More on AVOID remote ash cloud detection

I wrote over a year ago about the AVOID passive-infrared system to remotely detect volcanic ash clouds from aircraft. The system is now being trialled by EasyJet with test flight around Mount Etna in Sicily and the BBC web site has a short film about it.

Two chances to meet Simon Marsden

I guess you're familiar with Simon Marsden's atmospheric (if not downright spooky) infrared photographs of ruins and the like. I've recently mentioned his new book on vampires and there are two chances to get a signed copy and meet the man coming up before the New Year.

The first is at the Walcot Gate, off Walcot Street, Bath, Somerset between Tuesday 29th November and Saturday 3rd December 2011 (11am - 5pm). Like the book, the exhibition is called Vampires - The Twilight World and Simon will be on hand throughout the run to answer questions and sign copies.

A little more formal is a talk called Christmas Spirits, at Stubton Hall, near Newark, Nottinghamshire on Saturday 10th December 2011 from 6.30 pm to midnight. It says here ...

Come and listen to internationally famous photographer, author and ghost hunter Sir Simon Marsden talk about his upbringing in haunted houses that so influenced his career. Illustrated with photographic slides he goes on to describe how he created his singular style and the techniques he uses. But most of all share some of the extraordinary adventures he has experienced when travelling in the UK and in foreign lands in search of the undead, which have sometimes been truly frightening.

Here's hoping his stock of infrared film holds up.

Long-lasting near-infrared emitter

Via various web sites I've been led to a paper published in Nature Materials [abstract].

Zhengwei Pan, associate professor of physics and engineering at the University of Georgia, Franklin College of Arts and Sciences, and his team have developed a material which will fluoresce in a narrow band around 700nm when excited by any visible wavelength including fluorescent lighting. OK, we all know that 700nm is the boundary between red and near-infrared but the eye's sensitivity to that wavelength is so low that we will usually refer to this as near-infrared. You can see the excitation and emission spectra in the Nature abstract.

What is exciting about this work is that, after a short excitation, the material will continue to emit for a long time ... 'seconds to minutes' will result in more than 360 hours output according to the paper. The material can be fabricated into nano-particles which could bind to cancer cells, enabling visual location of small cancers in the body, it can be made into ceramic discs or even paint in order to provide illumination visible only to people using near-IR sensitive devices. I can see an application to detect whether something has been exposed to light recently.

Apparently the starting point is the trivalent chromium ion, a well-known IR emitter when its electrons return to their ground state after excitation by visible light. Usually the effect lasts only a few milliseconds but this new material embeds the chromium in such a way that the emitted light is trapped and releases the energy more slowly. [More info at EurekaAlert for those of us without a Nature subscription.]

This photo shows Zhengwei Pan (left) and postdoctoral researcher Feng Liu in a darkened room, using only their infrared-emitting ceramic discs as a source of illumination. The phosphorescent material was also mixed into the paint that was used to create the University of Georgia logo behind them. You can just see the 'five-o'clock-shadow' on their faces, a result of near-infrared skin penetration. [Credit: Zhengwei Pan/UGA]

Nature in a different light

More innovative thermal imaging from Chris Lavers. His Nature in a different light exhibition is at Paignton Library and Information Centre in Devon until December 6th (not Sundays).

The exhibition combines striking thermal images of endangered species coupled with beautiful conventional photographs of the animals. It is the work of Dr Chris Lavers from Plymouth University, Jean and Ray Wiltshire (regular photographers at Paignton Zoo), and Paignton Zoo’s Dr Amy Plowman, and is funded by the Institute of Physics and the British Science Association Bristol and Bath Branch.

Swords, ploughshares and calendars

Chris Lavers' Swords into Ploughshares Science-Art exhibition is at Topsham Library in Devon until November 7th. The blurb says

His theme looks at transfer of military technologies into civilian applications and provides interesting insights into everyday items: from microwave ovens and the Swiss Army knife to Geostationary satellites!

They should add infrared/thermal imaging of course.

If you're looking for an infrared photography calendar for 2011, since I don't produce one, then you should check out Simon Marsden's Haunted Realm and Poetry of the Dark calendars. More information on his web site www.marsdenarchive.com.

I should also mention that Simon will be giving a talk called The Twilight Hour, and promoting his latest book, at Waterstones in Canterbury next Thursday (November 3rd) at 1830. It costs £3 to see him but that is refunded if you buy the book.

