The Chemical rays of light

[Maris Rusis]

I was prompted by a comment from Jim Collum in the Alternative Prints from Digital Negatives and Positives thread to unpack the phrase "the Chemical rays of light" used by Sir John Herschel in 1839 when he invented the word Photography and explained what he meant by it. First, part of the manuscript of Herschel's lectern notes at that momentous presentation:


http://farm7.staticflickr.com/6203/6108313024_771aa14e01_z.jpg

"Photography" comes first and then the definition of the word is given next "or the application of the Chemical rays of light to the purpose of pictorial representation"

In 1839 no one knew what light was.

Long before, in 1690, Christiaan Huygens said light was travelling system of waves but Isaac Newton insisted that light was a stream of tiny particles. The argument lay unresolved.

In 1800 William Herschel (John Herschel's father) used a thermometer to measure the heat of various colours of a solar spectrum. Red was hotter than blue but to his surprise a region beyond the red, where nothing could be seen, was hotter still. There was something out there, perhaps the "heat rays of light", or maybe it was not light at all because there was nothing visible.

Inspired by William Herschel's example Johann Ritter in 1801 decided to explore the solar spectrum using the known property of light to darken silver chloride paper. Ritter found red light did not cause darkening but as he moved closer to blue the darkening increased. Again surprisingly, maximum darkening happened beyond the blue end of the spectrum. Could these be "chemical rays" that populated some of the visible spectrum but mainly lay beyond it? Using the reasonable supposition that if it couldn't be seen it wasn't light, the "stuff" beyond blue could be something entirely different and strange.

Thomas Young, the famous British polymath, observed, measured, and mathematically analysed optical diffraction effects in 1801. He concluded that light was indeed a wave and that he had actually determined wavelengths; accurately as it turned out. This unleashed a storm of controversy as the pre-eminence of British science was based on the majesty of Isaac Newton and it wouldn't do to prove Newton wrong on anything. Many thought that diffraction was merely the jostling of light particles and Young's wavelengths were merely the size of the particles themselves.

Sir John Herschel himself had found that an image perfectly focussed by eye would be slightly out of focus when recorded by a sensitive surface. There seemed to be a "visual focus" and a "chemical focus" quite close together and the difference between them varied a bit from lens to lens.

Less formal observations had already established that light had many other properties. Strong light would cause fabrics to fade but cause skin to darken. Light getting in the eyes would cause the sensation of sight. A lighted window would attract an indoor potplant to grow toward it.

So what was Sir John Herschel going to say in his lecture of March 14, 1839 in front of the Royal Society? His audience included top scientists, industrialists, millionaire aristocrats, and influential politicians some of whom rejected "infrared", "ultraviolet", "light waves", "diffraction", etc as non-Newtonian and an affront to British superiority.

Herschel trying to be as uncontroversial as possible said "the Chemical rays of light". He wasn't going to argue about what light was and which of it's "properties" was legitimate. He invoked only the property responsible for chemical changes; whatever that was.

A lot happened after 1839. James Clerk Maxwell in 1862 established light as an electromagnetic wave. Max Planck chopped light into quanta in 1900. Albert Einstein brought back light particles in 1905 and got a Nobel Prize for it. Richard Feynman the great American physicist formalised the quantisation of light in his 1965 Quantum Electrodynamics. And even more recently light has lost its individual identity by being combined with the weak nuclear force in Quantum Chromodynamics.

Given all that I say there is a strong case for identifying photography with its original principles. Doing so eliminates at a stroke all the controversies, contradictions, ambiguities, and ad hoc patch up jobs that try to shoehorn computer print-outs into photography, or digital negatives, or scanners, or film writers, or whatever is next in trying to get on the photography band wagon.

I believe that "the Chemical rays of light" is the best sword photography has, it is sharp, it cuts cleanly, and it should be swung freely at pretenders.

[Nathan Potter]

Maris, nice logical and historical buildup on the nature of light, but as a "chemical ray" the conclusion leaves me a bit dumbfounded. In this day and age which one is the pretender? :D

Nate Potter, Austin TX.

[Heroique]

I believe that "the Chemical rays of light" is the best sword photography has, it is sharp, it cuts cleanly, and it should be swung freely at pretenders.

What can we say so Photography will lay down the sword?

I think we need a mediator who's familiar with both sides of this issue.

If we don't find a compromise, and fast, someone's going to cry.

