Search the Community

One of the things I have been trying for some time is to get interesting UV photos of flowers in Stereo (i.e. 3D), especially in close-up and macro. In this post I'll outline the technique (happy to provide more detail if you need it), and provide some samples: you will need red/cyan anaglyph glasses (a couple of $ on ebay or Amazon) to view them. Also because of the 800 pixel-width that UVP impose, you will not get the full effect, and won't be able to do what I love - zooming in and "wandering around" the flower and looking at the detailed internal structure. If you've got some red/cyan glasses and want to look at some full-resolution files then drop me a line. And if you haven't got the glasses but would like to see any of the detailed images in 2D, let me know - but you really lose a lot in 2D. I've now got to a point where I get a reasonable percentage of successes, although some flowers make life difficult because of the amount they move during the process: some move in their entirety (wilting, esp. under the bombardment from flashguns), and some just waggle their stamens about. Dandelions are particularly irritating in this respect. This movement is a problem because it can easily take 30-45 minutes to complete one stereo shot. This is because I use focus stacking to get the image quality and depth of field, and that can mean 100 shots for each of the stereo pair of images. The traditional way to make stereo pairs is to move the camera sideways between the two images. For image distances of 1-10 metres, the sideways separation would be the inter-ocular distance of 6 or 7 cms; for greater image distances you would use greater separations (I have used 100 metres for a subject 12 miles away), and for shorter distances a smaller separation. However, for macro this does not work - with even a small separation the image disappears from the field of view. So you need to use a toe-in approach - swing the camera through about 5 degrees between the two stereo images, and then move it sideways until the image comes back into the field of view. There is nothing magical about 5 degrees - it is the angle between the line of sight of the 2 eyes for a subject at 0.5 metres. Other people use 3.7 degrees, or some other number. If you read materials about stereo photography, they often say that toe-in is a definite non-no, but modern 3D software can handle it perfectly. (I use the excellent and free Stereo Photo Maker to create the stereo image from my stereo pairs.) One of the difficulties with any kind of macro work is the shallow depth of field that you experience. To overcome this I use focus stacking - taking a number of mages focused on different planes in the subject, and combining them in software to get a single sharp image. I use Zerene software for this. This also overcomes the problem of how to focus accurately in UV, because all you need to find out is where the image starts to come into focus and where it starts to go out of focus. Another difficulty with UV+macro is getting enough light on the subject. I use 3 cheap-from-China but powerful WS-560 flashguns (with UV-absorbing "lens" removed) a few centimetres away from the subject. The repeated shooting for focus-stacking overheats the flashguns, and already three have failed for this reason. But they're so cheap (I just bought a couple new for $20 each) that they're effectively a consumable rather than a capital purchase. Let's look at some examples. They're all taken on a full-spectrum Canon EOS M, U340+S8612 filters, flash, white-balanced on PTFE. Lenses were either a Steinheil Cassar S 2.8/50mm and El-Nikkor 5.6/105mm, always stopped down to f/8. First, one that didn't work so well. This is a type of Geranium AFAIK. The body of the flower is OK, but the central area is not so good to look at. This is because of stamen movement. I mentioned above that Dandelions cause movement problems. This shot isn't too bad, but I had to crop it a lot to get rid of moving petals. Fruit blossom seems to work well - here is Quince, Pear, Alpine Strawberry. On the strawberry, you'll see a couple of tiny spiders in cyan. This is an irritant that comes from focus stacking - insects that wander around the flower while you are taking the images. In fact on this shot there were about a dozen out-of-focus spiders in cyan (i.e. on the right image) and a few in red (i.e. on the left image) which I had to post-process out of the image. Now we have a Daffodil. This works really well in a full-resolution image, with the a great wander-about capability. Here are a few shots of an Orchid - full flower and then a macro shot of the interior. I have provided a visible light shot (taken on a Canon EOS 6D Mk 2, Sigma 105mm macro lens, ring flash) of the interior for comparison. The UV interior shot is another great one to wander around. Now a Bluebell: A chrysanthemum: A daisy: A Grape Hyacinth: An "ordinary" Hyacinth: Magnolia (this is another flower that can move significantly when young - I could actually observe it twitching): Snowdrop (also good for wandering around inside): Forsythia: And finally a Sunflower:

Wilhelmson, U. (2020) Myosotis L. sp. (Boraginaceae) Forget-me-not. Stacked photo in reflected ultraviolet light. https://www.ultravio...-a-tiny-flower/ Reference: 1. Wikipedia (08 Dec 2020) Myosotis. Wikimedia Foundation, San Francisco, CA. Comment: For my my first test stack trying my Milar 6.5cm/4.5 I used a very small ForgetMeNot that has been kept reasonably fresh in my fridge for several weeks. The flowers are very tiny, only a bit more than 1mm in diameter. The stack is made from 24 images with a UV-pass filter stack: S8612, 2mm + U-360, 2mm. The magnification is 2.4x on the sensor. A closer crop with no additional sharpening.

Foot, Bernard (2020) Centranthus ruber L. (Caprifoliaceae) Red Valerian. Flower photographed in visible and reflected UV light together with UV Stereo Anaglyph. https://www.ultravio...an-uv-anaglyph/ Location: Date: 16 May 2019 Reference: 1. Wikipedia (29 June 2021) Centranthus ruber. Wikimedia Foundation, San Francisco, CA. 2. Fitter, R., Fitter, A. and Blamey, M. (1996) Wild Flowers of Britain and Northern Europe, 5th Ed. Red Valerian, page 234. HarperCollins Publishers, London, U.K. Visible Light Ultraviolet Light (Baader U, flash): UV Stereo Anaglyph

