Hilda Canter-Lund competition winners 2018

The winner of the 2018 Hilda Canter-Lund competition for algal photography is Rafael Martín-Ledo for “Drifting diatoms”, his phase contrast image of a fragment of a colony of the diatom Licmophora, seen in a sample collected from the Bay of Santander, northern Spain, in March 2018.   There are over twenty cells attached to this branched stem, each just over a 10th of a millimetre in length.   The frond itself was probably originally attached to a seaweed in the littoral zone (see “epiphytes with epiphytes …”) but Rafael found it drifting in open water whilst using a plankton net.

Rafael trained at the University of Extremadura in Spain and started his research career with Biodiversity and Ecology of Marine Invertebrates group at the University of Seville. His primary focus during this period was the taxonomy, symbiosis and biogeography of the ophiuroids (echinoderms, including brittle stars) of Antarctic waters. After that he worked with the British Antarctic Survey in Cambridge, examining thousands of specimens from several expeditions.

Rafael Martín-Ledo: 2018 Hilda Canter-Lund competition winner.

He currently lives in Santander, working as an independent researcher with a particular interest in marine plankton. A personal project to document the larvae of planktonic invertebrates has led to the production of hundreds of images shared through a personal website, a YouTube channel (his videos of marine organisms are also of a very high quality) and a Twitter account (@rmartinledo). The primary motivation is taxonomic but a by-product of this is to make people aware of the great morphological beauty of lesser-known marine organisms.   Some other examples of his work are reproduced below.

 

More examples of Rafael’s photomicroscopy skills:
a. Larva, nectochaete stage, of Glycera alba (polychaete). DIC microscopy, 200x magnification;
b. Pilidium larva, gyrans type, of nemertean worm. DIC microscopy, 200x magnification;
c. Ascidian embryo (tunicate). DIC microscopy, 400x magnification; and,
d. Cymbasoma thompsonii, female with eggs (copepod). Polarization microscopy, 40x magnification.

More examples of Rafael’s photomicroscopy skills:
e. Tripos candelabrus (dinoflagellate). DIC microscopy, 200x magnification; and,
f. Zoothamnium pelagicum (colonial ciliate). Phase Contrast microscopy, 200x magnification.

The second prize this year, awarded to the photographer of an image in a contrasting style, goes to John Huisman, an old friend of the competition who has been on the shortlist several times, winning in 2014.  John is based in Perth, Western Australia and this photograph was taken during a trip to Ashmore Reef off the northern coast of Western Australia.   His motivation is to document the marine flora of this remote region, and the image shows a new species from the red algal genus Ganonema.  Ganonema is a genus of calcified, often mucilaginous red algae, the calcification occurring as granules in the cortex and not forming a firm skeleton. At Ashmore the new species was growing in coarse coral rubble at 12 metres depth. The photograph was taken while SCUBA diving, with a Nikon Coolpix P7100 in a housing with twin Inon strobes providing fill flash.

A new Ganonema: John Huisman’s prize-winning entry for the 2018 Hilda Canter-Lund competition.

You can see these and all other winners and shortlisted images since the competition started in 2009 at the Hilda Canter-Lund pages of the British Phycological Society’s website.

John Huisman: 2014 winner and 2018 second prize winner

 

 

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Hilda Canter-Lund shortlist 2018

We’ve just put the shortlist for the 2018 Hilda Canter-Lund prize onto the BPS website and voting is now underway to determine the winners.   As in previous years, we had a lot of images of marine macroalgae and rather fewer of microalgae, which is a problem that I’ve tried to address in a few posts over the years (see, for example, “How to win the Hilda Canter-Lund competition (3)”.  However, the best of the micrographs were stunning and two are included on the shortlist, though they have some stiff competition.  I’ll go through the shortlisted images in alphabetical order.  In each case, I have included a thumbnail, but you can see better quality images at http://www.brphycsoc.org/Canter_Lund_2018/index.lasso.

