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Penstemon digitalis [Foxglove Beardtongue]


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#1 msubees

    Zach Huang

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Posted 12 June 2014 - 22:35

Huang, Z.Y. (2014) Penstemon digitalis Nutt. ex Sims (Plantaginaceae) Foxglove Beardtongue. Flowers photographed in ultraviolet and visible light. http://www.ultraviol...ve-beardtongue/

Okemos, Michigan, USA
10 June, 2014
Cultivar in home garden

Other Common Names:

talus slope penstemon

Comment:
Photographs taken at 6pm indoors with with natural light or a portable ultraviolet light, for visible and ultraviolet photograph respectively. The outer part of the corolla is highly reflective for ultraviolet light but the inside becomes totally dark with a false color indigo tint at the transition. Unopened flowers are very UV absorptive, rendering them to nearly completely dark. The anthers, while dark under visible light, become "white" under UV. Thus the flower has a dark corolla with white anther under UV but the opposite for visible light.

Reference:
https://plants.usda....ile?symbol=PEDI

Equipment
Camera: Panasonic Lumix DMC-G5-broadband + El Nikkor 80mm f/4.5].
UV light: Model UVGL-55 Minerallight Lamp, Multiband UV 254/365nm, 115V, 0.16 A, Upland, CA 91786.

Visible Light [f/8 for 0.8" @ISO160, S8612 (1.75 mm thick), indoor natural light]
Attached Image: P1090980-penstemon-VIS.jpg


Ultraviolet Light [f/8 for 20" @ISO160, S8612 (1.75 mm thick) and UG 11 (1 mm thick), indoor, illuminated by a portable ultraviolet light]
Attached Image: Penstemon-UV.jpg

Edited by msubees, 12 June 2014 - 22:46.


#2 msubees

    Zach Huang

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Posted 12 June 2014 - 22:36

I used Photo Ninja to do the WB and this time it was better. However, I had to copy the screen into Photoshop because even after saving in DNG, Photoshop CS3 still failed to render it correctly.

#3 Andrea B.

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Posted 12 June 2014 - 22:46

Did you assign a colour profile during the save from Photo Ninja?
And what default colour profile are you using as a working colour profile in CS3?
Finally what colour profile did you embed when saving for the web from CS3?

Asking because it kinda sounds like there might have been some clash of colour profiles??
Andrea G. Blum
Often found hanging out with flowers & bees.

#4 msubees

    Zach Huang

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Posted 12 June 2014 - 22:57

I only know the saved jpeg has sRGB IEC61966-2.1...I do not know the answers to the first 2 questions...only beginning testing Photo Ninja (did not set and it did not ask) and forgot my default in CS3 (how do I check?).

#5 DaveO

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Posted 12 June 2014 - 23:58

The way I work with Photoninja is to open the RAW (DNG) file and do a white balance against Spectralon/Teflon with my SB-14 flash as light source (for the UV shots only) then render and save the file as a Tiff. I can then open the Tiff in CS5, or any other image editor, to do simple things like a levels luminosity balance. I can assign whatever profile I wish to the file if I don't wish to continue with Adobe RGB which I use as I'm more interested in prints than screen output.

Dave

#6 msubees

    Zach Huang

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Posted 13 June 2014 - 14:52

Dave,
Do you use WB preset? or is it done in Photoninja? Is there a way to do the WB on your "standard" and save it as profile and apply that profile to many other files? Thanks.

#7 msubees

    Zach Huang

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Posted 13 June 2014 - 17:02

"The anthers, while dark under visible light, become "white" under UV. Thus the flower has a dark corolla with white anther under UV but the opposite for visible light." -- does this cancel each out somewhat? of course UV is much weaker compared to VIS. about 10 EV less... not sure if insects perceive that the same as our digital cameras...

#8 JCDowdy

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Posted 13 June 2014 - 17:54

Zach,
You can do an in-camera WB on the Lumix DMC-G5 on PTFE or Spectralon for UV.

#9 msubees

    Zach Huang

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Posted 13 June 2014 - 21:50

John,

Yes, I did that. but I used a regular teflon which seems to be different from the virgin teflon (I just got one), so now I have to use software to adjust all those photos already shot.
.

View PostJCDowdy, on 13 June 2014 - 17:54, said:

Zach,
You can do an in-camera WB on the Lumix DMC-G5 on PTFE or Spectralon for UV.

Edited by msubees, 13 June 2014 - 22:11.


#10 DaveO

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Posted 14 June 2014 - 00:31

Zach,

Just about all my UV shots are taken with a modified SB-14 flash. So I take a shot of the Spectralon/PTFE WB target (at a few different flash to subject distances so I get one shot that isn't blown out. If your WB target shot is over exposed go back to start and do it again to get one that is not over exposed. In CS3 or any other editing program the luminosity values of the target MUST be less that R 255, B 255, G 255. Usually it will only be the red channel that blows out) Then I open that shot in Photoninja and in the Color correction tab I put the eye dropper onto the Spectralon and click accept at which point the images should show a neutral white for the Spectralon. Then go into Preset and save what you have just done to get the WB by just ticking the white balance box and save it as something that makes sense to you. You can also render and save the image as a tiff, then I always close the raw file without saving any changes so I can go back and do everything again if I need to.

Now, with any UV shot taken under exactly the same lighting conditions you can open in Photoninja, click Preset and call up your WB preset, apply and you will get the same result as if you had included the WB target in the same shot and did a WB click on the target.

It's harder to write than to do.

Dave

#11 msubees

    Zach Huang

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Posted 15 June 2014 - 02:25

Dave,

thank you. I am tempted now to buy a copy of the PhotoNinja. can you do "batch processing" with multiple photos with a single preset?

#12 DaveO

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Posted 15 June 2014 - 03:13

Zach,

Yes, there is a "batch render" option. Go to the PictureCode website for PhotoNinja and you will see a whole page of tutorials that should answer all your queries.

Dave

#13 Andrea B.

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Posted 15 June 2014 - 14:00

In addition to reading the PictureCode tutorials, there is a question mark on each page of the app - bottom left I think. Click that for a brief reminder about how the sliders work. Be sure to learn to use the Detail slider (between 8-15) as it adds interesting depth and local contrast.

You can save frequently used basic edits and white balances as Presets in PN. I find this immensely valuable and time-saving. I haven't batched much in PN because I tend to select the best photo for converting and ignore the rest. "-) Good to know from Dave that it works.

Photo Ninja can only do global edits, but many times that is all that is needed for a well-shot UV photo. But you have CS3 for masking and local edits. PN is pricey, but many of us think it is worth every penny for its excellent conversions and white balancing capability.

With PN you get free updates for a year. But you really only need to update if you get a new camera not covered by an old version of PN or if they add some new tool which you might want to use.
Andrea G. Blum
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#14 msubees

    Zach Huang

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Posted 19 June 2014 - 18:24

Andrea,

Thanks for the info! I will try to learn it...With 50% off, it is not so bad. I paid more for Lighroom not long again and it is not very useful for UV stuff.