Quote-unquote

When reworking my Invisible Light web site (link here) I decided to include a few quotes that seemed relevant for the subject of infrared photography.

One, I copied from Walter Clark's Photography by Infrared and which comes from William Henry Fox Talbot, in his 1844 book The Pencil of Nature.

... the eye of the camera would see plainly where the human eye would find nothing but darkness.

It's likely that Fox Talbot was aware of Herschel's discovery of infrared about 20 years earlier but whether he's thinking of this, or just of generally being able to see something otherwise invisible, I don't know. The current legal definition of a photograph includes any image using any form of radiation that can be made visible, so does not just include the visible spectrum.

It is difficult, if not impossible, to determine exactly when it was realised that what you see is not all that you get, at least when it comes to the electromagnetic spectrum. Certainly, the remarkable Émilie du Châtelet, in her 1738 paper called Dissertation sur la nature et la propagation du feu suggested that

... there are other colours [emitted by stars] in Nature than those we know in our world.

Although such colours would turn out to be invisible. The simple French belies the significance of the idea.

Il est très-possible que dans d'autres systêmes, il y ait des Soleils qui projectant plus de rayons rouges, verds, &c. que les couleurs primitives des Soleils que nous ne voyons point soient différentes des nòtres, & qu'il y ait enfin dans la Nature d'autres couleurs que cells que nous connissons dans notre monde.

William Herschel in his paper Investigation of the Powers of the Prismatic Colours in 1800 is probably the first to give a name to these new rays ...

... radiant heat will at least partly, if not chiefly, consist, if I may be permitted the expression, of invisible light.

The first use of the term infra-red that I tracked down (via the OED, where else) is from 1881 in Nature; a lecture on solar physics by Captain (later Sir) William de Wiveleslie Abney.

HP Lovecraft, in his 1924 story From Beyond, was somewhat more worried about what might be revealed than Herschel or Fox Talbot ...

With five feeble senses we pretend to comprehend the boundlessly complex cosmos, yet other beings with wider, stronger, or different range of senses might not only see very differently the things we see, but might see and study whole worlds of matter, energy, and life which lie close at hand yet can never be detected with the senses we have.

Roger W Hicks in his 1992 book Successful black-and-white Photography: A practical Handbook was not too fond of the medium.

Apart from its novelty value, I cannot see much reason to use infra-red film other than for scientific purposes. When you have seen a few infra-red pictures, you have seen the lot.

He's not alone: even Ansel Adams was sceptical though he did admit it could work in the right "imaginative" hands.

My favourite, to finish and to contradict HP Lovecraft,  comes from a book about early television, by Ronald F Tiltman in 1927. He has a chapter on Logie Baird's infrared television system, Noctovision, and says ...

Infra-red rays…are quite well-known and highly respectable rays, and have no connection with any much-talked-of death ray or other mysterious rays.

Concerning a visit to Bath

A recent visit to Bath included the Herschel Museum of Astronomy, which occupies a house where William Herschel and his sister Caroline lived and is also home to the William Herschel Society. This isn't the location of his famous discovery of infrared radiation (by then he had moved to Slough) but it is from where he first observed the planet Uranus in March 1781. If you're in Bath I recommend a visit. It should give you some measure of the man and his times and will also remind you of how important a scientist his sister Caroline was as well.

While there I discussed the infrared discovery with the staff and was shown a section of the Herschel Chronicles book (originally published in 1933 and now available in facsimile) which includes correspondence between Herschel and his patron Sir Joseph Banks. The Chronicle's author notes that Herschel, as was common at the time, thought radiant heat was fundamentally different to light. We now know that the two are different only in their wavelength.

Banks is encouraging Herschel to use the term 'Radiant Heat' rather than Caloric, which Banks linked to the 'French system of Chemistry'. Time has proved Banks correct and Herschel was glad to take his advice, saying he was 'very ready to change the word Caloric for Radiant Heat, which expresses my meaning extremely well'.

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.