Old UV photos with gradient remapping

[Andy Perrin]

These photos were all taken with my Coolpix 995 and the Omega 330WB70 filter.

 

Since I have never found a consistent way to adjust for the large focal shift, and I cannot see what I'm doing when I take the UV photos, my procedure is to manually increase the focal distance in increments of 2 cm or so and take about 10 photos, then choose the most in-focus one after I get back to the computer. I never know what will happen! Often I repeat the process at different ISO or exposure times also, in hopes of maximizing my chances. I haven't been recording exposure, F-number, etc., so I can't tell you what they are.

 

As they come out of the camera, my photos generally have a blue and a red channel of roughly the same intensity, but nothing in the green, ever. Since I was getting essentially monochrome results anyway, I started using Photoshop to remap the intensities to false colors chosen for beauty. So these are TRULY false color images, not like the pseudo-colors I most often see on this forum, which seem to have SOME relationship to UV wavelength.

 

All species names are my best guess. Clever botanists should feel free to offer corrections and I will edit the post if need be.

 

Symphoricarpos albus (visible)

Symphoricarpos albus (UV)

 

Silene latifolia (visible)

Silene latifolia (UV)

 

Saponaria officinalis (visible)

Saponaria officinalis (UV, one of two color schemes for same photo)

Saponaria officinalis (UV, second of two color schemes for same photo)

 

Hemerocallis Fulva (visible)

Hemerocallis Fulva (UV, with colors chosen to mimic the visible photo)

 

I have nicknamed this one Audrey 2 for reasons that will be clear to those fond of musicals.

 

Asclepias syriaca (visible)

Asclepias syriaca (UV)

[nfoto]

Andy, the botany seems to be all right as far as identification goes. That being said, I'm much more uncertain about the UV content of these images. Perhaps you have succeeded to record just a little into the upper UV-A? Hard to tell when the sampled species are not amongst those with a familiar UV appearance. The Hemerocallis in particular suggests there are some UV features present.

[Andrea B.]

I think that these images show the correct UV. We have posted Silenes and they are moderately UV absorbing like this one with some shimmer from conical cells. I have a Saponaria (unposted) which looks like this one. Ditto the Aesclepias. The H. fulva is correct and this version shows the dark patches very well.

 

I don't know the berries. But isn't that a nice texture revealed by the UV?

 

Pretty cool that the pix from the little Coolpix are this good. We've hardly ever see UV photos from converted point-n-shoots. There are of course dynamic range issues and easy blowouts from these early digicams, but still, not bad.

[Andy Perrin]

For something more conventional (to gauge the UV response) this black-eyed susan might be better? The UV pic is basically as it came from the camera but with blue channel copied into the green, and some sharpening.

 

[nfoto]

That Rudbeckia is a better evidence of having recorded a UV signature indeed.