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Fluorescence time-lapse - sort of!

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#1 Adrian

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Posted 01 December 2017 - 11:47

Hi,
I have been wanting to show how fluorescence in plants changes over a period of time. I today photographed three pitchers of the carnivorous pitcher plant: Nepenthes x Hookeriana (a lowland hybrid).

From left, the image shows an unopened pitcher, a nearly open pitcher, and a full open pitcher (all on the same plant). I assume there is no point in the pitcher fluorescing until it is ready to attract and capture prey. Interesting change in the overall colour of the pitcher too! The peristome (upper ring) of the pitcher does not fluoresce as brightly in this species as it does with some others I have photographed. I think it would be worth doing similar exercises with berries (e.g. Ivy) which attract birds, and which change colour over a period of time.

Technical details: Nikon D800 with 105mm micro-Nikkor lens. Visible 1/160th @f/16. UVF: Convoy S2+ LED UV source. approx 10 seconds @f/16, constantly painting the subjecty during the exposure.

Attached Images

  • Attached Image: Nep comp visible web.jpg
  • Attached Image: Nep comp UVF web.jpg


#2 Cadmium

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Posted 01 December 2017 - 16:10

Adrian, Very nice !

#3 Hornblende

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Posted 01 December 2017 - 16:10

Oh this is so cool!
I have three Nepenthes at home, I have to try this!

#4 Andy Perrin

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Posted 01 December 2017 - 17:22

Lovely photos! Very interesting.

#5 Andrea B.

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Posted 01 December 2017 - 17:45

Excellent work, Adrian. What a fascinating plant! Thank you for posting this.

I'm wondering how you handle the white balance in your visible fluorescence photos?
Andrea G. Blum
Often found hanging out with flowers & bees.

#6 Mark

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Posted 02 December 2017 - 14:35

Very interesting indeed. I also question the white balance across the photos. Perhaps including a control target in each image would help to allow for comparison/contrast.

#7 Adrian

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Posted 04 December 2017 - 09:31

Andrea, Mark,
Thanks for your comments! I must admit I have been rather lazy with "white balancing" my UVF images. I generally use either the MTE303, or Convoy S2+ LED UV sources, and do the metal test do ensure there is minimal visible light being emitted.

I have looked at the UVF sticky, but there does not seem to be a consensus with regard to an affordable target. I have investigated targets such as the AIC PhotoDocumentation chart, but they are all well outside my budget. Do you have any thoughts as to a standard control target to use in UVF?

In the case of the above image, all three UVF images were shot at the same exposure (within one or two seconds) and same light source, so I am confident the colour change is due to the maturity of the plant.
Thanks

#8 Andrea B.

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Posted 05 December 2017 - 04:25

The only manufactured targets for UV-Induced Visible Fluorescence which I currently know about are mentioned in the UVIVF Sticky. Those are the UV Innovations UV-GreyTM for white balance and the Target-UVTM used to judge the strength of the fluorescence. The Target-UV has white/grey patches which can be used for WB too.

Some of us have been on the lookout for some paint which fluoresces white under UV. I have one on order and will certainly let everyone know if it proves to be useful for fluor photography.
Andrea G. Blum
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#9 Shane

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Posted 07 December 2017 - 16:46

Lab sphere used to make fluorescence standards....not sure if they still do.

#10 Andrea B.

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Posted 08 December 2017 - 06:00

Yes, Labsphere does make some color fluorescence standards. And they also make some standards for judging paper fluorescence. But I was under the impression that the latter were blue or what is called blue-white. However, it has been some time since I looked at those and I might be wrong about that! I do not recall seeing a grey fluorescent standard on the Labsphere site.
Andrea G. Blum
Often found hanging out with flowers & bees.