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Citrus unshiu [Satsuma Tangerine]


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#1 Andrea B.

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Posted 30 December 2014 - 06:41

Blum, A. (2014) Citrus unshiu (Swingle) Marcow. (Rutaceae) Satsuma Tangerine. Fruit photographed in Visible and Ultraviolet light. UV-Induced Visible Fluorescence also included. http://www.ultraviol...suma-tangerine/

Synonyms:
  • Wenzhou migan (Chinese: 温州蜜柑)
  • Unshu mikan (Japanese)
  • Naartjie (Afrikaans)
  • Satsuma Mandarin
Comment:
This tangerine was purchased at a Whole Foods grocery. But I don't think it was an "organic" version because there appears to be some fluorescent residue from wax or sprays or something. References mention that the skin has many large prominent oil glands which might also be the cause of some of the fluorescent phenomena seen below.

Note: The visible colour in the fluorescence photographs below was adjusted in the editor to match what was seen during the shoot, but the colour may not be entirely accurate.

Reference:
1. Wikipedia (30 Dec 2014) Citrus unshui. Wikimedia Foundation, San Francisco, CA.
2. Andersen, Ferguson & Spann (Oct 2012) The Satsuma Mandarin. Publication #HS195, Horticultural Sciences Department, Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida, Gainesville, FL.

Equipment: D600-broadband + Zeiss 60mm f/4 UV-Planar

Visible [Baader UVIR-Cut Filter + Visible LED Flashlight]
f/11 for 3" @ ISO-100 in Darkness
This tangerine is so pretty and interestingly textured.
Attached Image: satsumaTangerine_VisLed_BaaderUVIRCut_20141229wf_28841pnPf1.jpg


UV-Induced Visible Fluorescence [Baader UVIR-Cut Filter + Nichia 365nm UV-LED Flashlight]
f/11 for 3" @ ISO-400 in Darkness
The white balance is slightly too blue, but this was the best I could do this time.
Attached Image: satsumaTangerineFluor_Filtered365UVLed_BaaderUVIRCut_PRESET3_20141229wf_28847pnPf1.jpg


Ultraviolet [Baader-U + Nichia 365nm UV-LED Flashlight]
f/11 for 3" @ ISO-400 in Darkness
The tangerine is really UV-dark, but the skin is "shiny" so it's not easy to see that unless you compare several shots made with different lighting angles. We really need to experiment with a UV-polarizer someday.
Attached Image: satsumaTangerineUV_Filtered365UVLed_BaaderU_PRESET2_20141229wf_28906pnPf1.jpg


UV-Induced Visible Fluorescence [Baader UVIR-Cut Filter + Nichia 365nm UV-LED Flashlight]
f/11 for 2.5" @ ISO-500 in Darkness
Close-up. That's the stem to the right. I don't know what the yellow patch is - dried tangerine juice perhaps?
Attached Image: satsumaTangerineFluor_Filtered365UVLed_BaaderUVIRCut_PRESET3_20141229wf_28928pnPf.jpg


UV-Induced Visible Fluorescence [Baader UVIR-Cut Filter + Nichia 365nm UV-LED Flashlight]
f/11 for 2.5" @ ISO-500 in Darkness
Close-up. None of the fluor patches looks at all like mold.
Attached Image: satsumaTangerineFluor_Filtered365UVLed_BaaderUVIRCut_PRESET3_20141229wf_28998pnPf.jpg
Andrea G. Blum
Often found hanging out with flowers & bees.

#2 colinbm

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Posted 30 December 2014 - 07:16

All nicely done Andrea
Col

#3 Andrea B.

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Posted 30 December 2014 - 15:12

Thanks, Col.

I like "painting with light" in the darkness.

I am having second thoughts about eating these Tangerines. It might be a good idea never to shine UV upon ones food choices to see what actually lurks there. Of course, the stuff is only on the unedible peel. "-)
Andrea G. Blum
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#4 Damon

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Posted 30 December 2014 - 15:40

Wow that is fantastic! Nice and sharp and the colors are very interesting.
Man that lens sure focuses close. Did you use any extension tubes?

The closer you get the freakier some of these things look.

Re: second thoughts--I thought about doing another post titled "What not to do with your UV light" and do all kinds of food and the stove top etc. It would be fun, informative and disgusting at the same time.

Nice work. I have some clementines that I can try out. Did you wash your's first or no?

-D

#5 Adrian

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Posted 30 December 2014 - 15:52

I have also been photographing citrus fruit mould, in this case, a Satsuma, in UV fluorescence. Here, the fruit was visibly mouldy, though not as much as the UV showed!
Adrian Davies

Attached Images

  • Attached Image: satsuma 1.jpg
  • Attached Image: satsuma UV 1.jpg

Adrian Davies
www.imagingtheinvisible.com

#6 colinbm

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Posted 31 December 2014 - 02:55

Nice work Adrian
It sure shows where the mold is going to breakout next though.
Col

#7 Damon

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Posted 31 December 2014 - 03:58

Very interesting Adrian.
That's some serious eye-popping yellow!
Thanks for posting it.

What was your lighting source regarding the fluorescence shot?

-Damon

#8 Adrian

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Posted 05 January 2015 - 16:07

I use two old (40 years?) PW Allen A409 light sources (condemned about 10 years ago from the bio lab in the college where I used to work because they failed a UK PAT test). I have been using them fairly constantly ever since.
Adrian Davies
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#9 Andrea B.

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Posted 05 January 2015 - 16:19

That is some lovely blue-green mold, Adrian. Thanks for posting this fluorescence example.
Andrea G. Blum
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#10 Andrea B.

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Posted 06 January 2015 - 17:10

Man that lens sure focuses close. Did you use any extension tubes?

The UV-Planar, which is basically a specialized enlarger lens, has no built-in focusing helicoid and must be used with an add-on helicoid. Helis can be found in various extensions and lens/mount configurations on Ebay. I have threee - approximately 12-17mm, 17-30mm and 30-50mm.
Andrea G. Blum
Often found hanging out with flowers & bees.