Blum, A.G. 2017. Houstonia caerulea L. (Rubiaceae). Quaker Ladies. Flowers photographed in ultraviolet, visible and infrared light. http://www.ultraviol...-quaker-ladies/ Updated 24 Oct 2017: Set #3 added to post #2. Updated 27 May 2018: Restructured common names. Synonyms: Hedyotis caerulea (L.) Hook. Houstonia caerulea var. faxinorum Pease & Moore Other Common Names: Bluets Comment: The UV-black heart of the innocent little Quaker Lady is revealed! The visible colour of this tiny flower varies from a very pale blue which is almost white to a slightly more saturated sky blue. The central structures of the flower are nicely brought out in UV. Reference: 1. Mittelhauser et al. (2010) Bluets, page 334. The Plants of Acadia National Park. The U. of Maine Press, Orono, ME. 2. Newcomb, L. (1977) Bluets, page 156. Newcomb's Wildflower Guide. Little, Brown & Co., New York City, NY.
 SET 1 Kinship Lane, Southwest Harbor, Maine, USA 15 July 2012 Wildflower Equipment [Nikon D300-broadband + Carl Zeiss 60mm f/4.0 UV-Planar] Visible Light [f/11 for 1/60" @ ISO 200 with onboard Flash and Baader UVIR-Block Filter] Ultraviolet Light [f/11 for 1/60" @ ISO 200 with SB-14 UV-modified Flash and Baader UV-Pass Filter] Ultraviolet Light: This 100% crop from the preceding photograph shows the conical cells.

An interesting variety of the flower-bee interaction recently has come to light, see for example http://www.npr.org/2...arge-on-flowers I wonder whether our old enigmatic friends, the conical cells, have a role in such phenomena?

Blum, A.G. (2015) Another Example of Tripleurospermum maritimum (L.) W.D.J. Koch (Asteraceae) Sea Mayweed. Flowers photographed in ultraviolet and visible light. http://www.ultraviol...nother-example/ Shore Cottage, Southwest Harbor, Maine, USA 26 July 2014 Wildflower Synonyms: Matricaria maritimum L. Scentless Chamomile Sea Chamomile Comment: I have identified this specimen as being Tripleurospermum maritimum based on its slightly sprawling habit, coastal location and the fact that the leaves remain fleshy to the very tips. There is some disagreement about whether T. maritimum and its very close cousin T. inodorum should be separate species. Rørslett (2012) first showed T. maritimum in ultraviolet(1). This example also also exhibits a UV-absorbing appearance under the BaaderU UV-pass filter. Reference: 1. Rørslett, B. (2012) Tripleurospermum maritimum (L.) W.D. Koch (Asteraceae) Sea Mayweed. Flowers photographed in visible and ultraviolet light. http://www.ultraviol...um-sea-mayweed/ 2. New England Wild Flower Society (2015) Tripleurospermum maritimum (L.) W.D.J. Koch. Scentless Chamomile. https://gobotany.new...rmum/maritimum/ Equipment [Nikon D600-broadband + Carl Zeiss 60mm f/4.0 UV-Planar] Visible Light [f/11 for 1/2.5" @ ISO-400 with onboard Flash and Baader UVIR-Block Filter] This specimen is a bit battered and also hosts some critters. Visible Light [f/11 for 1/1.6" @ ISO-400 with onboard Flash and Baader UVIR-Block Filter] The thread-like leaves remain fleshy until the tip. Ultraviolet Light [f/11 for 2" @ ISO-400 with SB-14 UV-modified Flash and Baader UV-Pass Filter] The rays and disk are UV-absorbing. There is some iridescence on the top surface. Each ray has two slightly darker stripes. Ultraviolet Light [unresized crop from preceding foto] Conical cells. Visible Light [f/11 for 1" @ ISO-400 with onboard Flash and Baader UVIR-Block Filter] An abaxial view of the rays and involucre. Ultraviolet Light [f/11 for 15" @ ISO-400 with SB-14 UV-modified Flash and Baader UV-Pass Filter] A long exposure was taken so that multiple flashes could be used. The abaxial rays show quite a lot of iridescence.

Blum, A.G. (2013) Lilium henryi Baker x speciosum Thunberg 'Black Beauty' (Liliaceae) Orienpet Lily. Flowers photographed in ultraviolet and visible light. http://www.ultraviol...-orienpet-lily/ Middletown, New Jersey, USA 28 July 2013 Cultiver in home garden Comment: Black Beauty is a cross between Henry's Lily, L. henryi, a Trumpet lily and the Japanese Lily, L. speciosum, an Oriental lily - thus becoming an Orienpet lily. The green grooves at the base of the petals produce nectar. This lily is UV-dark, but dense conical cells on the petals produce a strong, bright iridescence where the UV light rakes across them. Reference: 1. Missouri Botanical Gardens (2013) Lilium 'Black Beauty' http://www.missourib...ack-beauty.aspx Equipment [Nikon D600-broadband + Nikon 105mm f/4.5 UV-Nikkor] To best view these 1000-pixel wide photos, please expand your browser. Visible Light [f/16 for 2" @ ISO 100 with onboard Flash and Baader UVIR-Block Filter] The raspberry red, white-edged petals and the green and white central star give Black Beauty a distinctive appearance. Visible Light [f/16 for 2.5" @ ISO 100 with onboard Flash and Baader UVIR-Block Filter] The green grooves at the base of each petal ooze sticky nectar. Visible Light [f/16 for 2.5" @ ISO 100 with onboard Flash and Baader UVIR-Block Filter] Anther. Visible Light [f/16 for 1.3" @ ISO 100 with onboard Flash and Baader UVIR-Block Filter] The graceful retroflexed petals with their green ribs give Black Beauty a pretty back view. Ultraviolet Light [f/11 for 20" @ ISO 400 with SB-14 UV-modified Flash and Baader UV-Pass Filter] The petals are densely covered in conical cells creating a strong iridescence on the UV-dark petals. Ultraviolet Light [f/16 for 15" @ ISO 400 with SB-14 UV-modified Flash and Baader UV-Pass Filter] The petals have an adaxial UV-dark stripe and abaxial UV-dark ribs. Ultraviolet Light [f/16 for 15" @ ISO 400 with SB-14 UV-modified Flash and Baader UV-Pass Filter] A petal close-up showing the dense conical cells. Ultraviolet Light [100% crop from preceding photo]