Enquiries: 01227 – 456343 or manager@canterbury.waterstones.co.uk

Free Phil Trans

Great news that the Royal Society has decided to make its archive freely available on line on a permanent basis. This is covered on this web page which also gives a link to the archive search page.

The main journal of interest to us is Phil Trans: the Philosophical Transactions, which started publishing in 1665. Amongst more than eight thousand documents you can find the very papers in which William Hershel described his discovery of infrared:

• Investigation of the Powers of the Prismatic Colours to Heat and Illuminate Objects; With Remarks, That Prove the Different Refrangibility of Radiant Heat. To Which is Added, an Inquiry into the Method of Viewing the Sun Advantageously, with Telescopes of Large Apertures and High Magnifying Powers. Phil. Trans. R. Soc. Lond. 1800 90, 255-283
• Experiments on the Refrangibility of the Invisible Rays of the Sun, Phil. Trans. R. Soc. Lond. 1800 90, 284-292

Herschel was prolific. There are 33 papers of his published in 1800 alone. He was the very model of a major scientific mind.

Phil Trans was freely available during 2010 as this was the Royal Society's anniversary year, and access to the papers was very helpful to me when I worked on my history of infrared photography.

Many people believe that open access to scientific papers, many of which are reporting publicly funded research, is definitely something to encourage. The Royal Society says their decision is part of its 'ongoing commitment to open access in scientific publishing' and I salute that.

Elliott Landy photos in Paris

Another opportunity to see some of Elliott Landy's great photos of 60s musicians, including some stunning colour infrareds and including his Dylan shot.

It's not in a gallery; it's at the Armani shop in Saint Germain des Prés (149 Boulevard Saint-Germain) in Paris. It opens tonight (18th) and runs for a week.

Elliott writes:

Magnum and Armani have created a collection of my '60's Music photos which features some of my abstract and especially colorful imagery - a different group than I normally exhibit - less literal and more painterly. They are printed on a variety of non-paper media in large sizes and have never been printed this way before. Some of the images have never been exhibited prior to this show.

Outer planets ablaze at 1.5 microns

Astronomer Mike Brown at Caltech hunts in the outer reaches of the solar system. He usually concentrates on what is called the Kuiper Belt which extends from the orbit of Neptune out to about twice as far as Neptune's orbit. He recently used the Keck telescope in Hawaii with the intention of imaging Neptune's moon Triton, but the views of the planet itself, and closer neighbour Uranus, were too interesting to ignore. The Keck's adaptive optics system, which compensates for turbulence in the earth's atmosphere, produces stunning results.

Neptune, glowing like a demonic cricket ball, shows the two distinct bands which are glowing at the imaging wavelength of 1.5 microns (1500 nm). Of course these are not really 'hot' since the surface of Neptune is -200 C and the bright bands will only be a few degrees warmer. These correspond to faint but visible features on Neptune's 'surface'.

With Uranus the main features are the rings, which stand out distinctly given the low level of radiation from the planet itself, and the spot to the top left which is the moon Miranda. The bright spots on the surface are clouds. This is notable because the 'surface' of Uranus, in visible light, is almost devoid of any features (although, as the 'northern' uranian hemisphere warms up some banding is appearing).

There is more at space.com.

RW Wood took infrared photographs of gas giants Jupiter and Saturn at the end of October 1915. He had been granted use of the 60 inch reflector at Mount Wilson and took photographs through infrared, yellow, violet and ultraviolet filters. His infrared filter had a band-pass of 700 nm, with its upper limit being determined by the plate sensitivity, which was probably less than 800 nm. In this case infrared photographs showed fewer features than visible light whereas belts were clearly shown on the violet and ultraviolet plates. (It is not possible to record a wavelength as long as 1.5 microns using photographic emulsion, so an electronic sensor has to be used, although this is not thermal imaging. However, this wavelength is still within an atmospheric window for infrared.)

You can read Wood's 1916 paper on the SAO/NASA Astrophysics Data System (ADS). It is entitled Monochromatic Photography of Jupiter and Saturn.

[My thanks to Mike Brown for permission to reproduce his images here.]