Kristen Brown of the University of Queensland kicks off our shortlist with an image of the green alga Chlorodesmis fastigiata on top of a coral.  Like many of our shortlisted images over the years it has both aesthetic qualities and tells a story as interactions between macroalgae and coral are believed to play fundamental role in the degradation of coral reefs.    Kristen is lucky enough to have a job that lets her dive on the Great Barrier Reef in Australia; our second shortlisted photographer, by contrast, dives in rather cooler waters.   José M. Fariñas-Franco was returning from a dive off Aillwee, in the Connemara region, Ireland when he took his photograph of a floating kelp forest at high tide.  The low light gives his image a particularly atmospheric appearance.

The next two images are both by photographers who have appeared on Hilda Canter-Lund shortlists before: Karie Holterman and John Huisman.   Karie Holterman, who was last on the shortlist in 2011, uses fluorescence microscopy to show cyanobacterial (blue-green algal) filaments growing amidst a mat of benthic diatoms from the bed of a lake in California.  The chlorophyll in the diatoms fluouresces with a red colour whilst DNA in the cyanobacteria pigments has been stained with Syber Green 1 to highlight its DNA.   The result is one of those intriguing images that crops up in the competition from time to time, balancing a fine line between representation and abstraction.

John Huisman is a regular fixture on the Hilda Canter-Lund shortlist, winning in 2014.  His entry this year takes us to a coral reef on the other side of Australia to the Great Barrier Reef and shows a calcified red alga, Ganonema, growing at a depth of 12 metres.

We return to the microscopic world for our next image: a frond of cells of the diatom Licmophora found drifting in the Bay of Santander in northern Spain by Rafael Martín-Ledo of the University of Extremadura in Badajoz.   Licmophora is a diatom most often found as an epiphyte on seaweeds in the littoral zone but Rafael’s frond was free-floating, perhaps having become detached from its substratum.   Rafael is a marine biologist whose interests stray well beyond algae and his Twitter feed (@martinledo) is well worth following for the wealth of beautiful images that he posts.

And finally we have an image by another old friend of the competition, Leah Reidenbach (shortlisted in 2016).  Leah’s photograph shows the green alga Ulva along with some mussels set against a background of pearl-white sand in the Bay of Fires Conservation Area in Tasmania.   There is nothing particularly exciting about any of the components of this picture but Leah’s photograph captures these in a pleasing, semi-abstract arrangement.

You may note one conspicuous absence from the shortlist this year: Chris Carter, who won in 2013 and 2017 and was shortlisted in 2010, 2011 and 2016 has now joined myself, Juliet Brodie and David Mann on the panel of judges who compile the shortlist.  The final step will be for the BPS council to vote for the winner and that should take a couple of weeks, so keep an eye out on ALGAE-L and Twitter for an announcement before too long.

And get photographing … the 2019 competition will be starting in just 10 months time…

Hilda Canter-Lund competition 2018

The competition for the 2018 Hilda Canter-Lund Award is now underway and you have until 25 May to submit images of algae – microscopic or macroscopic, marine or freshwater – for consideration.  I’ve written several posts over the last few years with advice on what makes a great image of an algae and thought that it might be useful to list them all here.   Although I suspect that the winning photograph is already nestling on someone’s hard drive, careful use of editing software could well make the difference between an image that gets onto the shortlist and one that does not.  So, read on:

How to win the Hilda Canter-Lund competition

How to win the Hilda Canter-Lund competition (2)

How to win the Hilda Canter-Lund competition (3)

How to win the Hilda-Canter-Lund competition (4)

Finally, you may find inspiration in the archive of previous winners and short-listed entires on the British Phycological Society’s website.

Good luck!

(The image at the top of this post is Luis Henriquez’s short-listed entry from last year showing Carpoglossum confluens emerging from a mass of Caulpera triferia in the coastal waters off Tasmania.)

