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Front vs Back lighting

Multispectral
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#1 Mark

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Posted 13 March 2018 - 18:44

This is one of the tomatoes from my recent post (http://www.ultraviol...ing-technology/), but I've started a new thread here in consideration of front- versus back-lighting technique. I'm not exactly sure how I feel about back-lighting just yet; I need to mull over these results for a while before I make my decision.

I started out by simply cutting the tomato in half, and shooting a quick, back-lit IR image to see what I was up against.
Attached Image: 2018-03-11_19-01-07_940led_r72.jpg

Obviously there wasn't much of anything interesting going on, so I cut it down to a slice about 10 mm thick. Now things got a bit more interesting, with the back-lit image having a mild 'x-ray' like effect, and the front-lit image showing strong transparency in the flesh (especially as compare to the UV image).
Attached Image: ir_back-v-front.jpg

Here's the VIS comparison. Color and texture appears washed out in red saturation in the back-lit version.
Attached Image: vis_back-v-front.jpg

I definitely have mixed feelings about the UVIVF results. The back-lit image has striking colors, but I believe much of this is just secondary VIS illumination from whatever fluorescence is being generated on the other side. While the front-lit image looks much less colorful, the fine structures are evident here (more so in the full size original image).
Attached Image: uvivf_back-v-front.jpg

I did not shoot a front-lit UVIIF image. I have no idea why. Old age / simply forgot? Either way, here's the back-lit UVIIF image; which I like even though I don't see that it offers much of anything special (aside from color).
Attached Image: 2018-03-11_19-12-06_mte_r72.jpg

I did shoot a UV back-lit image :). But it was completely black (no surprise actually), so I'm not going to bother to post its photo of basically nothing. Here is the front-lit version though, showing the dense, fine structures in the flesh.
Attached Image: 2018-03-11_19-18-46_s2_0340.jpg

Hardware (all images): Lens: 50 mm Nikon series E, Body: Nikon D750 N1404 [broadband]

#2 bobfriedman

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Posted 13 March 2018 - 19:18

interesting post Mark!

#3 Cadmium

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Posted 15 March 2018 - 00:31

Mark, Very interesting examples.

#4 Andrea B.

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Posted 19 March 2018 - 22:02

It is a study in how a tomato filters light.

I do like the artistic possibilities in this. Although the outcomes seem to have less to do with light type than with the fact of the backlighting. That translucent tomato gel stuff (nice botanical term there, eh?) provides a brighter background for a dramatic dark seed outline.


The UVIVF backlit image looks Halloween-ish. Scarey tomato pumpkin thing. Cool.
Andrea G. Blum
Often found hanging out with flowers & bees.

#5 Andy Perrin

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Posted 20 March 2018 - 00:37

The tomato filter. That's a new idea! Don't worry, I won't tell Baader. :D