Infrared invisibility cloak

RV Jones, in his excellent book on British scientific intelligence during the Second World War, called Most Secret War, tells the story of a German attempt to camouflage submarines so that they blended into the sea at both visible and far-infrared/thermal wavelengths. They developed a painting scheme which combined a black undercoat with a top layer of varnish that included powdered glass in suspension. To the naked eye the boat would look grey, presumably like the grey north Atlantic, but to an infrared viewer it would look dark, again like the sea. The properties of the undercoat, glass and varnish were such that infrared passed straight through and was absorbed by the undercoat while visible light was refracted by the glass and gave a grey appearance.

This was a neat trick, of which Jones was most complimentary in his book. Unfortunately the British were actually detecting submarines by using radar and not infrared.

This story comes to mind when seeing the news stories circulating about a thermal invisibility cloak called ADAPTIV produced by BAE systems (their press release). The plan is to enable a military object, such as a tank, to either blend into the background or to appear to be something innocuous. This is done by covering an appropriate surface or two with ingenious hexagonal panels that can be electronically set to give off suitable far-infrared radiation on demand. The trick being the ability to change temperature very rapidly and to adopt a temperature that can be lower as well as higher than ambient.

A thermal imaging camera can be used to pickup what is behind the object and use the ADAPTIV panels to show this on the opposite surface, thus rendering the object invisible. By replacing some of the output pixels with a different thermal pattern the object can be made to appear smaller and different. It's unclear whether such as system could yet be used by an individual soldier but objects larger than vehicles ... even buildings ... can be cloaked using this technology.

The promotional video [now no longer online] is rather fun, not only because of the 'so natural that you want to go to war' music but also for the shots of ADAPTIV in action. I particularly like how the panels can be used to display advertisements!

Infrared Polaroid

A box of Polaroid Land Infrared Film turned up on eBay a few months ago. I wasn't aware that such a thing existed but there it was, and the seller kindly included photographs of the packaging and the data sheet.

The film was reportedly available between 1964 and 1969 (the data sheet shown was dated May 1967) and was designated Type 413. It was a black and white film sensitive between UV and just beyond 900 nm with a peak at 830 and a trough at 510. Equivalent ASA rating was 200 with a Wratten #87 rising to 600 with a red filter and 800 with no filter.

If anyone knows of any examples taken with this film please let me know.

Simon Marsen's Vampires

You are probably aware of Simon Marsden's atmospheric infrared photographs of ruins and other settings with a supernatural ambience. He uses Kodak HIE infrared film, with its characteristic grain and halation, and usually photographs with strong back-light to increase the day-for-night effect.

Simon has just circulated an email about his next book, due to be published in the UK and USA in October, entitled Vampires: The Twilight World and published by Palazzo Editions. I have to say the cover is stunning, and Whitby Abbey is one of those places of which I've always wanted to take an infrared photograph.

Signed copies will be available (signed by Simon I should add ... in case you've been watching too much Twilight) from Simon Marsden’s website from 1st October 2011: www.simonmarsden.co.uk.

Soviet infrared photography

There is one gap the history of infrared photography of which I have been very conscious: the old Soviet Union. The soviets obviously had infrared film, the movie Soy Cuba made in the early 1960s made extensive use of it, and I found a NASA reference to some colour infrared film being flown on the space station.

Of course, my not reading Russian doesn't help but I have managed to track down an intriguing publication from the American military which is available to buy from the National Technical Information Service. It's a translation of a book by I B Levitin published in 1961, translated in 1967, and titled Photography by Infrared Light (approximately).

The document is described, rather oddly, as a machine translation, which has then been 'tidied up' by a human. Actually it reads quite well. The term used for the film is infrachromatic, though I don't know whether that is a literal translation: but it's a nice term.

According to the book, at that point there were three film types regularly manufactured in the USSR - Infrachrom 760, Infrachrom 840 and Infrachrom 880 - with a 720 version manufactured 'irregularly'. These were made in sheets, 35mm and 'wide film' of 19 and 33 cm width. I did a double-take over that: 33 cm is over a foot! The author notes that the number usually refers to the point of maximum sensitivity.

Agfa in East Germany also made infrared film. Eleven different types are listed, divided into khart (less sensitive more contrast) and rapid (more sensitive less contrast). [The translator notes these names are transliterated from Russian rather than being the German terms.]

The book then goes on to list foreign film types, and this list contains more types than I was aware of so I will list the manufacturers here (as shown in the document):

• Eastman Kodak (USA)
• Ferrania (Italy)
• Gevaert (Belgium)
• Guilminot (France)
• Kodak (Great Britain)
• Kodak-Pate (France)
• Konishiroku (Japan)

Pate is presumably Pathé and Konishiroku Honten was the name for Konica until 1987 (see Wikipedia entry). So the Konica film was older than I realised, by a long way, and it seems Kodak in the UK made film separately from the USA at the time. Of course by the end of its life Kodak's HIE film was only made in Rochester.