Oldfield, D. 2013. Eremophila calorhabdos Diels (Scrophulariaceae) Red Rod. Flowers photographed in visible and ultraviolet light. http://www.ultraviol...habdos-red-rod/ Synonym Stenochilus calorhabdos (Diels) Kraenzl. Comment The name of this eremophila is said to mean ‘beautiful wand’. This bird pollinated (ornithophilous) eremophila has a pink corolla which is the typical shape for eremophila pollinated by honeyeaters and other Australian birds with long slender beaks which visit the flowers for their nectar. SET 1 Maldon, Victoria, Australia 25 December 2013 Australian Native Wildflower as Garden Specimen Visible Light: Pentax K-5 Full Spectrum Modification, Nikon Rayfact PF10545 MF-UV 105 mm f/4.5 lens, Metz 15 MS-1 flash, 1/180 s @ f/16 ISO 200, B+W UV/IR Cut Filter. Image Reference: DO51995 Ultraviolet Light: Pentax K-5 Full Spectrum Modification, Nikon Rayfact PF10545 MF-UV 105 mm f/4.5 lens, Nikon SB-14 flash, 1/180s @ f/16 ISO 200, Baader UV-Pass Filter. Image Reference: DO51998 100% closeup extract from UV image The conical cells covering the inner surface of the corolla are clearly visible SET 2 Maldon, Victoria, Australia 1 March 2015 Australian Native Wildflower as Garden Specimen Visible Light: Pentax K-5 Full Spectrum Modification, Nikon Rayfact PF10545 MF-UV 105 mm f/4.5 lens, Metz 15 MS-1 flash, 1/180 s @ f/16 ISO 200, Baader UV/IR Cut Filter. Image Reference: DO54286 Ultraviolet Light: Pentax K-5 Full Spectrum Modification, Nikon Rayfact PF10545 MF-UV 105 mm f/4.5 lens, Nissin Di866 Mark II flash, 1/180s @ f/16 ISO 200, Baader UV-Pass Filter. Image Reference: DO54289 Ultraviolet Induced Visible Fluorescence: Pentax K-5 Full Spectrum Modification, Nikon Rayfact PF10545 MF-UV 105 mm f/4.5 lens with Baader UV/IR Cut Filter, Nichia NCSU033A UV-LED with Baader UV-Pass Filter, 30.0 s @ f/11 ISO 200. Image Reference: DO54294 References: 1. Chinnock, R.J. Eremophila and Allied Genera, Rosenberg, 2007, p. 569. 2. Boschen, N., Goods, M. and Wait, R. Australia’s Eremophilas – changing gardens for a changing climate, Bloomings Books, 2008, p.35. 3. Atlas of Living Australia http://bie.ala.org.a...ila+calorhabdos SET 1: Published 1 January 2014 SET 2: Published 1 March 2015

Blum, A.G. (2015) Saintpaulia sp. H. Wendl. (Gesneriaceae) African Violet. Flowers photographed in ultraviolet and visible light. http://www.ultraviol...et-iridescence/ Comment: The petals of this African violet provide the best examples of conical cell iridescence I've photographed thus far. There is real colour change based on the directionality of the light. So I have posted more than the usual number of examples to illustrate this. Set 1 Middletown, New Jersey, USA 07 February 2015 Cultivar from garden store Equipment [Nikon D600-broadband + Rodenstock 50mm f/3.5 Omegaron] The EXIF data in the photographs is incorrect for the lens focal length and lens speed because this lens is unchipped. Visible Light [f/11 for 1.3" @ ISO-100 in Sunlight with Baader UVIR-Block Filter] Photo may be clicked up to 1000 pixels wide. Unresized extract from preceding photo, anthers. Ultraviolet Light [f/11 for 1/1.6" @ ISO-400 with Nichia 365nm UV-LED and Baader UV-Pass Filter] All UV photographs have the same exposure. Photos may be clicked up to 1000 pixels wide. 1. 2a. 2b. Unresized extract from preceding photo, center area. 3. 4a. 4b. Unresized extract from preceding photo, stigma. 5a. 5b. Unresized extract from preceding photo, foreground petal. 6a. 6b. Unresized extract from preceding photo, topmost petal. Set 2 Middletown, New Jersey, USA 13 February 2015 Cultivar from garden store Equipment [Nikon D600-broadband + Rodenstock 60mm f/5.6 UV-Rodagon] The EXIF data in the photographs is incorrect for the lens focal length and lens speed because this lens is unchipped. Ultraviolet Light [f/11 for 3" @ ISO-400 with SB-14 UV-modified Flash and Baader UV-Pass Filter] Ultraviolet Light [Extract from preceding photo] Ultraviolet Light [f/11 for 1/30" @ ISO-400 with SB-14 UV-modified Flash and Baader UV-Pass Filter] Conversion in Photo Ninja. Ultraviolet Light [Extract from preceding photo] Ultraviolet Light [f/11 for 1/30" @ ISO-400 with SB-14 UV-modified Flash and Baader UV-Pass Filter] Alternate conversion in Capture NX2.

