Monday, 27 July 2020

Weegee and Kubrick: The infrared connection

I have recently been reading Christopher Bonanos' biography of the famous New York photographer Weegee. Weegee's reputation grew in the 1930s as a news photographer covering mostly crime and fires at night. He soon developed a style that transcended standard news pics partly due to his innate sense of a good image, but also his shots of the reaction to events, as much as the events themselves.

One item in Weegee's armoury, besides his police radio and pocketfuls of flashbulbs, was infrared. He picked up on it in the early 1940s, a few years after it become available from companies like Kodak through regular retail channels. Before the mid 1930s, if you wanted to take infrared photographs you had to sensitise the plates (for it was plates) yourself. Now there were plates with a sensitivity beyond 700nm which could survive being retailed and being carried around by a busy photographer.

Bonanos places Weege's first use of IR for publication in April 1942, shooting during a wartime blackout drill. He returned to the medium "again and again" using the phrase "Made with invisible light" and many of his most recognisable shots were made this way. He shot audiences in cinemas, the opera and even a circus. Sometimes by rigging IR flood lights or more often by using flash with special IR-pass coated flash bulbs.

My favourite, entitled Opening Night at the Met was taken on December 3rd 1944 and shows a small group in the audience, including a priest and a lady with opera glasses. Behind them stand two women and a man. He is displaying classic IR 'five o'clock shadow' (caused by IR penetrating the skin slightly ... he was probably clean shaven) and one woman shows another feature of the infrared look, which makes eyes look like dark pools. This may well be Kodak film but it shows little of the usual IR film look with halation. This is simply because it would have been a half-plate negative: the effects are there but more subtle than we got with 35mm film.

I can't directly show you the image but I can link you to it on the Getty site. It's a gem: Opening Night at the Met. They're watching Faust by the way.

Getty have 84 more examples of Weegee's infrared photography. This search will get you there. Alternatively, there are 43 shots online at the International Centre for Photography, where Weegee's archive is held. These include some of him with his infrared kit, ready to shoot, and even disguised as an ice cream seller.

Via the Bonanos book I discovered that not only was Stanley Kubrick an admirer of Weegee (his "last great set of photographs" was shot during the filming of Dr Strangelove) but Kubrick used infrared several time during his earlier career as a photographer. Some examples of his work for Look magazine can be found online, although it's unclear how many were actually published. One striking shot, very reminiscent of Weegee's work, is from a set Kubrick shot for Look in a set titled "Park Benches-Love is Everywhere," from 1946. In it, a young couple are seen disturbed in mid-kiss on a fire escape, looking up at the camera. It has the classic characteristics of an infrared portrait, with dark-pool eyes, and the light pattern tells us it was shot with flash.

You can find the fire-escape photo, along with other Kubrick stills work, in this review of a retrospective exhibition in 2018 called Through a Different Lens: Stanley Kubrick’s Photographs.

There's some interesting information on infrared flash in a blog post by social documentary photographer Daniel D. Teoli Jr, including the kind of bulbs used by Weegee. In case you're wondering, electronic flash guns do give off infrared, so you can filter them for candid photography. Usually, no-one will see the flash unless they are looking at the gun, in which case they'd maybe see a brief dull red light. This would be partly due to the very low sensitivity of our eyes to very deep red going on infrared (0.01% of our green sensitivity at 750 nm according to Allen's astrophysical quantities) and to the tiny amount of deep red that the filter lets through.

Christopher Bonanos' biography of Weegee is called Flash: the Making of Weegee the Famous and is published by Henry Holt. It's a very readable account not only of the man's eccentric life but also, in passing, builds a picture of what it was like as a jobbing news photographer on a crime beat in New York between the 1930s and 1940s in New York. And I am cited twice in the notes.

Sunday, 10 May 2020

Lucky Infrared Images of Jupiter

Back in 2011 I noted some IR shots of outer planets by Mike Brown at Caltech, at a wavelength of 1.5 µm.

Last week another fascinating set of images, this time of Jupiter, emerged. These were at 4.7 µm and rather than a demonic cricket ball this time the infrared image resembled a jack-o'lantern.