Levitin's book is very technical and delves even deeper into the physics and chemistry than Clark. It perhaps deserves a wider distribution but for the moment, if you're interested, you can buy it from NTIS as document number AD663365. NTIS is worth a search anyway, for example it tells us that astronaut Gordon Cooper took infrared photos from orbit on May 16, 1963 during Mercury Spaceflight MA-9 (Faith 7). Of course, now I know about this, a Google search yields several results, explaining that his infrared shots were for meteorological purposes. What I don't know is whether these were the first infrared photographs from space ... I'll have to find out.

Clouds

Lake Pemichangan

It's clouds' illusions I recall ... says the song. Since infrared photography is perfect for delineating clouds against a black sky I thought this slideshow on the BBC web site would provide a useful guide. So next time you will know what those clouds are called. It's a pity there are no infrared shots ... so I've included one of my own here.

Kenji Hirasawa's Celebrity: more thermal art

I've mentioned thermal imaging exhibitions by Joseph Giacomin and Chris Lavers in the past. During July there is an exhibition of thermography by Kenji Hirasawa at the KK Outlet in Hoxton Square, London, called Celebrity. He's used a thermal camera to look at people in Madame Tussaud's, the wax models being almost invisible to the termal eye so that the 'hot' people seem to be interacting with empty space.

You can see more via the KK web site and there will be a book as well. There are other thermographs on Hirasawa's web site and I am particularly taken by some portraits. I have to say that I am becoming bored with the standard orange-red palette being used with pretty-well all the thermographs I'm seeing but since thermal images are always monochromatic (they show the temperature for each pixel), there isn't another 'dimension' to provide a mechanism for more varied colouration.

Celebrity runs every day except Sunday until July 30th.

In the meantime, Thermal by Joseph Giacomin is available through Amazon.

Infrared can switch off your camera

You probably know that all digital sensors are sensitive to near-infrared and that most cameras block out infrared to avoid contaminating the colours. I found that my iPhone camera is indeed sensitive to IR and could clearly see the infrared emitters from a headphone loop system at a conference I recently attended.

I had wondered many years ago whether flooding a cinema screen with infrared could hamper anyone wanting to film the movie from the screen. Back in the days of poor filtering this may well have worked but I suspect filtering would remove the infrared with modern cameras.

Apple have applied for a patent for a mechanism that carries a code in an infrared signal 'broadcast' at a venue, decoding it in the phone (or other device) and using the result to determine whether the camera should be deactivated. This is a similar idea to the coding that prevents scanners and photocopiers from copying banknotes. The BBC carried a story reporting that rapper Tinie Tempah was against this idea because he likes his fans to video his concerts (a bit like the Grateful Dead for those of us a little older ... the Dead used to set aside an area in front of the stage for fans who wanted to record their concerts). Apple's system would be optional: it would be up the venue/performer to use it to disable cameras.

Some of the artists interviewed by the BBC had a simple view. They didn't mind being videoed but they thought their fans should actually be enjoying the concert instead.

Of course Apple could configure the iPhones to receive those headphone loops (usually helpful to people with impaired hearing). That would be nice: you could use your own headphones.

Infrared: the eleventh dimension

A slightly whimsical post this time.

I've been thinking about the multi-dimensional nature of photography and how choosing the wavelengths in which to shoot is part of a photographer's wider set of choices when taking a photograph: the dimensions.

We have ...

1. the three dimensions of space for our position
2. the three dimensions of orientation for our direction of shooting (pitch, roll and yaw)
3. the dimension of perspective and framing (choice of focal length)
4. the dimension of time (when we press the shutter)
5. the dimension of duration (how long is the exposure)
6. the dimension of focus (and depth of field)
7. the dimension of spectrum (what wavelengths we record)

By that reckoning choosing to look at the world in infrared is part of the eleventh dimension of photography. If that works then there is an eerie similarity with part of string theory which postulates that space-time has eleven dimensions, of which we only experience three.

CEK Mees biography

Browsing through Google Books I came across a good biography of CEK Mees, written by Walter Clark, from New Scientist, published in 1979. We forget that, as part of his long and distinguished career at Kodak, Clark set up Kodak's Harrow labs in 1928 and stayed there as director of research until 1931.