Dowdy, J.C. (2014) Mazus pumilus (Burm. f.) Steenis (Mazaceae) Japanese Mazus. Photographed in visible and ultraviolet also with conical cells in UV macro. http://www.ultraviol...new_post&f=553# Synonym: Mazus japonicus (Thunb.) Kuntze Common Name: Japanese mazus Location/Date Cordova, Tennessee, USA 01 August 2014 Comment/Discussion An introduced Asian species. Very small ~8mm x 3mm flowers, perhaps showy if not so tiny. Distinct dark on intermediate UV signature following visible yellow patches on the lower lip with the upper lip of the corolla mostly dark. The edge of the toothed upper lip is contrastingly UV bright as is the throat to a lesser degree. They look a bit velvety up close prompting some macro images also. The surface of the dorsum of the upper lip is predominantly covered by roughly conical (Coke bottle shaped) cells interspersed with taller smooth topped mushroom shaped structures and occasional significantly taller rough topped extensions. Taxonomic authorities are currently in disagreement as to which family this genus belongs. Initially placed in Scrophulariaceae (Figwort family) then moved to Phrymaceae (Lopseed family) and now into new family – Mazaceae. Visible light, photographed in full sunlight. Panasonic DMC-G3 full spectrum modified, CERCO UV type 2178 100mm f/2.8, 1/200 sec, ISO 160 & f/8 which is the smallest aperture for this lens, 1.25” Baader UV/IR cut filter mounted in adapter inside lens shade. Custom in camera white balance on PTFE lens cap. (Image Reference: JCD140108_Mazus_japonicus_VisPennyResized.jpg) (Image Reference: JCD140108_Mazus_japonicus_Vis-LeavesCrop.jpg) (Image Reference: JCD140108_Mazus_japonicus_Vis-QuadCrop.jpg) Ultraviolet, photographed in full sunlight. Panasonic DMC-G3 full spectrum modified, CERCO UV type 2178 100mm f/2.8, shutter 1/3 to 1 sec, ISO 160 & f/8, 1.25” Baader U filter mounted in adapter inside lens shade. Custom in camera white balance on PTFE lens cap. (Image Reference: JCD140108_Mazus_japonicus_UVPennyResized.jpg) (Image Reference: JCD140108_Mazus_japonicus_UV-QuadCrop.jpg) (Image Reference: JCD140108_Mazus_japonicus_UV-TwoAngleCrop.jpg) (Image Reference: JCD140108_Mazus_japonicus_UV-TwoFrontCrop.jpg) Conical Cells, photographed at ~5.7X, 375nm UV-LED Panasonic DMC-G3 full spectrum modified, reversed Perti 35mm f/3.5 coupled onto a Petri 200mm f/4 @ f/4, 1.25” Baader U filter mounted in coupling adapter. Long exposures 10 to 30 sec, ISO 400 & f/8-16 on the reversed 35mm. Custom in camera white balance on 1.25” 99% Specralon reflectance standard. (Image Reference: JCD140108_Mazus_japonicus_UV-ConicalCellsResized.jpg) Dorsal view, re-scaled not cropped. (Image Reference: JCD140108_Mazus_japonicus_UV-SelectedCropTwoThirdRescaleA.jpg) Selected crop re-scaled 2/3. (Image Reference: JCD140108_Mazus_japonicus_UV-SelectedCropTwoThirdRescaleB.jpg) Selected crop re-scaled 2/3. References 1., ANGIOSPERM PHYLOGENY WEBSITE, version 13. (11Sep2011). Missouri Botanical Garden, University of Missouri, St Louis, MO USA. 2. USDA, Natural Resources Conservation Service, The Plants Database. (10Sep2014) Mazus pumilus. National Plant Data Team, Greensboro, NC USA. 3., The University of Tennessee Herbarium, Database of Tennessee Vascular Plant Occurrences. (10Sep2014) Mazus pumilus, The University of Tennessee, Knoxville TN 37996. 4. Southeastern Flora, Southeastern US Plant Identification Resource. (10Sep14) Mazus pumilus Copyright© John R. Gwaltney. 5. Extreme Macro, Stacking Lenses For Macro. (10Sep14) Copyright© Johan J Ingles-Le Nobel. Published: 11Sep2014

Just a few examples of recent experiments with photomacrography in UV. I have confined myself to the range 5-10 x, which is just doable in a studio setting, and have explored the potential of fairly ordinary lenses for macro work. First example is the corolla of Lysimachia punctata (Primulaceae). Shot at 8X using the D600 (modified), 100 ISO, Baader U2"(Venus) filter, Canon 20 mm f/3.5 Macro lens head at f/5.6, and Broncolor Studio flashes (uncoated Xenon). The conical cells here are formed in shape of elongated ridges with rugose crosswalls. The long dimension of these cells are along the length of the petals. Interspersed are short, stubby glandular hairs. These hairs make the surface rough and give rise to the vernacular names such as 'Dotted' or 'Spotted' Loosestrife'. The glandular hairs are particularly plentiful along the petal edges.

Oldfield, D. 2014. Cyanicula caerulea (R. Br.) Hopper & A.P. Br. (Orchidaceae) Blue Fairy. Flowers photographed in visible and ultraviolet light. http://www.ultravioletphotography.com/content/index.php?/topic/995-cyanicula-caerulea-blue-fairy/ Maldon, Victoria, Australia Maldon Historic Reserve 17 August 2014 Australian Native Wildflower Synonym Caladenia caerulea Comment Cyanicula caerulea is a common plant of the Victorian Goldfields, frequently found in box-ironbark forests and woodlands. Visible Light: Pentax K-5 Full Spectrum Modification, Nikon Rayfact PF10545 MF-UV 105 mm f/4.5 lens, Metz 15 MS-1 flash, 1/180 s @ f/16 ISO 200, B+W UV/IR Cut Filter. Image Reference: DO53458 Ultraviolet Light: Pentax K-5 Full Spectrum Modification, Nikon Rayfact PF10545 MF-UV 105 mm f/4.5 lens, Nikon SB-14 flash, 1/180s @ f/16 ISO 200, Baader UV-Pass Filter. Image Reference: DO53461 100% magnification References: Backhouse, G. and Jeanes, J. The Orchids of Victoria, Miegunyah Press, 1995, p. 58. Ross, J.H. and Walsh, N.G. (2003) A Census of the Vascular Plants of Victoria Edn 7. Atlas of Living Australia http://bie.ala.org.a...nicula+caerulea Published 21 August 2014

Rørslett, B. 2014. Melampyrum pratense L. (Orobanchaceae). Common Cow-wheat. Flowers photographed in visible and ultraviolet light. http://www.ultraviol...mmon-cow-wheat/ Melampyrum pratense L. NO: Stormarimjelle SE: Ängkovall DK: Almindelig Kohvede FI: Kangasmaitikka DE: Wiesen-Wachtelweizen EN: Common Cow-wheat Formerly placed in the Scrophulariaceae, the hemiparasitic genus Melampyrum now is placed into the Orobanchaceae. M. pratense is native to Europe and is widely distributed from lowlands into the lower mountain ranges. In Norway it extends into Arctic regions. Although the scientific Latin name suggests it is a meadow-dwelling species, it in fact is even more common in dry forests or heath moorlands. Flowering occurs in mid summer and the corolla normally is a pale yellow with some reddish adornments, but can appear deeper yellow or near orange as well. The flowers are visited by a number of pollinators including bumblebees. The seeds contain an elaiosome and are eagerly visited by ants. Material collected at Hvaler, Norway, 4 August 2014. Image reference: MELA_PRA_B14080551473_VIS Image reference; MELA_PRA_I1408052130_UV