Challenging art …

I took the opportunity of a trip to London to slip into the Hayward Gallery to have a look at the Andreas Gursky retrospective.   I’ve been interested in Gursky for some time as, like fellow German Anselm Kiefer, he is someone who uses his art to ask big questions (see “The fine art of asking big questions” and “Anselm Kiefer and the art of algae”).  Gursky is principally a photographer rather than painter or sculptor though, like Kiefer, he works at large scales.  The Rhine II, the picture at the top of this post, is 3.5 m long and 2 metres high, for example.   Taking a picture on a mobile phone doesn’t really do it justice, particularly as Gursky’s works, though they look naturalistic, are the result of extensive digital manipulation.   In this case, he has turned a landscape of the River Rhine near Dusseldorf into a near-abstract composition.   This involved digital manipulation to remove all evidence of buildings on the far side of the river.

The next picture I’ve included is the type of image for which Gursky is best-known: monumental images taken from a high viewpoint and teeming with activities associated with global capitalism.   In this case, he has photographed a factory in Vietnam that is making cane furniture for IKEA.   I look at this work as a descendent of Bruegel’s busy pictures from the sixteenth century except that Gursky’s narrative is very different to anything that Bruegel tried to portray.   Here, the sea of identically-attired individuals all performing variations of the same basic processes merge into a repetitive abstract pattern.   It is the antithesis of Cartier-Bresson’s “decisive moment” not just because there is no single “moment” that is being captured but also because the impression of spontaneity is also false: these large images are, in fact, composed from many different images.  It is not always apparent on first viewing but close examination reveals the images to be uniformly in focus from front to back and, in the case of the panoramic views, to have no issues with distortion at the edges.   So Gursky also takes us to that ambiguous territory where images look like they are depicting an actual point in space and time but they are not yet, at the same time, they are conveying truths about the modern world.   We approach his work with an expectation that photographs represent reality.  But they don’t.  Or do they?

Andreas Gursky, 2004, Nha Trang.   295 x 207 cm

Les Mées is another example of a superficially simple image of an enormous solar farm in southern France, with the Alps as a backdrop.  Once again, however, there is post-production manipulation of the image but also, in part a consequence of scale, the invitation for the viewer to contemplate and meditate on what is portrayed.  Here we have the juxtaposition between the regular, angular solar panels completely covering the hillsides in the foreground, and the natural beauty of the Alps behind.   The manmade looks that much more artificial through the juxtaposition with the grandeur of the mountains.   One of the ironies of the image is that solar panels represent a sustainable future yet are, in this location, as much of a visual pollutant as an oil refinery.   This solar farm covers 200 hectares and generates enough electricity to power 12,000 households.  How many more of these would be needed to break the West’s dependence on oil and how many more landscapes would be changed as a result?   Energy always has comes at a price.

Gursky’s talent is to simultaneously draw viewers in to inspect the details whilst forcing them to step back and absorb the whole.  As you realise from the details that the image may not be exactly what first impressions suggest, so your mind is opened to other readings.   We look at these images both as technical creations in their own right but also as commentaries on the state of the world.   Gursky manages to simultaneously challenge our eyes and our thinking.

Andreas Gursky (2016) Les Mées.  221 x 367 cm.

Coda: A week after visiting the Gursky retrospective, I saw The Square at the Tyneside cinema.  If you have not heard of this film, it is a film about a contemporary art gallery directed by Ruben Őstland.   The plot focuses on the curator of a contemporary art gallery who is trying to present high-minded conceptual art with a moral message relevant to our times so it was hard not to escape the parallels with the Gursky retrospective.   Much of the dark humour in the film arises from the curator’s inability to reconcile these high ideals with his own private life (one of the key sequences involves a one night stand with a journalist – played by Elisabeth Moss – whose name he subsequently cannot remember).   One gets a sense when seeing art in the hushed sepulchres that are contemporary art galleries that these have a quasi-spiritual role in a largely secular age.   I have no problem with this, especially if the art makes people think about their place in the modern world.  But that does place a great responsibility on the artists and curators, in turn creating the potential for storylines such as that in The Square.   Ruben Őstland has done for contemporary art what Graham Greene was so good at doing for the Roman Catholic church: highlighting the paradoxes that are inevitable when fallible humans struggle to address the biggest questions of all.