This is the link to the article.

The Science and Art of Thermal Imagery

I've mentioned Chris Lavers' thermal images before. His next exhibition is at Teignmouth Community College (in Teignbridge, Devon) and is called The Science and Art of Thermal Imagery.

It runs from 1200 on Thursday June 16th until 1100 on Tuesday July 5th and this is how Chris describes it:

This exhibition provides an introduction to the topic of thermal imagery, with particular focus on the science that can be provided by wildlife thermography, and the aesthetic art of both natural and man-made objects, including iconic art. This exhibition is based on the 2008 and 2010 Institute of Physics sponsored Nature in a Different Light exhibitions.

Richard Mosse and Aerochrome

I was away for a couple of days so it was only today (Monday) when I opened the Guardian newspaper Saturday magazine to find some interesting colour infrared photographs taken in the Congo by Richard Mosse. It's a (probably) unique application of infrared photography to reportage. He was unaware of it but he was taking these photographs almost exactly a century after the first infrared photograph was published early last year.

The best place to explore the photographs is his web site (natch) where you follow links either to the project itself (called Infra) or to the text/press page.

He's interested in the aesthetic of the false-colour images, having seen it on a Grateful Dead album cover (and elsewhere ... more on IR rock photos here). The idea is to make us take a second look at things when using this film. It's very difficult to get good results with the film for a whole bunch of reasons, and I am impressed technically with what Mosse has achieved. Partly this is because he worked in medium format, using stock cut down from the 70mm Aerochrome rolls, which provides a sharpness the 35mm Ektachrome rarely achieved.

The stock, KODAK AEROCHROME III Infrared Film 1443, is now discontinued, which would make it the last mainstream infrared film. Apart from some obscure Soviet Russian film, Kodak seem to have been the only company to experiment with infrared and colour-shifting. In case you are unaware, Infrared Ektachrome and Aerochrome (essentially the same film) have three sensitive layers, one each for near infrared, red and green although all layers are sensitive to blue which must be filtered out. A yellow (minus-blue) filter was the 'correct' filter to use with this but may people also used orange and other filters to play with the resulting palette of colours. The dyes in the film were coupled in such a way that infrared in the original scene was rendered as red, red as green and green as blue.

It was originally produced as camouflage detection film. The first incarnation appeared in 1942 in the form of 'Aero Kodacolor Reversal Film, Camouflage Detection'. The idea of combining infrared and panchromatic emulsions with colour processing (to produce a false colour result) had originated in Kodak's laboratory in the UK in 1941. The plan was to have two layers which were sensitive each side of 700 nm, where the Wood effect kicked in. Early tests of the new film, used in conjunction with conventional colour film, were positive although the film was considered to be too slow. By 1945, a faster version of the film had been standardised and was recommended for operational use in the Pacific at the close of the second world war.

Eventually, the film became widely used to remotely detect the health of foliage, even from space. Since healthy foliage reflects a lot of near infrared (due to the Wood Effect) the relative amounts of green and infrared that a plant reflects are an indicator of its health. With this infrared film the colour shifts from magenta to red as the foliage gets healthier. Camouflage detection is a subset of this since green paint and dead leaves could easily be distinguished from the real thing. That's until the 'enemy' started making special infrared camouflage paint.

So one thing that strikes me about Richard Mosse's photos from Congo are how magenta the landscape is: stressed as the botanists would say. Healthy foliage would be bright red but there is little of this to be seen, although there is some.

According to an interview in the BJP, which is reprinted in the text/press page of Mosse's web site, he's going to experiment with infrared movies, shot with a Red One without its infrared blocking filter. This can be easily done, as I discussed this very process with Red at IBC about four years ago. There may be issues with any colour-splitting filters in the light path (splitting RG and B to the three sensors) since the dyes in the filters will have their own variable amounts of infrared response. Richard says that "It will be a kind of blown-out monochrome palette", apparently expecting it to look like a night scope. I would expect it to look more like the usual output of a DSLR with an infrared filter in front of it but those pesky colour-splitting filters are a bit of a wild card. I did an experiment with Ikegami for last years' IBC and while the monochrome infrared output was poor (because of the splitter filters) we did get a good result using a minus-blue filter. I've written about this approach before, when I went to the BBC Natural History Unit and we tried a minus-blue filter on a modified DSLR to emulate infrared Ektachrome.

