Thursday 8 February 2024

Uranus is not as boring as we thought

The conventional view of Uranus has been that its apparent surface shows few, if any, distinguishing features. The images from the Voyager 2 probe in the 1980s showed what Nasa describes as a "placid, solid blue ball".

The James Webb telescope, using infrared wavelengths rather than Voyager's visible ones, shows something else. In this light the north polar ice cap becomes visible. (Uranus, bizarrely, rotates almost at right angles to all the other planets so the north pole is, in this configuration, pointing towards us.) Some storm clouds are apparent as well, and the planet's rings show up clearly.

I've not been adding to this blog of late, so I realise I am a bit late with this as a group of photos were released by Nasa back in December 2023. The Nasa web page has copious information about the set, which includes wider field photographs (also larger than the image above).

That Nasa page doesn't give information about the wavelengths used for the image. There's a more detailed report from Scientific American, which notes that image is built using wavelengths of 1.4, 2.1, 3.0 and 4.6 microns. Since photographically, we're more used to nanometres this means 1400, 2100, 3000 and 4600 nm.

[Image credit: NASA, ESA, CSA, STScI]

Monday 14 August 2023

Thermal images of sun-baked Phoenix Arizona

The Guardian recently published a photo set matching far infrared images of Phoenix with ordinary photographs.

The images were taken by Carlos Barria, using a Flir thermal camera, which also shows a point temperature (in Fahrenheit).

It's an interesting set, taken in late July 2023 and which "reveal a Phoenix where concrete on the street registers 150F (66C), outdoor workers’ bodies reach 105F (41C) and homeless people swelter, surrounded by surfaces as hot as 143F (62C)" and it's unusual to see visual and thermal images matched in this way: you can swipe between the two.

The link is here: Thermal images of the US heatwave in Phoenix, Arizona

Monday 10 July 2023

Infrared generative AI

I've been 'playing around' with a couple of generative artificial intelligence engines that carry out text-to-image. I was interested in how they understood the look of an infrared photograph.

This was partly because I find that at least one of my IR photos has found its way into the models used for generative AI. Without permission of course!

I tried a fairly simple shot; that of a tree. A good test for the basic Wood Effect. The results are quite good and, given how unreal IR photos can look anyway, it would be difficult to tell from the real thing. Sometimes the background detail gives things away but I found I could quickly get good results.

The two I tried are Stable Diffusion and Adobe Firefly (chosen simply because I have access to them) and the text prompt is the same for each: Infrared image of an oak tree in a meadow.

This is the Firefly result ...

As you can see, I got a false colour image without specifying, and in this case it's not a bad result. Often the system would put arbitrary colour washes over the image, but here the result is as you'd expect.

This is the Stable Diffusion result ...

Here, it's black & white straight away. Again, a pretty good result.

I did also try to generate some thermal images but neither engine could get anywhere near what you'd expect, presumably because there are not many, if any, thermal images in the training set.

Sunday 11 June 2023

James Jarché Infrared

I've mentioned in a previous post that the famous press photographer, James Jarché, had experimented with infrared photography in the early 1930s. I also noted that he had used IR to document the photographic manufacturing process for Ilford.

I recently managed to buy a copy of his memoir, People I Have Shot, and this includes some plates. One of them was taken by an unknown Ilford employee showing Jarché taking one of the photographs at Ilford's factory.

Here it is, captioned The Author Shot by Infra-red Rays.

Although in darkness, here you can see Jarché with his camera on a tripod, pointing a little to the right of the viewpoint.

Sunday 12 March 2023

Barnaby Attwell infrareds in Falmouth exhibition

Having recently discovered Barnaby Atwell's faux-colour infrared shots of Cornish landscapes I was delighted to find that he has some included in a new seasonal exhibition in Falmouth.

The exhibition is called Unfamiliar Territory and is on at the Falmouth Art Gallery until June 1st.

The exhibition press release describes the event ...

Unfamiliar Territory is a stunning new exhibition opening this February at Falmouth Art Gallery that will explore a range of themes linked to the Cornish landscape. It brings together an exciting selection of 20th and 21st century artists who have been inspired by Cornwall’s diverse landscapes to create works that show it in innovative ways and explores how Cornwall’s iconic landscapes have evolved over the years.
The exhibition runs from the 11th February to 1st June 2023 and will feature nationally renowned artists such as: John Tunnard, Wilhelmina Barns-Graham, Kurt Jackson, Danny Markey, Tom Cross, Patrick Heron, Albert Reuss, Bryan Wynter and more.

... and Barnaby adds that the gallery shop will be selling copies of his excellent book, Welcome to St Decay, as well as prints and postcards.

The web site for the exhibition is at and Barnaby's blog post about it is at

[Photo courtesy of Barnaby Atwell]