How to win the Hilda Canter-Lund competition (4)

Daniella Schatz’ image of the coccolithophore Emiliania huxleyi is one of a relatively small number of electron micrographs to have made it to the shortlist of the Hilda Canter-Lund prize and, though not an outright winner, it offers some useful lessons to anyone considering submitting an image in next year’s competition.

The first point to note is that Daniella has not submitted a single image, but a montage of two separate images. The competition rules state that “basic image enhancement (i.e. cropping, adjustment of contrast, colour balance etc) is permitted, along with focus stacking and stitching. However, excessive image manipulation is not acceptable.”   “Excessive image manipulation” is not easy to define; however, Daniella’s montage worked for the judges because the two elements together tell a story about the life of this alga.  The left- and right-hand images are the “before” and “after” cases of a major factor controlling the ecology of Emiliania huxleyi.  Daniella wanted to tell the story of the decline and fall of E. huxleyi blooms in the oceans; in the process she also evoked a long tradition of memento mori – artworks that remind viewers of their own mortality, and of the fragility of all life on earth. Another montage, this time by Alizée Mauffey, made it to the short list in 2017; again, the images were not selected and placed for aesthetic reasons, but to illustrate the range of functional traits within intertidal macroalgae.

Daniella piles on a little more “image manipulation” by using false colour to highlight the tiny EhV201 virus cells that are scattered across the right hand cell and which are responsible for its sorry state.  A couple of SEMs that have been enhanced by false colour are submitted each year but the artificiality of the medium rarely results in a major improvement to the image.  The stark monochrome of SEMs places them in a long and noble tradition of black and white photography that should not need this type of enhancement.   She, however, challenges this by using false colour very sparingly and to draw attention to an important element of her story.

And so to the “story”: we now ask all entries to the competition to be accompanied by a legend of about 100 words explaining a little more about the picture.   Most experienced phycologists will recognise the left hand image as a coccolithophore but many viewers will see these as abstract geometric shapes. The legend is important to help the viewer decode these shapes and place them into a broader context; in this case, by emphasising their role in global carbon cycling.  Having said that, most of the shortlisting takes place without reference to the legend with initial screening based primarily on the quality of the images.  I do remember, however, that Daniella’s image was one where we did need the legend in order to understand what she was trying to say.

A detail from Daniella Schatz’ Scanning Electron Micrograph (SEM) of the coccolithophore Emiliania huxleyi showing the large dsDNA Emiliania huxleyi virus (EhV201, coloured orange). EhV is a large dsDNA virus that is responsible for the demise of vast oceanic blooms of E. huxleyi. During viral infection the cells undergo programmed cell death and shed their coccoliths, important components of the carbon cycle.  The individual viruses are each about 100 nanometres (1/10000th of a millimetre) in diameter.

We also encourage photographers, particularly those submitting microscopic images, to include a measure of scale in the legend, particularly for microscopic images.  This is important, as lay audiences will have little idea about the size of the objects that are being portrayed.   When images are used as illustrations, then a scale bar is appropriate (see “The stresses of summertime …” for a recent example); however, a scale bar is likely to be an unwelcome intrusion in an otherwise balanced composition so a sentence in the legend is usually more appropriate.   Remember that the term “micrometre” might not be easily understood by many viewers, and it is a good idea to explain dimensions in millimetres as well.

When the votes were counted in 2015, Daniella’s image lost out to Günter Forsterra’s stunning view of the Beagle Channel off the coast of Chile.  However, it stands as a fine example of conceptual approach to the Hilda Canter-Lund competition – with several different elements combining to convey an idea that is more than the sum of its parts.   The photographer of the microscopic world rarely has the luxury of the “decisive moment” and, instead, the quality of the final image often lies as much in post-production as it does in image capture.

