Infrared inspiration

I took my FujiFilm IS-Pro camera with me on a recent trip to Brecon in Wales. This included a restful trip along the Monmouthshire and Brecon canal and, at one point, the canal crosses the River Usk on an aqueduct. The view from here, back towards the town, shows a bridge carrying the B4558 road across the river, with the Usk banked by mature trees. It made for an atmospheric infrared photo.

There was a conscious effort on my part to emulate a photograph that had got me enthused about infrared photography, many years before, and had stuck in my memory. It was in a scientific encyclopaedia and was part of a pair to illustrate a view in both infrared and blue/ultraviolet light, to show the difference.

What I later discovered was that the photograph was probably taken by Kenneth Mees of the Kodak Research Lab and also appears in his 1936 book just called 'Photography' and published by Bell and Sons in London. It is just captioned as a landscape but, in fact, the photograph is of the Veterans Memorial Bridge in Rochester, New York, the home of Kodak. Here it is ...

It seems that no copy of this image exists in the Kodak archives, but the bridge is sill there of course. It was completed in 1931 so was quite new when the photograph was taken.

This was my introduction to infrared photography. What was yours?

Frogs and leaf growth

Back in January I noted research by into infrared reflectance of insects carried out by Michael Mielewczik and others. Michael has contacted me again about two more papers on similar subjects.

The first is Non-Invasive Measurement of Frog Skin Reflectivity in High Spatial Resolution Using a Dual Hyperspectral Approach [1] (on PLOS ONE here with a PDF here).



As before, the team used a camera with filtering that split near-infrared (specifically the red-edge between 675-775 nm) and blue to explore the 'colour' of frog skin. They also used a two further hyperspectral cameras sensitive to visible and near-infrared between 400 and 1000 nm and to SWIR (short wave infrared) between 1000 and 2500 nm. This image is of agalychnis callidryas using the red-edge camera.

I've come across hyperspectral cameras before and they're quite fascinating devices. They produce a multi-dimensional image where each of the pixels in the x and y plane have a complete spectrum recorded in the z axis ... so z records intensity at a range of wavelengths. This means that you can choose which wavelength (or wavelengths) to view the scene after the fact. This multiplies the amount of data dramatically of course.

The second paper uses infrared imaging to help a study of leaf growth. The paper is Diel leaf growth of soybean: a novel method to analyze two-dimensional leaf expansion in high temporal resolution based on a marker tracking approach (Martrack Leaf) [2], available on the Plant Methods web site. This study used dark beads attached to the margins of a leaf and a camera fitted with a 940nm narrow bandpass filter. At this wavelength the leaf is brighter than the beads which makes image analysis easier.

[1] Pinto F, Mielewczik M, Liebisch F, Walter A, Greven H, et al. (2013) PLoS ONE 8(9): e73234. doi:10.1371/journal.pone.0073234
[2] Mielewczik M, Friedli M, Kirchgessner N, Walter A. Plant Methods 2013, 9:30 doi:10.1186/1746-4811-9-30

[Note: corrected information about the hyperspectral camera added 31 October]

The physics of near-infrared photography

Klaus Mangold (a photographer), Joseph A Shaw and Michael Vollmer (who are physicists) have just published a paper, The physics of near-infrared photography in the European Journal of Physics. This is the best technical paper on the subject that I've seen since Clark's book Photography by Infrared (which went out of print in 1984).

The European Journal of Physics has a policy of making papers freely available for 30 days from publication, although you will need to set up an online account to access it.

Amongst other things the paper tells us that red wine, Diet Coke and even espresso coffee are transparent to near-infrared wavelengths.

This is the URL: stacks.iop.org/EJP/34/S51

The citation is Eur. J. Phys. 34 (2013) S51–S71

The Pi NoIR: inexpensive nocturnal wildlife video

A further quick camera-related post. Andrew Back, an enthusiast for open hardware, has been using a Raspberry Pi (the tiny cheap computer) with an unfiltered CMOS imaging chip to shoot night-time wildlife. In this case it's, so far, mostly slugs and bugs caught using time-lapse photography.

See all the gory detail on the Design Spark blog.

30 October: Andrew continues posting his results on the Design Spark blog. Here's a time-lapse movie of the landscape near Hebden Bridge.