So it may be that, with a bit of suitable channel mixing, Richard Mosse's infrared movies will continue the look of his aerochrome stills. I hope we'll see the results.

RW Wood at the Royal Institution

On May 19th 1911, Professor RW Wood presented one of the Royal Institution's legendary Friday night discourses with the title Recent Experiments with Invisible Light. This built upon the paper he had presented the previous September to the Royal Photographic Society and took place almost at the end of his 1910-11 sabbatical in Europe.

The discourses, which continue to this day, are formal affairs, as Wood reported to his biographer ...

His Grace, the Duke of Northumberland, not being available at the time, Gertrude [Mrs Wood] entered the hall on the arm of the Right Honorable Earl Cathcart, Vice-President, followed by my daughter Margaret, on the arm of the diminutive Sir William Crookes, who came nearly up to her shoulder and whose long white mustache, waxed at the ends into two sharp spikes, fascinated her. I brought up the rear. There was a brief introduction and at last I was standing behind the famous lecture table, giving my talk...

The following Friday, Wood was still in London and attended the discourse given by Marconi who was proposing to demonstrate reception of a radio transmission live across the Atlantic from Nova Scotia (a feat many still thought impossible) using an aerial flown using kites and, as Wood reported, "such a display of impressive modern electrical appliances as one seldom sees outside a World's Fair." Marconi's presentation, according to Wood, was rather monotonous. He read from a manuscript with his elbow on the desk and his head in his hand. "He appeared to be the least interested person in the auditorium ... and there were no experiments." Marconi droned on and his assistants became more and more agitated. The wind was dropping and while the morse signal from Canada was audible it would not be for long.

Despite Wood's encouragement the assistants would not dare to interrupt Marconi. So finally, when he eventually announced "We shall now listen to the signals coming across the Atlantic" the assistants could only shake their heads: the wind had dropped, the kites were down, the signal was lost.

A little tangential to infrared imaging I know, but it's salutary to remember just how much has changed in 100 years.

[With thanks to Doctor Wood: Modern Wizard of the Laboratory (1941) by William Seabrook]

Tristán and Michaud

In a letter to the Times, dated June 4th 1932, CEK Mees referred to long-distance infrared photographs of mountains, taken in Costa Rica in 1915 or 16 by Gustave Michaud and J Fidel Tristán of Costa Rica State College, which were published in Scientific American. I've been trying to track down more information about them, and it seems they were pioneers in both infrared and ultraviolet photography.

Unfortunately I have been unable to find the Scientific American article to which Mees refers. Scanning through the bound volumes for 1915 and 1916 in the British Library did not reveal them. However I did find a few relevant items there and on the web.

They wrote an article on Flowers photographed by invisible light in the October 10th 1914 edition of Scientific American. Most of this demonstrated how many white flowers came out 'black' when photographed under ultraviolet light, or showed some patterning that was not apparent in ordinary light. They did comment on how flowers looked in infrared but as they usually showed up as 'white' they didn't find this as interesting.

I have photographed flowers, even dark ones, in infrared. This is an example. It is actually a dark red rose, illuminated by a flash gun.

An unusual reference to their work appears online in a 1918 edition of a magazine called Rays from the True Cross (see page 209) in an article called Insects that see 'Invisible' Light, which tells us that in an edition of Scientific American dated Jan 15 they were again investigating the appearance of flowers, which

led us recently to photograph, in ultra-violet and infra-red lights, a number of butterflies

This article was not in any Scientific American in 1915 but the date may well refer to January 15th, possibly in 1918 ... but I have not had a chance to track that down as yet.

A further piece of research was published in Archives des sciences, March 1915 into absorption of UV and IR by arable soil and included both kinds of photographs.

It is remarkable that only a few years after Wood demonstrated that the world could look different in infrared (and UV) that these two researchers used photography to investigate aspects of this in detail. I would like to find out more about these two. Anyone know anything more?

[FYI: A useful resource of Scientific American for this period can be found at www.scientificamericanpast.com.]

Olaf Bloch's 1930s lectures

In the early 1930s Olaf Bloch was the president of the RPS. He was also chief chemist of Ilford's laboratory, and I was already aware of a paper he presented early in 1933 to the Royal Society of Arts called Recent Developments in Infra-red Photography. During that presentation he took an infrared photograph of the audience which was projected later. The RSA journal does not include the photograph.