Rørslett, B. 2014. Impatiens parviflora DC. (Balsaminaceae). Small Balsam. Flowers photographed in visible and ultraviolet light. http://www.ultraviol...a-small-balsam/ Impatiens parviflora DC. NO: Mongolspringfrø SE: Blekbalsamin DK: Småblomstret Balsamin FI: Rikkapalsami DE: Kleines Springkraut EN: Small Balsam This small to medium-sized, up to 0.5 m tall, species originates from Central Asia and colonises shady habitats, often in rich deciduous forests. The leaves are thin and flexible and spread to capture low levels of incident light. It has become naturalised in most of Europe and elsewhere. The fruits open by a virtual explosion when touched lightly, giving rise to vernacular names such as 'touch-me-not'. Image reference: IMPA_PAR_B1407185027_VIS.jpg Visible light: Nikon Df, Voigtländer APO-Lanthar 125 mm f/2.5 lens, SB-800 flash. Image reference: IMPA_PAR_I1407182059_UV.jpg Ultraviolet light: Nikon D3200 (modified), UV-Nikkor 105 mm f/4.5 lens, Baader U2" (Venus) filter, SB-140 flash. I. parviflora has an unusual (false) tri-"colour" appearance. There are patches of conical cells around the entrance to the spur. [ Published 19 July 2014 ]

Rørslett, B. 2014. Cymbalaria muralis P. Gaertn., B. Mey. & Scherb. (Schrophulariace; Plantaginaceae). Ivy-leaved Toadflax. UV signature with conical cells. Flowers photographed in visible and ultraviolet light. http://www.ultraviol...-conical-cells/ Cymbalaria muralis P. Gaertn., B. Mey. & Scherb. Syn. Antirhinnum muralis L.; Linaria muralis (L.)Mill. NO: Murtorskemunn SE: Murreva DK: Vedbend-Torskemund FI: Kilkkaruoho DE: Zymbelkraut EN: Ivy-leaved Toadflax: Kenilworth Ivy This small creeping species is a native of southern Europe and widely used as an ornamental plant. It easily escapes from cultivation and may become naturalised even in colder climates such as in the Nordic countries. Material was collected and photographed near Oslo, Norway 13 Aug 2010. Image reference: CYMB_MUR_I1008131038_VIS.jpg Visible light: Nikon D40X (modified), UV-Nikkor 105 mm f/4.5 lens, Baader UV/IR Cut filter, daylight, m=1.5. Image reference: CYMB_MUR_I10081312423_UV.jpg Ultraviolet light: Nikon D40X (modified), UV-Nikkor 105 mm f/4.5 lens, Baader U2" (Venus) filter, Broncolor studio flash with uncoated Xenon tube. From the original file (CYMB_MUR_I10081312423_UV.tif), I made two 100% crops to show better the amazing level of detail of the epidermal structures contained therein. The first published UV signature of C. muralis was by Blum (2013): http://www.ultraviol...aved-toadflax/. My results are in principle identical, but the higher magnification discloses more details. All photographs captured with the exact same camera and lens, by the way (D40X/UV-Nikkor). Just to illustrate how much more detail UV brings with it. [ Published 15 July 2014 ]

Rørslett, B. 2014. Utricularia sandersonii Oliv. (Lentibulariaceae). Flowers photographed in visible and ultraviolet light. http://www.ultraviol...ia-sandersonii/ This is a terrestrial member of the large Utricularia genus of carnivorous plants. It is endemic to South Africa, where it occurs on wet seepage rocks. U. sandersonii has become a favourite in the community of carnivorous plant enthusiasts because it is easy to cultivate. The traps are borne on the foliage at or just below the substrate surface. I shot these plants in a terrarium in Botanical Garden of the University of Copenhagen, Denmark 29 June 2014. As access to the specimens in cultivation was limited, I had to shoot through the enclosing glass panes, so probably the UV rendition might have suffered slightly. Image reference: UTRI_SAN_B1406291528_VIS.jpg The zygomorphic corolla features two narrow upwards-pointing lobes that makes the entire flower look very 'rabbit'-like. The long curved spur adds to the visual character as well. Image reference: UTRI_SAN_I1406291885_UV.jpg The entire corolla is moderately reflective in UV. Do note that the need to shoot through a window pane may have cut back some of the UV features. Image reference: UTRI_SAN_I1406291885_UV_100pct.jpg A 100% detail from the previous photograph to indicate how the spur is densely covered with long conical cells. Ultraviolet light: Nikon D3200 (modified), Coastal Optics 60 mm f/4 APO lens, internal Baader U2" (Venus) filter, SB-140 flash. [ Published 8 July 2014]

I was recently complaining about how UV torchlight and sunlight don't mix well. So I thought I would show you this example. There's nothing earthshaking or hugely important here. Just an illustration of one of the problems that can be encountered in UV photography if using the 'wrong' equipment. My UV torch for this experiment is fitted with a high-power Nichia 365nm UV-Led. I typically use this torch for illuminating a subject in order to focus Live View through a UV-Pass filter. For this task a UV torch is indispensible. Mine is a well-made beauty - the UV-Haiku by Don MacLeish. Equipment used: Nikon D600-broadband + 105/4.5 UV-Nikkor Here is my test subject: Lewisia longipetala 'Little Plum'. (Or so it was marked. It does not look particularly plum coloured to me.) Visible: with Baader UVIR-Block filter in sunlight Ultraviolet: with Baader-U UV-Pass filter in sunlight. First the original (cropped) version, then the white-balanced version. You can see that the flower has a lot of UV-iridescence because of surface conical cells. Ultraviolet: with Baader-U UV-Pass filter in sunlight and torchlight. I was holding the torch at quite some distance from the flower in order to fully cover the flower with the beam. However, the shot appears blotch-ily bi-coloured both before and after white balancing. FIrst the original (cropped) version, then the white-balanced version. This last photo shows how I tried to desaturate the yellow false colour in the preceding white-balanced version. This almost gives a monochrome look, but not quite. Just a reminder -> a monochrome look is expected when shooting with such a narrowband UV-Led light when little or no sunlight is mixed in. Here is one more comparison. In this case, the UV torch & sunlight combo turned out better. Although not particularly monochrome, so go figure. First the sunlight-only shot, then the mixed light shot. (Both were white-balanced.) If I desaturate the yellow false colour in the preceding mixed light shot, then I also lose the greenish false colour in the leaves. This is mostly an artistic complaint, as I think we need to be careful with how we interpret false colour. Because there are flowers which do have a yellow false colour after white balancing, I think it would be difficult to know when to remove it and when not to if using this kind of mixed sunlight/torchlight.

