpg

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