I recently got hold of a copy of the RPS Photographic Journal for August 1932, knowing it included an article on infrared. I had hoped that, given the date, it would give me some more information on the infrared plates that became available during 1932 from Kodak and Ilford. That wasn't the case. Instead the RPS paper was an earlier appearance of Bloch's presentation, actually given in April 1932 and hence a little early for my historic purpose.

However, despite this lecture being given unexpectedly because the planned showing of various new pieces of equipment wasn't possible, Bloch performed his 'party piece' with an infrared photograph of the audience. This is it.

I don't think this was taken in complete darkness but I would expect the normal room illumination was low and lamps with infrared filters were set up for the purpose. The published paper also included a long-distance infrared photo of the Isle of Arran that was published in the Times on May 30th 1932.

Is there or is there not an infrared Olympus Pen?

Further to my note about a infrared version of the Olympus EP1 being seen at a show, we have tried to get some further information from Olympus about this and, sadly, we got nowhere. This probably means that yes, there is one ... but there is only one and it's not a product.

You can guess my feelings about manufacturers missing a trick with the potential market for well-configured infrared cameras.

Further back on the Wood Effect

In a post in December last year I wrote about the Wood Effect, which causes foliage to look white in infrared photographs. I had traced the term back to a reference to an article in a journal called Photofreund published in Germany in 1938, which I had not seen.

Now, with help from a friend in Germany, I have been able to read the article. (Bearing in mind I don't speak German so this was achieved with some assistance.)

The paper is called Warum erscheint gruner Pflanzenwuchs bei Infrarot-Aufnamed weiss? This translates as Why do green plants appear white on infrared-photography? and one paragraph (translated) reads

In that kind of pictures it is extremely disturbing when all plants appear in an unnatural bright tone, as if covered with white frost or snow. Where does this so-called "Wood-effect" (1910) come from?

This doesn't actually resolve my search, since Dr Marmet, the author, refers to the Wood Effekt as bezeichnete, literally designated according to my dictionary. This implies that the term was already in use and Dr Marmet had heard it elsewhere, but whether in a German or an English language publication is unclear. He includes the 1910 date as well but doesn't say to what he refers: this could be the RPS Journal or Century Magazine. Remember that Mecke and Baldwin, writing in 1937, were calling it the Chlorophylleffekt.

The difficulty with online searches for wood effect is that you keep coming back to timber! But I shall keep digging.

Infrared 100 Exhibition photographs online

For those of you who were unable to get to Bath for the Infrared 100 exhibition last October, the RPS have put some of the images online on their web site.

Go to www.rps.org/fenton-house/Infrared-100 and you can browse through some of the historic and contemporary photographs we included. These include a couple of RW Wood's photos from 1910 and 1911, Abe Frajndlich's Rosebud as Demeter, Carol Highsmith's Streetcar on St Charles and Teresa Airey's Magical Banyans. Professor Francis Ring's 1959 thermal image of an arthritic knee, made with a prototype scanner using a searchlight mirror and bicycle chains, and Professor Robert Greenler's 1971 photograph of the infrared component of a rainbow are also included.

A selection of images are also featured in the current RPS Journal.

Thermal Street View from MIT

The aim may be to provide a rapid energy audit of buildings but MIT have a thermal imaging system that is interesting for purely visual reasons.

The full story is in this news piece on their web site, complete with video.

Here's what caught my eye ...

The new process begins by photographing buildings with a system the team developed to get high-resolution, long wave infrared images using an inexpensive, low-resolution camera. Normally, the cost of high-resolution far-infrared cameras is prohibitive for such widespread use — such cameras can cost $40,000 each. As a substitute, the team developed a novel patent-pending technology called “Kinetic Super Resolution” that uses a computer to combine many different images taken with an inexpensive low-resolution IR camera (costing less than $1,000), that produces a high-resolution mosaic image.

Note that in this context 'high resolution' would be 640 by 480 pixels resolution for $40K. In this case the MIT system's Kinetic Super Resolution improves image resolution by using moving (presumably this means scanning) images. I would imagine that this is trading temporal resolution for spatial resolution by looking at how successive pixels differ when these pixels are displaced by less than pixel/image resolution. A patent is pending.

DNS tidy-up

I have, at last, sorted out the domain name for this blog so it runs properly off www.infrared100.org ... although infrared100.blogspot.com still works. Apologies if you got a seemingly spurious landing page while I sorted out the routing.