Blum, A.G. (2013) Dahlia x hybrida Cavanilles (Asteraceae) Garden Dahlia. Flowers photographed in ultraviolet and visible light. http://www.ultraviol...-garden-dahlia/ Kinfolk Lane, Southwest Harbor, Maine, USA 11 July 2012 Cultivar in home garden Comment: The bicolouration of this hybrid Dahlia carries over to the UV photograph. Reference: 1. The American Dahlia Society (2014) Equipment [Nikon D300-broadband + Carl Zeiss 60mm f/4.0 UV-Planar] Click the photo to view at largest size. If you see a + symbol after first click, then click again. Visible Light [f/8 for 1.6" @ ISO 200 in Sunlight with Baader UVIR-Block Filter] Ultraviolet Light [f/8 for 1/60" @ ISO 400 with SB-14 UV-modified Flash and Baader UV-Pass Filter] Ultraviolet Light [f/8 for 1/60" @ ISO 400 with SB-14 UV-modified Flash and Baader UV-Pass Filter] The pollen is UV absorbing. (This photo does not enlarge if clicked.) UV-Induced Visible Fluorescence [f/8 for 3" @ ISO 500. Nichia 365 UV-Led + Baader-UV-Pass Filter. Lens + Baader UVIR-Block Filter. Photographed in Darkness.] Note: This photo has not been formally colour-calibrated, so the colours of the Fluorescence may not be entirely accurate. A little wonderland of delightful fluorescence induced by a UV torch. Ultraviolet Light [f/8 for 1/60" @ ISO 500 with SB-14 UV-modified Flash and Baader UV-Pass Filter] The conical cells are evident on the petal surface.

Rørslett, B. 2013. Anacamptis pyramidalis (L.)Rich. (Orchidaceae). Pyramidal Orchid. Plants from France. Flowers in visible and ultraviolet light. http://www.ultraviol...ramidal-orchid/ Anacamptis pyramidalis (L.)Rich. NO: Salepsrot SE: Salepsrot DK: Horndrager DE: Hundswurz EN: Pyramidal Orchid A medium tall, to 0.5 m, orchid native to Continental Europe and the British Isles..It has outposts in Denmark and Southern Sweden. Plants photographed at Olonne-sur-Mer, France 31 May 2011. Image reference: ANAC_PYR_G1105315339_VIS.jpg Visible light: Nikon D3S, Voigtländer 125 mm f/2.5 APO-Lanthar, daylight. Image reference: ANAC_PYR_I1105313551_UV.jpg Ultraviolet light: Nikon D40X, UV-Nikkor 105 mm f/4.5 lens, Baader U2" (Venus) filter, SB-140 flash. The corolla of A. pyramidalis is densely covered with high conical cells. Image reference: ANAC_PYR_I1105313554_UV.jpg Ultraviolet light: Nikon D40X, EL-Nikkor 50 mm f/2.8 stacked on UV-Nikkor 105 mm f/4.5 lens, Baader U2" (Venus) filter, SB-140 flash. Crop from a full frame. 3X magnification. References: http://www.ultraviol...ure-references/ [Published 23 June 2013]

Rørslett, B. 2013. Leucanthemum x superbum (Bergmans ex J.W.Ingram) D.H.Kent (Asteraceae). Shasta Daisy. Flowers photographed in visible and ultraviolet light. http://www.ultraviol...m-shasta-daisy/ Leucanthemum x superbum (Bergmans ex J.W.Ingram)D.H.Kent Syn. Leucanthemum lacustre (Brot.) Samp. x maximum (Ramond)DC. NO: Kjempekrage EN: Shasta Daisy A popular cultivated ornamental plant, L. x superbum is very similar to the native L. vulgare Lam. but much larger in all parts. It sometimes escapes from gardens to occur naturalised in persistent colonies on dry soils, mainly in meadows. Plants collected and photographed near Oslo, Norway, 11 Jun 2013. These specimens were naturalised on calcareous soils in a rich meadow. The post could be equally well be listed under the "Wildflowers" heading. Image reference: LEUC_SUP_I1306113651_VIS.jpg Visible light: Nikon D600 broad-spectrum, UV-Nikkor 105 mm f/4.5 lens, Baader UV/IR Cut plus B+W BG-38 filters, daylight. Image reference: LEUC_SUP_I13061137509_UV.jpg Ultraviolet light: Nikon D600 broad-spectrum, UV-Nikkor 105 mm f/4.5 lens, Baader U2" (Venus) filter, Broncolor studio flash (uncoated Xenon tube), 135 images stacked in Zerene Stacker. A 100% crop from the above to show details, L. x superbum is interesting because not that long time ago, one would dismiss it by declaring it "lacked a pattern [= UV signature]". However, better photographic techniques disclose that the ray flowers are very shiny in UV due to the presence of rugose elongated epidermal cells that act like a diffraction grating and cause iridescence as well. There are rows of conical cells mainly along the major ray veins. The disk flowers are darker but due to the presence of conical cells they reflect UV as well, depending on the angle of incidence. [Published 11 Jun 2013]