Hilda Canter-Lund competition 2017 winners

The winner of the 2017 Hilda Canter-Lund photography competition is Chris Carter for his image of the desmid Pleurotaenium coronatum var. robustum.   This is the second time that Chris has won the competition and his fifth time on the shortlist, confirming an already impressive reputation as a photographer of the algal world.   This particular image is of a specimen that was collected whilst on holiday in Newfoundland, Canada, and preserved in formalin.  This led to the loss of chloroplast colour but which, in turn, made the pore field at the end of the cell more obvious.

The technical skill behind this image is not immediately obvious unless you know the genus Pleuotaenium typically consists of cylindrical cells several times longer than wide.  This particular specimen is 45 micrometres (about 1/20th of a millimetre) in diameter but is almost half a millimetre long.  The challenge was increased because the 100x magnification oil-immersion objective which he used has a very shallow depth of field.  Chris had to suspend the cell in dilute jelly in a cavity tank not much deeper than its length.  Having done this, he agitated the cell with a length of fine wire and once it was no longer horizontal he could manipulate it by gently sliding the coverslip relative to the cell.  The photograph which won the competition is one of many attempts and, even so, Chris commented that the cell is probably a degree or so away from vertical even here but, he went on: “I thought the lighting was actually quite attractive with the bronze hue of the preserved wall contrasting with a blue tinge from the light source; even the very slight tilt perhaps suggests a monster (or a something) rising out of the deep.”

Pleurotaenium coronatum var. robustum.  The top left image is an apical view, showing the pores and the radial ring of tubercules (knobbly projections).  The lower image shows the cell in plane view.   All images by Chris Carter.

Chris Carter, Hilda Canter-Lund prize winner, 2013 and 2017.

The second prize this year was also awarded to a former winner.  Tiff Stephens won the competition last year with her photograph of Durvillaea antarctica in the intertidal zone of the sub-Antarctic Snares Islands.  This year, it was her photograph of the red alga Bonnemaisonia clavata that caught the judge’s eye.   This is a very different style of photograph to her winning entry from last year, taken using an Olympus DP20 camera on a dissecting microscope.   The row of spheres along the secondary axis (“stem”) contain female reproductive cells and the prominent branchlet in the centre right is 1.5 mm long.

“Cystocarp Central”: Tiffany Stephen’s winning entry for the 2017 Hilda Canter-Lund photography competition. 

Though the style of the picture is very different to last year’s entry, it shares with that image an encapsulation of the “decisive moment” (see “How to win the Hilda Canter-Lund competition”). Tiff comments that many of her images are “opportunistically taken while sprinting around doing fieldwork”.  In this particular case, she was on a fun dive outside of Victoria, British Columbia (Canada), collecting seaweeds to look at later, with a view to possibly making herbarium pressings.   She saw dense lumps of Bonnemaisonia clavata, a species with which she was not familiar, at depths between 5 and 10 metres on semi-exposed reefs and collected some to have a closer look later.

The two images represent the two extremes of photographing the microscopic world: Chris applied a great deal of technical skill and ingenuity to create an aesthetically-pleasing image from difficult subject matter whilst Tiff saw an elegant composition drift into view as she scanned around recently-collected field material.  Both photographers have an “eye” for a good composition and the patience and technical skill needed to capture a fine image when the occasion final presented itself.   They are also – and this is important – keen field scientists, grabbing samples out of sheer curiosity and then marvelling as new and fantastical worlds open up to them under the microscope.  Both worthy winners and, with John Huisman (winner in 2014, shortlisted five times), now form algal photography’s “superleague”: the people to beat in 2018!

Tiff Stephens surrounded by Macrocystis in Alaska earlier this year.  Follow Tiff on Twitter at @tiffanybot to see more examples of her photography.

How to win the Hilda Canter-Lund competition (3)

My two previous posts on the qualities that make a great image of an alga focussed on the ascetics of the image itself, and also identified major technical problems that confront those of us who want to take images of the microscopic world.   At this point, my own ability to write authoritatively on the subject peters out, so I have asked Chris Carter, who won the competition in 2013 and was shortlisted in 2010, 2011 and 2015, to write a guest post in which he shares his own extensive experience.

