Infrared fluorescence of banana cross rection (850nm+, 365nm LED)

[Fandyus]

The fluorescence was very weak. I had to use ISO 800 with a 30s exposure to achieve this photo. I also had a relatively strong UV LED chip's entire output focused directly onto the banana (using the built in "zoom" feature of the torch).

[Andy Perrin]

That’s pretty typical for UV-induced IR fluorescence I think? Using 720+nm filter would have let you lower the ISO a bit maybe. 
 

Photo is neat!

 

Possibly using green light as the stimulus might be interesting. 

[Fandyus]

Just now, Andy Perrin said:

That’s pretty typical for IR fluorescence I think? Using 720+ would have let you lower the ISO a bit maybe. 

Perhaps, but I like the idea that this is exclusively what we can't see. Also, when the picture is entirely monochrome, I can bypass demosaicing, which is a bonus. Makes the noise characteristics similar to the Leica Monochrom.

[Andy Perrin]

If you have a mac, that program Lukas uses, Accuraw Monochrome, lets you recover extra detail from 850+nm pics. 

[lukaszgryglicki]

Yep this program is OK, but sometimes crashes.

 

[Foxfire]

Interesting! I may be wrong but believe that the fluorescence peak for these brighter fibrous things (cellulose?) is in visible, dropping off in NIR. So it looks like the banana needed a good amount of UV for UViIRF. One of the brightest glowers i've found are some paints used on pottery. Something called cadmium red should be one. 

[Fandyus]

2 hours ago, Andy Perrin said:

If you have a mac, that program Lukas uses, Accuraw Monochrome, lets you recover extra detail from 850+nm pics. 

Thank you, I don't have a mac though. I use darktable's passthrough "demosaicing" option which really just displays each photocell as it is without assigning color.

[Fandyus]

4 hours ago, Andy Perrin said:

That’s pretty typical for UV-induced IR fluorescence I think? Using 720+nm filter would have let you lower the ISO a bit maybe. 
 

Photo is neat!

 

Possibly using green light as the stimulus might be interesting. 

I see you have edited your comment.

Thanks for the compliment.

Green would be interesting but the best source of green light I have as of now is not very concentrated so I imagine it would not exactly make the banana glow a lot, I don't have a remote control for my Sony a6000 and for some godforsaken reason they couldn't just program in some function that would make the camera expose for longer than 30s on its own, so that would be a problem also.

[Andy Perrin]

1 hour ago, Fandyus said:

I see you have edited your comment.

You just replied to my comment before I was quite done editing it earlier, and then you didn't notice the additions until now...

 

Remotes from 3rd parties are available very cheaply online (I think I paid $10?). I had the same problem with my Sonys. Fortunately it's not a hard fix.

[Lou Jost]

Deep blue is a strong exciter of chlorophyll. I'm not sure if green is. But UV is better. 

[Nate]

Photo looks great, and thanks for the tip about darktable.

 I tried it, but after selecting passthrough, I needed to wb a spot then turn off color calibration, then put wb back to camera. Strange, but the outcome is better than not doing it.

[Unscenerie]

Very intriguing photo. Reminds me of how a sonograph picture looks.

[Fandyus]

17 hours ago, Andy Perrin said:

You just replied to my comment before I was quite done editing it earlier, and then you didn't notice the additions until now...

 

Remotes from 3rd parties are available very cheaply online (I think I paid $10?). I had the same problem with my Sonys. Fortunately it's not a hard fix.

Thanks, yeah I checked. I also tried (and failed) to connect the camera to my phone to see if I could use that instead.

[Fandyus]

16 hours ago, Lou Jost said:

Deep blue is a strong exciter of chlorophyll. I'm not sure if green is. But UV is better. 

Oddly enough, green also makes leaves fluoresce. Although I have only tried it on a yellowed leaf, so that probably did not have much chlorophyll left.

[Fandyus]

15 hours ago, Nate said:

Photo looks great, and thanks for the tip about darktable.

 I tried it, but after selecting passthrough, I needed to wb a spot then turn off color calibration, then put wb back to camera. Strange, but the outcome is better than not doing it.

Glad it helped. I usually just color balance the photo and then set the demosaicing to passthrough. But I do use a custom preset prior where I turned off as many modules as possible to get the data represented objectively.

6 hours ago, Unscenerie said:

Very intriguing photo. Reminds me of how a sonograph picture looks.

Thanks.

[microbat52]

Oooh really cool! I love how UVIIR always looks so ghostly.