Blum, A.G. (2013) Epipactis helleborine L. Crantz (Orchidaceae) Broad-leaved Helleborine. Flowers photographed in ultraviolet and visible light and UV-induced visible fluorescence. http://www.ultraviol...ed-helleborine/ Southwest Harbor, Maine, USA 25 July 2013 Wildflower Pollinator: Wasps Synonyms: Epipactis latifolia (L.) Allioni Serapias helleborine L. Comment: This non-native (US), shade-loving, wasp-pollinated orchid can be a bit invasive if given a chance. The plant roots have a mutualistic relationship with mycorrhiza fungi. This specimen shows a visible greenish colour, but the flowers may have some pink tints also. In the UV the flower has a multi-toned appearance with the brightest area around the anther. Reference: 1. Ehlers BK, Olesen JM and Ågren J (2002) Floral morphology and reproductive success in the orchid Epipactis helleborine: regional and local across-habitat variation. Plant Systematics and Evolution. http://mit.biology.a...20Evol%2002.pdf 2. New England Wild Flower Society (2013) Epipactis helleborine (L.) Crantz. Broad-leaved Helleborine. http://gobotany.newe...is/helleborine/ Equipment [Nikon D300-broadband + Nikon f/4.5 UV-Nikkor] Visible Light [f/11 for 1" @ ISO 200 with onboard Flash and Baader UVIR-Block Filter] Ultraviolet Light [f/11 for 20" @ ISO 200 with SB-14 UV-modified Flash and Baader UV-Pass Filter] Ultraviolet-induced Visible Fluorescence [f/11 for 3" @ ISO200. Nichia 365nm UV-Led + Baader UV-Pass Filter. Lens with Baader UVIR-Block Filter. Photographed in darkness.] Note: This photo has not been formally colour-calibrated, so the colours of the Fluorescence may not be entirely accurate.

Rørslett, B. 2013. Narcissus poëticus L. (Amaryllidaceae). Poet's Narcissus. Flowers photographed in visible and ultraviolet light. http://www.ultraviol...oets-narcissus/ Narcissus poëticus L. NO: Pinselilje SE: Pingstlilja DK: Pinselilje FI: Valkonarsissi DE: Weiße Narzisse EN: Poet's Narcissus; Pheasant's-eye Daffodil A perennial plant growing from hibernating bulbs and native to Southern Europe, N. poëticus is widely cultivated as an early-flowering ornamental plant. It has scapes each supporting a large showy flower with a perianth comprising six white-coloured tepals in whorls of three and an inner short tube or corona, usually yellow-coloured with a wavy red rim. Below each flower there is a papery bract. There are a myriad of cultivars and some escape from cultivation to become naturalised on open grass land, often in parks, near urban areas. The perianth is organised in two whorls with three slighty larger outer sepals and three inner petals.There is an inner tubular structure, designated a corona. The stamens are inserted in the nectaria within the corona. Plants collected and photographed near Oslo, Norway 21-22 Apr 2011. These specimens were fully naturalised on open grasslands. Image reference: NARC_POE_I1105201095_VIS.jpg Visible light: Nikon D40X, UV-Nikkor 105 mm f/4.5 lens, Baader UV/IR Cut filter, daylight. Image reference: NARC_POE_I11051934390_UV.jpg Ultraviolet light: light: Nikon D40X, UV-Nikkor 105 mm f/4.5 lens, Baader U 2" (Venus) filter, Broncolor Minicom studio flash, uncoated Xenon tube. Eight frames stacked with Zerene Stacker software. The UV signature of N. poëticus is complex and comprises several components. Firstly, the perianth is moderately UV reflective, but a wide diversity of cell structures both within the corolla and on the tepals adds a lot of sparkle. Secondly, due to the presence of conical cells iridescence prevails all over the corolla surface. It is noteworthy that the entrance to the corona ("trumpet") is endowed with cell structures not found elsewhere on the tepals. Below are 100% crops of some of the parts of the flower, taken from the UV image above. [Published 18 May 2013]

Rørslett, B. 2013. Cardamine pratensis L. (Brassicaceae). Cuckooflower. Flowers photographed in visible and ultraviolet light. http://www.ultraviol...s-cuckooflower/ Cardamine pratensis L. (s.lat.) Syn.: C. dentata Schult., C. palustris (Wimm. & Grab.) Peterm., C. pratensis L. ssp. palustris (Wimm. & Grab.) Janch., C. pratensis L. var. palustris Wimm. & Grab., C. pratensis L. ssp. dentata (Schult.) Celak. (ssp. paludosa), C. nymanii Gand., C. pratensis L. ssp. angustifolia (Hook.) O. E. Schulz , C. pratensis L. ssp. polemonioides Rouy (ssp. angustifolia) NO: Engkarse (ssp. pratensis), sumpkarse (ssp. paludosa), polarkarse (ssp. angustifolia) SE: Ängsbräsma, ängskrasse; äkta ängsbräsma (ssp. pratensis), kärrbräsma (ssp. paludosa), polarbräsma (ssp. polemonioides) DK: Engkarse (ssp. pratensis), Sumpkarse (ssp. paludosa) FI: Luhtalitukka IS: Hrafnaklukka DE: Wiesen-Schaumkraut EN: Cuckooflower C. pratensis is a polymorphic species native to Europe and Asia. The species complex seen as a whole has a circumboreal distribution. It is mainly a species of lush meadows where it can occur abundantly to colour the landscape in pale pink, violet, or creamy white in the late spring. Other races grow in mountain biotopes, along snowbeds and brooks, and wetlands. The variabilty of C. pratensis has generated a confusing and complex nomenclature that changes back and forth over time. Some of the races are easily identifiable others are not. In the Nordic countries, ssp. pratensis, ssp. paludosa, and ssp. angustifolia, are generally accepted and can be reasonably well kept apart in the field. Image reference: CARD_PRA_L040514852_VIS.jpg Hasselblad XPan, 45 mm f/4 lens. Lush spring meadows in white or pink by cuckooflowers are ubiquitous sights in coastal regions of Norway. Plants for UV photography were collected near Oslo, Norway. They belong to ssp. pratensis which has a wide coastal and western distribution. Image reference: CARD_PRA_I1105210181_VIS.jpg Visible light: Nikon D200, UV-Nikkor 105 mm f/4.5 lens, Baader UV/IR Cut filter, daylight. Image reference: CARD_PRA_I1105210187_UV.jpg Ultraviolet light: Nikon D200, UV-Nikkor 105 mm f/4.5 lens, Baader U 2" (Venus) filter, Broncolor studio flash. In UV light, the petals of C. pratensis are moderatelu UV-reflective. There are a small basal dark patch and veins are quite UV-dark as well. Larger conical cells are concentrated along thes veins and appear light greyish on this photograph. Image reference: CARD_PRA_I1105213451_UV.jpg Ultraviolet light: Nikon D200, EL-Nikkor 50 mm f/2.8 stacked on UV-Nikkor 105 mm f/4.5 lens, Baader U 2" (Venus) filter, Broncolor studio flash. 3X magnification. The petals are rather shiny so depending on the incidence angle of light, they may become very bright. Apparently this relates to the presence of numerous smaller conical cells in the areas between the major veins. [Published 16 Apr 2013]