Thermal imaging reveals wildlife secrets

The BBC's new natural history series The Great British Year has shown some fascinating, and very artistic, uses of thermal imagery. (Best if you expand the videos ... but sorry they probably won't work outside the UK.)



And there's a movie showing something of the technology.



Shows you don't have to wander the plains of Africa to get exciting thermal footage, and I have to say it's nice to see something more subtle than the usual blue/red heat pattern. Also worth a read (and with the 'usual' colouring in many cases) is a web page on 10 wildlife secrets revealed by thermal cameras ... even a hot plant!

New IR camera is user-configurable

New near-infrared cameras are few and far between and there is an increasing choice of thermal imagers, even if they tend (with a notable exception) to be very expensive. However, cameras working in the gap between the two are much rarer beasts.

Episensors of Bolingbrook, Illinois have announced a new camera working in the short wave infrared (which lies just beyond photographic/near infrared) and which is intriguing, not just because they describe it as 'low cost' (not sure just how low) but also because of its versatility. Here's a paragraph from their press-release.

The infrared camera company Episensors, Inc. recently launched a new type of portable infrared camera called the Night SWEEP-1 (“NS-1”). Infrared cameras can see light that is invisible to the human eye and provide imaging at night and through obscurants like smoke and fog. What sets NS-1 apart is its portability and customizability, which allows scientists, researchers, and others to utilize the camera in the field, without sacrificing the capability of swapping between short-wave, mid-wave and long-wave infrared focal plane arrays, lenses and other components. Based on a patent-pending design, this infrared camera system is fully customizable. The camera can be configured with a pour fill Dewar or a closed cycle Integrated Dewar Cooler Assembly (IDCA) depending on the customer’s preference.

An excellent technical note on their web site explains the wavelength domain this camera covers. It's notable not just because the user can change the imaged band but that the extended SWIR (short-wave-ir) band, between 1 and 3 µm (1000 and 3000 nm) not only has some haze and smoke penetration ability but also contains a sweet spot where there is some smoke penetration but also the radiation goes through glass. Output resolution is 320 by 256 with plans for 640 by 512. The digital resolution is 14 bit and I assume having a supercooled sensor (that Dewar referred to in the note is a thermos flask of something like liquid nitrogen) will give a low noise floor.

So this camera is a kind of infrared SLR and operates between photographic infrared (which ends around 1500 nm) and the thermal bands and operates using reflected radiation (from the sun for example) while thermal imagers show radiation from the objects themselves. I believe this mid-infrared imaging is sometimes referred to as reflectography and has applications in art restoration amongst other things.

Check out the videos on the web site. They look like photographic infrared rather than thermal but you will notice some smoke penetration. It'll come down to particle size and by configuring the camera the user will be able to balance haze and smoke penetration against things like glass transparency. The nearest I've seen to this in other devices is where a single unit combines two different cameras.

Whether we will see the NS1 on this side of the Atlantic is currently debatable as some of the technology is export-restricted.

Michael Nichols lions

I know from the work of Colin Jackson at the BBC Natural History Unit that you get some fascinating shots using infrared cameras with lions at night. You would imagine that National Geographic would also come up with something impressive when covering the same subject.

Michael Nichols spent months photographing lions on the Serengeti and I'll do no more than direct you to a page of his images (some infrared) on the NatGeo web site ... especially a mesmerising shot of a lion called C-Boy. The accompanying piece appeared in the August 2013 edition of the magazine.

I'll be returning to the annals of National Geographic in future posts as they played a significant role in several historic infrared imaging adventures.

DSLR infrared sensor response

Camera manufacturers tend to be coy about releasing the spectral response of their sensors: they're (logically) more concerned about how the camera as a whole performs than how the sensor might deal with infrared (or UV).

A peek behind that curtain has come courtesy of Christian Mauer of the University of Applied Sciences in Cologne. His thesis Measurement of the spectral response of digital cameras with a set of interference filters (January 2009) is interesting in its own right but if you work your way down to Appendix A page 81 (section A.1.7) you will find the spectral response of a Canon EOS 450D without its IR blocking filter. It shows the usual bump in blue response just beyond 650 nm so that the respective responses of the red, green and blue channels at 800 nm are around 20%, 30% and 40% of the peak green response (at 540 nm) respectively. All channels come together at 20% at 850 nm and the response is monochromatic beyond that.