“Everything in optics is against the microscope photographer”: a guest post by Chris Carter

Chris-Carter

Everything in optics is against the photographer of the microscopic world, and the algal photographer in particular. Without cheating, there is limited scope to choose what is (or is not); in the field of view; the depth of focus is usually tight; the object size rarely matches the available field; no microscope objective can match the usable pixel count of a modern camera lens in conventional photography, and colours are, to say the least, difficult. Transmitted light photography has the additional problem of Beer’s law (remember!): make an object three times thicker and it will let through a ninth of the light, creating problems with the dynamic range.

The bottom line is that “adjustments” and some degree of image manipulation are necessary but these, in turn, place an onus on the photographer not to be dishonest with either the viewer or the organism.  The extent to which image manipulation is acceptable will depend upon whether the image is for a respected scientific journal, a competition, or for a Christmas Card. We cannot be too purist: the camera always lies and a modern digital camera works wonders in the background; what is colour anyway but an illusion derived from the eye and brain? For the holiday snapshot you are allowed to move the glass of beer out of the field of view first but you are not allowed to paste in a missing family member (or vice versa!) later. For the microscope image I suggest it is acceptable to remove objects that are spurious (e.g. floating limescale) and to use software tools to fuse images of the same object tastefully and honestly in the horizontal and vertical planes. In contrast, it is all too easy to add objects to an image to give a nice montage (e.g. of sparsely distributed planktonic forms) or to use false colours in an area that can be defined exactly by some other method. Similarly, other ‘composite’ images ( e.g. two views of the same object) have a place but may be difficult to make visually pleasing.

So, how do we go about this? The first necessity is to use a good image processing software package: there are lots of them and it isn’t easy to choose. I use Adobe Photoshop CS6. The first steps in processing a single image are to get the colours about right (there are separate sliders for each of the primary colours and filters for warming and cooling); for an image in transmitted light there will be overly dark and overly bright areas which the ‘shadow-highlight’ tool may fix easily. In more difficult cases adjustment the parameter ‘gamma’ can help: this tries to scale the dynamic range in the image to what is seen by the eye and to what comes over in a print or on a monitor: it is merely overcoming the limitations of the electronic and optical gadgets in use. Similar actions are performed by the ‘curves’ and ‘levels’ control: each allows the user to choose which colours and in which intensity to best convey information about the object in an aesthetic way whilst not wrecking its essential nature. At each pixel and in each primary colour the data will be stored as a (usually) 8 bit number giving 255 levels in total.  These levels need not be evenly spaced; ‘gamma’ for example can give more emphasis to the dark or the light areas whilst the other settings control which levels are used. Most digital cameras will be doing this in the background (even on a ‘raw’ setting) but my own camera does no pre-processing at all, which has advantages and disadvantages.

So much for colour: but there are still issues associated with depth of focus and field of view that need to be sorted out; these are both relatively easy to overcome technically but can create a considerable amount of work and have the potential to create taxonomic and artistic mayhem. I use two methods for producing images with an extended depth of focus both using separate images taken over the range of focus that is needed. The first is to use a ‘stacking’ software package such as ‘Helicon Focus’ (but there are others) and the second is to make use of ‘layers’ in Photoshop: each of these methods has its pros and cons but both need honesty and good sense as well as an eye on the “why am I doing this?” question.