Rørslett, B. 2013. Alisma plantago-aquatica L. (Alismataceae). Water-plantain. Flowers photographed in visible and ultraviolet light. http://www.ultraviol...water-plantain/ Alisma plantago-aquatica L. NO: Vassgro SE: Svalting; kranssvalting DK: Vejbred-Skeblad FI: Ratamosarpio DE: Gewöhnlicher Froschlöffel EN: Water-plantain A. plantago-aquatica is an emergent macrophyte with several subspecies which together have a broad Circumboreal distribution. It is typically found in ponds, gravel pit and similar sites, or along rivers and lakeshores where some disturbance occurs. The dispersal into new habitats typically occurs very fast and it frequently is seen amoing the first colonising species of a suitable fresh aquatic location. The sites tend to be slightly enriched, but A. plantago-aqautica is also at home in fairly oligotrophic lakes. The main growth form has emergent, plantain-like foliage and comes into flowering in the early summer. Wholly submerged plants with linear strap-shaped leaves are quite common as well, and so is an intermediate stage with small floating leaves. The latter specimens sometimes are misidentified as the rare Luronium natans. The tall air-borne inflorescence carries whorls with quite small, short-lived white flowers on long stalks. Only part of the flowers are opened at any time. The petals, numbered three, are delicate and easily shed during windy or rainy days. Mainly smaller insects visit these flowers. Plants collected and photographed near Oslo, Norway 4 Aug 2010. Image reference: ALIS_PLA_I1008041062_VIS.jpg Visible light. Nikon D40X, UV-Nikkor 105 mm f/4.5 lens, Baader UV/IR Cut filter, daylight. Image reference: ALIS_PLA_I1008041231_UV.jpg Ultraviolet light. Nikon D40X, UV-Nikkor 105 mm f/4.5 lens, Baader U 2" (Venus) filter, SB-140 flash. In UV, the petals of A. plantago-aquatica exhibit a rich occurrence of conical cells which causes patches of iridesencence on their surface. A close-up from the figure above shows this phenomenon clearly, [Published 7 Feb 2013]

Rørslett, B. 2012. Barbarea vulgaris R.Br. (Brassicaceae). Winter-cress. Flowers photographed in visible and ultraviolet light. http://www.ultraviol...s-winter-cress/ Barbarea vulgaris R.Br. (s. lat.) Syn: B. vulgaris R.Br. var, arcuata (Opiz ex J. Presl & C. Presl) Fr.; .B. arcuata (Opiz ex J. Presl & C. Presl) Rchb.; B. vulgaris R. Br. ssp. arcuata (Opiz ex J. Presl & C. Presl) M. Loehr (var. arcuata), B. vulgaris R. Br. var. silvestris Fr. (var. vulgaris) NO: Vinterkarse; buevinterkarse, bogevinterkarse (var. arcuata); sørlig vinterkarse, sørleg vinterkarse (var. vulgaris) SE: Sommargyllen; vanlig vinterkarse (var. arcuata); bangyllen (var. vulgaris) DK: Almindelig Vinterkarse (var. vulgaris), Udspærret Vinterkarse (var. arcuata) FI: Peltokanankaali IS: Garðableikja DE: Echtes Barbarakraut EN: Winter-cress An early-flowering mustard native to Eurasia, it is widely distributed in the Nordic countries from the 17th Century onwards. Its habitats are usually quite dry and it thrives on calcareous rocks, road verges, fallow fields, along railroads, and other man-made habitats. Flowering commences early in May and continues into June. Being of an invasive nature, B. vulgaris can replace native vegetation and is considered a severe threat to vulnerable and endangered plant communities on thin calcareous soils in coastal areas of Norway. B. vulgaris shows dense sprays of dark yellow flowers and is eagerly visited by butterflies, hoverflies, bees, and bumblebees. One frequently observes yellow crab spiders hiding in these inflorescences ready to attack prey, usually pollen-gathering bees. The species show considerable variation and two main types are present. The two are difficult to differentiate until fruit begins to develop, then they are easily kept apart. The taxonomic treatment ranges from having two separate species to varieties of a common B. vulgaris. Material (var arcuata) collected near Oslo, 13 May 2012. [image reference: BARB_VUL_I1205240077_VIS.jpg] Visible light: Panasonic GH-2, Coastal Optics 60 mm f/4 APO lens, Baader UV/IR Cut, studio flash. [image reference: BARB_VUL_I1205240065_UV.jpg] Ultraviolet light: Panasonic GH-2, Coastal Optics 60 mm f/4 APO lens, Baader U 2" (Venus) filter, Broncolor Minicom (studio flash (uncoated xenon tube). This species may have one of the most beatiful UV patterns of all mustards. The large, dark UV marks continue into strongly prominent UV-dark veins on both sides and are even stronger present on the abaxial (lower) side of the petals. The adpressed sepals are very dark in UV and so are the buds. Photographed at high magnification, it becomes obvious that these UV marks are closely correlated with massive development of conical cells. See picture below, taken at 3 X magnification. [image reference: BARB_VUL_I1105139953_UV.jpg] Conical cell structures and UV marks on petal of B. vulgaris var. arcuata. Ultraviolet light: Nikon D40X, EL-Nikkor 50 mm f/2.8 lens stacked on UV-Nikkor 105 mm f/4.5 lens plus extension, Baader U2" (Venus) filter, Broncolor studio flash (uncoated Xenon tube). Note also the very UV-dark elongate pollen grains. [Published: 26 Dec 2012]