Tradescantia occidentalis [Prairie Spiderwort]

[dancingcat]

Frary, S.C. (2023) Tradescantia occidentalis (Britton) Smyth (Commelinaceae) Prairie Spiderwort. Photographed in visible and ultraviolet light.

Collected 12 April 2023 in an open field near Richland-Chambers Lake, Eureka/Corsicana, Navarro County. Texas, USA. Voucher deposition: Botanical Research Institute of Texas Herbarium (BRIT), Fort Worth Botanic Garden, S. C. Frary [166].

Other Common Names:  Western Spiderwort 

Comment: Growing in very large patches of Indian Paintbrushes (Castilleja spp., both orange and yellow flowers); also with Texas Bluebonnet (Lupinus texensis), Pink Lady (Oenothera speciosa), and Cutleaf Evening Primrose (Oenothera lacianata).  Common in limestone soil.  Spiderworts are notorious hybridizers and difficult sometimes to differentiate, so this may need an edited determination at some point. 

Reference: Lady Bird Johnson Wildflower Database, University of Texas at Austin.

Equipment: [Olympus EM1mk2-broadband + Olympus 90mm 1:3.5 macro lens.  Filters: Visible - KolariVision hot mirror 2, UV - Baader U.  In situ photograph was taken with an iPhone.  Ultraviolet source: Convoy S2 flashlight.  Visible and UV photographs are 15 images each, processed in Helicon Focus. Exposures ISO 200, f/11, 6 sec for UV, 4 sec for visible.] 

The Helicon stacks have various technical problems, some caused by flower movement during the exposure, and some caused by inconsistent lighting.  I should have used a static UV source with this flower instead of a flashlight "paint".  This flower only lasts a day, and I suspect this one was at the end of its life and starting to wilt while I was working with it.  This is an in-camera set of images, so that may have contributed to the blur also.  Olympus usually does a good job with that, but sometimes not.

[Andy Perrin]

I think some flowers react in realtime to UV also. Flowers are very much more active organisms than people usually think, aren’t they!

[photoni]

@dancingcat  don't be offended... your images are too big, my pc gets slow to load them.
my personal taste... it seems to me that the iPhone photo has more real colors than the one with the "KolariVision hot mirror 2" this one is alien, too saturated.
Then the photo with "Baader U" looks like a black and white photo tinged with purple, a neutral part is missing, how did you do the white balance?
HI
Toni

[Andrea B.]

Dancing Cat, yes indeedy, as you have observed flowers do sometimes move while we are trying to get that UV photo. Aside from the obvious movements due to breezes or wilting, I've had more than one which moved in response to the UV light. And I've had a couple which moved because they were heliotropic, following the sun. I would suggest making an additional single-shot, unstacked UV photo along with your stacked versions so that you provide the Herbarium with at least one stable version?

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We do not have a size restriction on images here, but as a courtesy it is best to downsize them. Nobody can ever see images in a browser at the full size of 4792 x 3730 pixels. And it does take longer to load big images. Resizing is a good skill to learn. Try for a maximum of 1200-2000 pixels. (Sometimes images must be resharpened after downsizing.)

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Toni, Tradescantia *is* an intensely colored flower. The iPhone version is a little bit undersaturated. But you raise a good issue:  how do we get the proper color saturation in a documentary photo? I'm not entirely sure of the answer to that. I've profiled the color of my cameras, but that does not entirely solve the problem. 

Link to another Tradescantia-like flower:  Commelina communis [Asiatic Dayflower]

 

[photoni]

7 hours ago, Andrea B. said:

I've profiled the color of my cameras

 

I think profiling a camera with a fixed aperture lens, with just that stack of filters with just that light at that time of day...is like a unicorn.

Nothing good and stable has ever come out to me.

 

white balance has standard parameters ...
even if it is a simplistic convention
since the Bayer filter is not made for UV or IR.