These figures are actually showing the spectral response of the sensor plus its Beyer filtering, since the underlying sensor is monochromatic and should have a smooth response curve peaking at around 600 nm and slowly dying away to over 1000 nm. However, this explains the strange colours when you take infrared images through a 720 nm filter and why ones through an 850 nm or longer filter are colourless.

60 megapixels of near-infrared

Back in April, I wrote about the Leaf Credo wide spectrum backs which had been set up to shoot near infrared out of the box at resolutions up to 80 megapixels. Yair Shahar (from Leaf) and I spent a couple of hours on Primrose Hill in London trying the 60 megapixel version out with both a Mamiya body and a technical camera.

The image as shot with the 60 mp back is an extraordinary 8984 by 6732 pixels. With a suitable lens the resolution is also impressive, giving scope for huge detailed prints. To give you an idea, here is a 6200 by 4000 crop from a shot through a 950 nm filter looking south from Primrose hill directly towards the Shard.

If I zoom in on this until you're looking at it pixel for pixel, this is what you see just to the left of centre on the horizon, between the two dark buildings to the left of the Shard.

This was with a Mamiya 80m lens (half a second at f9, ISO 50). With a technical camera lens the image was even sharper. I have found that infrared can produce very interesting cloud images even on an overcast day, presumably because of a different balance between the brightness of the ground/trees (which show up bright in infrared due to the Wood Effect) and the cloud base. You can focus using live view with this back, which is pretty well essential for such a shot, as is a tripod. The back has no anti-aliasing filter. In general you don't need one for landscapes although there was one distant building in the scene we shot that exhibited some moiré, which was easily removed/disguised.

Leaf use another of our shots from that test on their guidelines brochure.

I had hoped to be able to do more infrared tests with the Credo during July but, unfortunately, it wasn't possible due to my work load. But the main point is made by the brief trip to the top of Primrose Hill, which is that you can produce dramatic landscapes with this kit. I'd love to see what a real landscape photographer could come up with, given more time and better weather. The Credo WS back is also proving of interest in art conservation and for forensics. There is a lot to be said for the 'shoot first and examine later' ability of very high resolution images.

[My thanks to Leaf and Yair Shahar for their help with this test.]

Inexpensive thermal camera

Your usual thermal imaging camera costs thousands of dollars, often tens of thousands. Now a guy named Andy Rawson in the US has developed (with funding via Kickstarter) a much cheaper device called IR-Blue. It uses your iPhone (or many similar) to connect via Bluetooth to both display the thermal image and superimpose it on a visual image, as the video above will show.

The down side is that IR-Blue has very limited resolution with only 64 'zones' of IR image and those concentrated in a central band. So you won't get a detailed thermal image. That said, it's cheap ($160 kit or $195 assembled) and has real-world applications such as hot-spot-tracing. And for that price it's a fun thing to have ... and it does 'see' in the dark.

[My thanks to open-hardware enthusiast Andrew Back for pointing this out.]

Graphene sensor offers better visible and near-mid IR imaging

A research team in Singapore has developed an imaging sensor made from graphene which promises to have better light-gathering over a wider spectrum and be cheaper then existing sensors such as CMOS and CCD.

A paper in Nature Communications, Broadband high photoresponse from pure monolayer graphene photodetector [abstract], outlines the work although you have to subscribe/pay to access the paper. There is more explanation at phys.org.

A patent is being applied for to cover this technology and the team, led by Assistant Professor Wang Qijie at Nanyang Technological University, will be looking for industrial partners in order to turn this into a commercial product.

This development could lead to cheaper cameras with a range into the mid infrared, which is useful for a range of applications including the reflectography used in art restoration, and the extra sensitivity across its whole response will come in handy as well. A significant achievement ... adding another string to graphene's improbable bow.

Richard Mosse at the Venice Biennale

Richard Mosse's latest work in colour infrared, The Enclave, is opening at the Venice Biennale this week and running until November 24th. I've previously noted his work in the Congo with medium format infrared Aerochrome/Ektachrome. This time it's a multiscreen movie, shot on 16mm and shown in an HD transfer. A 240 page book is being published by Aperture to coincide with the event.

I'm curious as to where he got the 16mm film stock but perhaps it's the Super-16 made for the Wristcutters project but never used.