This wavelength reveals a glow from relatively warm deeper layers of the atmosphere breaking through upper cloud layers. In visible light this is obscured by even higher haze in the atmosphere. The image here is a composite built from a number of so-called 'lucky' images, captured from earth during brief pauses in our atmospheric turbulence. The instrument was the Gemini North telescope on Hawaii’s Maunakea volcano, at an altitude a little over 4,200 metres.

To find out more, I'll point you at the paper available on the Gemini Observatory web site.

[Image credit: International Gemini Observatory/NOIRLab/NSF/AURA M.H. Wong (UC Berkeley) and team Acknowledgments: Mahdi Zamani.]

Wednesday, 4 March 2020

Flying high ... for infrared

One of Nasa's longer-running infrared astronomy projects is the Stratospheric Observatory for Infrared Astronomy (SOFIA). It uses a pre-loved 747 with a suitable new aperture to fly high and catch infrared radiation from above 99% of atmospheric water vapour.

Not quite flying your Lear Jet to Nova Scotia for a total eclipse of the sun but still pretty cool.

Read about it on the Scientific American blog.

Tuesday, 11 February 2020

Spitzer gone ... waiting for Webb

I have to admit that I am not as au fait with what's happening in astronomy these days as I should be; especially since infrared astronomy, once the new kid on the block, is where most of the action now occurs.

The end of January saw the decommissioning of NASA's Spitzer Space Telescope. At about 1430 PDT on Thursday January 30th, JPL reported ...

...the spacecraft was placed in safe mode, ceasing all science operations. After the decommissioning was confirmed, Spitzer Project Manager Joseph Hunt declared the mission had officially ended.

We now have to wait until March next year for the James Webb telescope to launch and the next phase will begin.

NASA's Spitzer Space Telescope Ends Mission of Astronomical Discovery

Thursday, 16 January 2020

Filtering a full-spectrum camera

My full-spectrum camera, a FujiFilm IS-Pro, has no built-in filter and shoots from near UV to near IR unimpeded. This also means that when I put a filter over the lens it also affects what I see through the viewfinder. With, say, a 720nm filter I am unable to see through the viewfinder so would have to use a tripod. Sadly the Fuji's live-view is pretty-well useless.

Many people replace the high-pass IR-blocking filter over the sensor with a low-pass filter such as a 720 or 820 nm to get around this problem ... at the small expense of loss of versatility.

In recent years I have used a deep blue filter, which I can see through to frame. Blue filters usually pass a lot of near IR. You can use a red filter of course, as you might have done with film, but I find the blue filter sometimes produces an interesting colour balance with minimal post-processing. Interestingly, the auto-focus works most of the time, which helps.

I recently bought a specially-designed filter for a type of colour infrared photography from the American company, Kolari Vision. It's called their IR Chrome Lens Filter, which I'll come back to in a moment. This nudged me into looking at results of a number of filters with the full-spectrum camera.

First, here is the camera output without any filter. This is basically a 'normal' colour image but with infrared contamination. You can click on the images to make them larger.


Next is a minus-blue (ie yellow) filter. This can be used to emulate the old infrared Ektachrome film ... see this blog page for more details.


Next comes the red (#25) filter.


Now the blue filter. Different black and white results can be achieved by either removing saturation or by selecting individual channels. (This also applies with other filters of course.) The green channel is useful because, with a Beyer filter camera the green channel has twice as many pixels as the red or blue. With this filter I find I need to under expose (according to the camera) by 3 or 4 stops.


This is Kolari's IR Chrome Lens Filter, which gives a good approximation of the old Ektachrome images. However, it is not exactly the same so is not as useful for foliage health analysis: but it's not a bad approximation.


I had achieved good results using neutral density filters in the past, with Sony's Night Shot, since the ND doesn't apply at IR wavelengths. So I bought a variable ND filter, which is basically two polarising filters together. You rotate one with respect to the other in order to reduce the amount of visible light going through. In this case once I had frames with minimal density I simply rotated the outer filter until I could only just see anything then fired the shutter. Autofocus worked and by trial and error found the exposure change: in this case under by 4 stops. There is a little (false) colour information left but this method works best for a monochrome result.


Finally, for comparison, here is a 720 nm filter result.


One thing this experiment also showed me was how bad the chromatic aberrations are around the edges in the lens I am using, which are quite noticeable with colour shots but usually vanish when reducing to monochrome.

For more on this subject, here is Kolari's page outlining the characteristics of their various filters.