Evaporography - home brew thermal imaging

There are a few indirect methods for imaging far-infrared radiation, relying on a visible effect caused by the infrared which can then be seen or photographed. One of these is known as evaporography.

Dr Marianus Czerny from the University of Frankfurt, writing in Zeitschrift fur Physik in 1929 (this is a big file of translated papers ... go to page 1), proposed coating a celluloid membrane with a thin layer of white napthalene and putting this in an enclosure saturated with napthalene vapour. Any areas of the coating that heated up due to infrared radiation falling on it would evaporate (sublime) and it would be possible to photograph the membrane to 'fix' a record of the patterns produced. This became known as an evaporograph.

This technique was largely unknown to the public until May 1956, when a newly-declassified device called Eva was demonstrated by Baird Associates of Cambridge Mass. The images were unmistakably thermal images and, in this case, were formed on a thin sheet of plastic coated with silicon oil. This was held in a small vacuum chamber with a salt window through which the infrared passed. The thickness of the oil film varied with the amount of radiation falling on it and interference effects resulted in this being shown as different colours with a resolution of one degree (presumably Fahrenheit). Baird's evaporographs (or sometimes evapographs) appeared in several magazines, including Time, Popular Science, Popular Mechanics and Life.

Although Baird's applications, at least as promoted, were of thermal imaging, the evaporograph principle can be applied to shorter wavelengths. Pol F Swings, who wrote a paper in 1945 on astronomical applications of evaporography, compared this to near infrared photography using Agfa 1050 plates (without ammonia hypersensitisation) and concluded that at wavelengths shorter than 1200 nm the Agfa was faster where as at wavelengths longer than 1300 the evaporograph was faster.

The process is relatively easy to reproduce, probably well within the range of a school laboratory, and a recipe currently available on the internet (scan down the page), but dating from 1972, claims to be able to record the heat from a human body after dark in ten seconds.

Infrared London at the Strand Gallery

A quick mention for an exhibition of photographs by Quentin Bell, which is running at the Strand Gallery (32 John Adam Street, London WC2N 6BP) from February 15th to 26th. It's a retrospective called A Line in the Sand and includes some infrared images from a project shot around Greater London.

Bell was commissioned by the owners of the May Fair Hotel in London to produce 105 images of London for their guest floors. You can see these on his web site. It's a nice collection, including some of my old haunts out west. The infrared artefacts are subtle: the images rely more on the textures of the film than infrared effects but you do see the occasional Wood effect creeping in.

I don't know how many of the shots will be in the exhibition, but you can always go and stay at the May Fair and see them all!

Is DARPA the future of thermal imaging?

Last week DARPA ... you know ... the people who invented the internet ... published a 'funding opportunity' called Broad Agency Announcement: Low Cost Thermal Imager Manufacturing

It's got this snappy URL for access to the PDF:

www.fbo.gov/utils/view?id=b332544b1b6c59a8f94eed3413e842c0

Basically they want manufacturers to come up with thermal imaging devices that can be used by 'warfighters' in much the same way most of them now use image intensifiers. They want it small, such as to work in or with a smart phone or PDA, low cost, evolutionary rather than evolutionary (no chance for the micro-yagi imager idea then) and to work in the 8-12 micron band. This was described to me by a contact at NASA as the place 'where bodies glow best'.

There's a good analysis of this story in the Register but even more interesting is the idea that this kind of thermal imager could be combined in a broad-spectrum augmented reality display which, eventually, we all could wear. These could be glasses or even contact lenses and could allow us, or an intelligent system working on our behalf, to show us a range of views of the world ranging from the visible we already see, through image intensifiers and near-infrared to thermal. Great for hill-walking or even driving at night.

If DARPA achieve their goal (which isn't certain of course) then this could be coming to a headset near you within a few years ... because DARPA want this to cost less that $500, be lighter than 25 grams and say "If successful, the IR cell phone camera-like approach will lead to widespread proliferation in military and consumer products."

I can't wait.

Olympus Infrared EP1 seen at PDN PhotoPlus

This is a story that needs more research. The Phoblogger saw a specially-modified version of the Olympus EP1 at PDN PhotoPlus Expo 2010 in November. It is apparently being modified by another company but would appear to have Olympus's blessing.

This is a 'Pen' camera with 12 megapixel resolution. It has live view and since the same sensor is used for imaging, focussing and exposure, it should work well for IR.