The venue is the Irish Pavillion, Fondaco Marcello, San Marco 3415 (Calle dei Garzoni), 30124 Venezia which is near the Traghetto San Tomà. Sadly my May culture has been provided by the rebooted Rijksmuseum in Amsterdam and I won't be in Venice. Richard is representing Ireland at the Biennale and there is more on the Ireland at Venice web site.

More Red infrared

Shooting infrared using a Red movie camera seems a popular activity. I've come across another nice example, this time an entry for a Brazilian One Minute Movie competition. The video is from a company called Kipper Tie, based in Surrey (near where I used to live). It's called Infrared Landscapes and was shot on Chobham Common.

I attempted to embed the video but it didn't work ... so just follow this link.

Russia: A World Apart (Simon Marsden and Duncan McLaren)

It's very sad that Simon Marsden's refrigerated and dwindling stock of Kodak HIE outlasted him. He was, to my mind, the finest and most consistent user of that idiosyncratic film stock with its haloed highlights and exaggerated grain. That's not to understate his abilities in the darkroom, but it's the classic HIE look that I will remember him by.

With its distinctive look, many people have thought of infrared film as showing something supernatural. When he loaned us a print of Moydrum Castle for the Infrared 100 exhibition, Simon wrote to me saying ...

The goal of my work has essentially always been the same: to demonstrate that magic is real or that reality is magic. I have used infrared film for its ethereal quality, day is turned into night and nothing in this twilight world is quite as it seems. The unusual texture of the film's grain produces a timeless feature that lies somewhere between an etching and a photograph.

The trail that began with ruined Irish castles has finished with an eerie collection of Russian landscapes in the book Russia: A World Apart. Some are unkempt ruins, which always lend themselves to the increased contrast that infrared brings. I sometimes think that our ruins here in England are too neat: should a derelict monastery be set in manicured grounds? Not all the places visited are ruined: the Winter Palace in St Petersberg is not, but stands under a brooding cloudy sky while the sun fails to break out from behind the Alexander Column. Backlighting is another hallmark of much of Simon's work.

Chernyshev Estate, Yaroplets, Moscow Region

I should not forget the text. Duncan McLaren, who collaborated on those Irish Ruins (indeed he instigated that first project) and a post-USSR venture beyond 'the wall', accompanies the photographs and photographer again. He tells the stories of not only the artefacts' past but often what is happening now; the people he and Simon met on their journey.

Russia: A World Apart is an atmospheric book; in keeping with the best of Simon Marsden's work. Infrared photography is a genre that you either love or just don't get. This book demonstrates one aspect of it at its best.

[Published by Mudds & Stoke at £25 ISBN 978-0-9573795-0-3]

James Jarché

The ITV channel in the UK are repeating the Perspectives documentary where David Suchet "follows in the footsteps of" his grandfather, photographer James Jarché, known as Jimmy. It's on Sunday May 12th at 2215.

Although this documentary doesn't touch on it (but don't let that stop you watching), Jarché was one of the pioneering photographers who, in the 1930s, experimented with the new infrared film and had several of these photos published in the Daily Herald. One of them, showing children watching a cartoon in the cinema in 1934, was included in the Infrared 100 exhibition. He was originally asked by Ilford to document the process of making film, which happens in the dark, and he used Ilford's infrared film for that.

You can see the cinema photo in the National Media Museum/Science and Society collection and Wikipedia have an article about him.

New infrared camera ... at a price

One of the photographs included in the Infrared 100 exhibition was by Carol Highsmith. She's been going round the USA for the Library of Congress with a medium format camera with a digital back and has shot some fantastic infrared images ... and in the digital world medium format means resolutions of 40 megapixels and more. In Carol's case her back had to be converted but Leaf have now announced a wide spectrum medium format back 'out-of-the-box' called the Leaf Credo WS ... for wide spectrum.

Leaf's leaflet (!) [info on their web site] explains that you can use the back to shoot infrared with an infrared-pass filter, normal images with an infrared blocking filter and Infrarcolor with an orange/red filter. (By this I assume they mean the faux colour images we're used to seeing.) The back may also shoot UV but I don't know that for sure as yet and it is very lens dependent. There are two versions with resolutions of 60 and 80 megapixels. 80 megapixels is 10,320 by 7752 pixels.

A wide spectrum camera is great news (although this one will probably set you back over £30 thousand) and a back like this can be used on bodies such as Mamiya (who own Leaf) or technical cameras and Leaf rightly point out that since you don't work with a viewfinder on a technical camera (you use a screen in place of the imaging plane) the built-in hires screen on the back will be very handy.