Stacking with Helicon Focus tends to work better at lower magnifications: with a x100 oil objective curvature changes rapidly with focus and great care is needed; the software is easily confused and I did once introduce an extra row of punctae into a diatom! Good results at low magnification can be obtained with macroalgae such as the stoneworts, but even here taxonomic information can be lost in the process (e.g. the height difference between the primary and secondary cortex rows and the location of the spine cells). As I hinted above, there is always an ongoing and unresolved tension between the artist, the microscopist and the taxonomist!  At intermediate magnifications an image produced using Helicon Focus can look overly flat and artificial, despite being sharp. My own approach is to use a gentle touch to produce pictures that are primarily useful but very occasionally develop into an artistic masterpiece! By contrast, using “layers” in Photoshop requires human intervention to ‘paint in’ the wanted parts of different images.  For example, the desmid Micrasterias will rarely present in a sufficiently flat plane for a good image at high magnification; however, it is easy to judge what is closest to reality and to blend this in. Even here there are pitfalls: the end of the polar lobe in some species is normally out of plane or twisted….so again, what is the image for? A similar comment applies to the colonial green alga Pediastrum in which the peripheral cells have horns that are alternately up and down and the central cells often have surface granules.

micrasterias-crux-melitensi

The desmid Micrasterias crux-melintensis has many named forms and is fairly easily recognised.  It will never sit flat enough for a x100 oil lens but in this case nothing is lost by tasteful flattening with Helicon Focus  and layers. Or is it? How many people have seen the somewhat surprising apical and side views? (No wonder it does not sit flat!). These extra views show the need for gamma adjustment and colour correction since light beams will be modified after passing through such an object. Is this composite image of artistic or of taxonomic value only? The face view is made of 17 sub-images processed as two semi-cells that were stitched using Photoshop layers; some correction to colours and levels was also necessary.

thumbnail_pediastrum-boryan

There are many forms of Pediastrum boryanum but this is a particularly pretty one from Ulva growing on a wet cliff face; the red walls are real (perhaps manganese as suggested by Brian Whitton). This image borders on “cheating”: it was entered (no success) for a national wildlife contest but not for Hilda Canter-Lund competition (I don’t think she would have approved!). Should the horns have been flattened or left as obviously alternating?

After the issue of focus, there is still the problem of field-of view but it is really fairly easy to stitch together a matrix of images in the same plane, at least in simple cases. Photoshop has an option to do this and there are other similar packages; this is also another job that ‘layers’ in Photoshop cope with very well: adjacent overlapping images can be blended manually. It is more difficult of course if these adjacent images are themselves blends at different focus points……it just takes a long time to get right. The image of Tolypella glomerata that was a runner-up in the 2015 Hilda Canter-Lund competition was made of 75 sub-images (17×5 approx) and took two days to process! Each of the 17 in the xy plane was shot as a stereo pair, so there is also a matching anaglyph (3D image) made of 150 sub-images!

chris_carter_tolypella_hcl_

“Out of the pit”: Chris Carter’s image of Tolypella glomerata, shortlisted for the 2013 Hilda Canter-Lund prize.

thumbnail_chara-fragifera-a

This dark-field image showing the antheridia of Chara fragifera is made up of 28 sub-images: 4 horizontally and 7 for the vertical stacking; a protruding green filament has been removed (actually a rare Bulbochaete, but that is another story).

One final point, unresolved in my view and perhaps the most difficult of all is the issue of dynamic range. In transmitted light photography the intensity of difference between bright and dark can be nearly impossible to capture: well beyond the capability of the 8 bits of a normal camera and marginal even for an expensive cooled CCD instrument. Photoshop and other packages claim HDR ability (High Dynamic Range) using several images of different exposure: I have not personally had much success with this but have regularly used Photoshop layers to blend such images manually and regard this as acceptable in all cases (see the Rivularia cross-section below).

All the algae are amazing but even a retired physical scientist has to narrow things down a bit: I am trying to use photography to bring out the three dimensional aspects for identification and appreciation: diatom auxospores, desmids from unusual angles and macroalgae as 3D recreations such as anaglyphs and stereograms….but that is another story.

thumbnail_rivularia-xsect3

The cyanobacterium Rivularia presents many photographic challenges. This is a section of a nodule in transmitted light done for taxonomic purposes: in-focus bits of the calcification have been discretely blended in and the outermost part showing hairs is at a very different exposure to the core; colours are distorted by passing through the nodule and have been corrected. Three or four overlapping sections have been accurately joined to produce the final image.

Chris Carter, Nothampton August 2016.