Thermal imaging role at end of Boston manhunt

The manhunt for the remaining Boston Marathon bomber ended when he was discovered hiding in a boat in a back yard. As this page from NBC's Photo Blog shows, the fugitive's body can clearly be seen even though he was underneath a kind of tarpaulin that was protecting the boat from the weather. There's (over compressed) movie (pity about the commercial) but, further down, a couple of hi-res stills.

A further story explains more about the thermal imaging and, eventually, explodes the myth that you can see outlines of people through walls using far infrared/thermal imaging ... despite what CSI would have us believe. You can however see through thin sheets of plastic, such as a bin liner, at these wavelengths which can not be imaged with a conventional camera.

BBC Natural History infrared shooting tips

I've known Colin Jackson from the BBC Natural History Unit in Bristol for a few years. He has presented his work, filming wildlife at night using near-infrared and thermal cameras, at both the Infrared 100 symposium and at IBC.

I just came across a video from June 2012, tips on infrared filming, on the BBC Academy of Production web site. In it, Colin is shown using what he calls the 'kebab shop camera', a standard definition surveillance camera made by Ikegami. These days he is using a Canon DSLR with its infrared-blocking filter removed which will produce HD resolution images. You should also know that, if memory serves, his infrared lighting is at 920 mn.

What he doesn't talk about in this video is using thermal imaging. There, as you probably know, you don't need lighting as a thermal imager shows the photons generated by the objects themselves.

AP Award for Simon Marsden

I know this isn't a news site but - a trifle belatedly - I can report that Amateur Photographer acknowledged the late Simon Marsden for Exceptional Achievement in Photography in their 2013 awards. I can add that successfully publishing book after book of infrared photographs is an achievement in itself and his contribution to the technique will be (is already being) sorely missed.

As usual, a pointer to the Simon Marsden web site and a note that a new book, Russia: A World Apart by Simon Marsden and Duncan Mclaren, will be published on May 9th 2013.

Infrared on Red

I've noted before the suitability of the Red movie camera for shooting near infrared footage and the suitability of infrared for shooting clouds and a superb example has now been brought to my attention.



This is the work of Glen Ryan and James van der Moezel and as Glen writes,

"... is only a very short section of a much larger project - in scope, duration and resolution (4K) - that I am currently working on with emerging cloud wrangler James van der Moezel."

He promises a six hour uncut version soon.

The Karst formations are near Wee Jasper in New South Wales and the video was part of a recent exhibition called Karst County held at the Belconnen Arts Centre in the Australian Capital Territory (Canberra). Here Glen Ryan's photos and video were exhibited alongside Phil Ryan's acrylic paintings.

The infrared video was shot with a Red camera using 'Nikon glass' and an R72 filter (presumably the Hoya of that ilk).

Watch the video at full HD resolution if you can ... preferably in a darkened room.

Insect infrared reflectance

In the previous post I wrote about the work of Tristán and Michaud in Costa Rica and their papers from the early 1910s on infrared. They were somewhat prolific with their infrared research, including a paper on the appearance of soils, skin and insects over the next few years.

I had been searching for a copy of the article they published in Scientific American on how insects, especially butterflies, look in infrared. Very kindly Michael Mielewczik from the Institut für Agrarwissenschaften (agricultural science) in Zurich sent me not only a scan of the SciAm pages but also a paper he co-wrote on a very similar subject.

Tristan and Michaud had black and white infrared film to work with but Michael and his colleagues have made good use of a digital camera with no infrared blocking and bandwidth-limited to 675-800 nm (deep red/near infrared). The resulting colour palette, presumably due to the optical properties of the beyer filtration on the sensor, is mostly red/magenta. A photograph of a green tree python is particularly striking but the paper really concentrates on insects. Here's an example image showing visible and infrared reflectance characteristics of a group of preserved rose chafer Caelorrhina superba beetles.

The different infrared tones can be clearly seen (B).

The full citation of the paper is:

Mielewczik M, Liebisch F, Walter A, Greven H (2012) Near-Infrared (NIR)-Reflectance in Insects - Phenetic Studies of 181 Species. Entomologie heute 24:183-215

... and you can access the paper as a PDF on the ETH Zurich web site.