[Struan Gray]

One interesting addition to the timeline is that Maxwell's first great set of experiments, the ones which made his name as a scientist, proved that Thomas Young's theory of human vision was correct, and, as a by-product, threw suspicion on the eye as a judge of the properties of electromagnetic radiation.

But, Maris, you're sailing into waters which are both treacherous and deadly for the purpose you wish them to serve. The more we have learned about how molecules capture light, the less difference there seems to be between them and semiconductors. Charge excitation between the orbitals of organic molecules has exactly the same properties as charge excitation between the energy bands of a crystal semiconductor. Sensitisers work in almost exactly the same way as dopants. Charge separation is necessary, but whether it is achieved through a crystal field stabilising ions or a designed-in potential gradient stabilising electrons or holes is largely irrelevant.

Your 'argument' is based upon a selective promotion of small parts of nineteenth century science over the whole accumulated body of knowledge that we possess today. It is purely semantic – a distinction you are welcome to make in your own personal work and thought, but which has no basis whatsoever in the scientific work you quote in supposed support.

If you really want to learn, you should read Gurney and Mott's paper describing the formation of the latent image from 1938. It is no accident that Neville Mott later won the Nobel Prize for his contributions to Solid State Physics. The paper is available free on the Royal Society's website:

http://rspa.royalsocietypublishing.org/content/164/917/151.full.pdf+html

[jb7]

But, Maris, you're sailing into waters which are both treacherous and deadly ...

If you embark on a voyage today, chances are that the liner will use the term 'set sail' in their brochure. I think it might be unbecoming to argue about the lack of sails if the destination is the important part of the journey. Similarly, if the ship is docked to starboard rather than port, arguing the toss might seem comical to a disinterested bystander.

Language is in constant flux, and although I hate the dismissive, superior, churlish tones of the word 'fauxtography' it can't be denied that it is a word, a word that pigeonholes the utterer as much as that which they mean to describe.

This topic keeps coming back; by the strict definition presented above, perhaps the word 'photography' should only be applied to the 'chemical rays of solar light', as actually written, and which might only apply to pictures taken outdoors using processes sensitive to anything but visible radiation, if those 'chemical rays' determine 'chemical focus', which, after all, are not the same rays that allow visual focus.

I really don't mind the debate, what I actively dislike is the repeatedly expressed distain for most of the people on the planet. Perhaps those using collodion are the only true 'photographers', but I've hung out with some of those, and most of them seem really grounded and not hung up at all...

[Struan Gray]

My ten foot dinghy once nearly collided with H.M.S. Illustrious. Shouting 'Steam gives way to sail!' was no help at all. Telling the crew they weren't real sailors wouldn't have been too productive either.

Ditto the distain.

[Kirk Gittings]

Unfortunately for those with their finger in the dike, language (including words and their definition) is not static. It evolves.

[jp]

Given all that I say there is a strong case for identifying photography with its original principles. Doing so eliminates at a stroke all the controversies, contradictions, ambiguities, and ad hoc patch up jobs that try to shoehorn computer print-outs into photography, or digital negatives, or scanners, or film writers, or whatever is next in trying to get on the photography band wagon.

I believe that "the Chemical rays of light" is the best sword photography has, it is sharp, it cuts cleanly, and it should be swung freely at pretenders.

I enjoyed the history and science, but the conclusion is a tiny bit mad; you're eliminating some controversies and replacing it with a controversial claim of your own. If you don't like computers in photography, don't use them.
Who are the pretenders? I think I know but it's not clearly stated.

[Jim collum]

I brought this point up in the other thread... but 'Chemical rays of light' originally referred to the UV spectrum. If you're taking everything at it's historic verbatim.. that would rule out pretty much anything done with a lens (at least a modern one). Most optics will filter out the UV spectrum. In fact, given we're being very specific here in the definition of photography.. anything exposed with visible light at all wouldn't be considered photography. It would require using UV pass filters for it to quality.. or an emulsion that was only sensitive to UV light.

[Kirk Gittings]

I believe that "the Chemical rays of light" is the best sword photography has, it is sharp, it cuts cleanly, and it should be swung freely at pretenders.

Photographers have no "sword" except the strength of their imagery. It's the image that makes a photographer, and a finely crafted image can be accomplished by many means including digital or hybrid means. Trying to shoehorn the current definition of photography back into an 1839 definition may make one feel superior to the masses but it is actually totally meaningless-a sword swung at windmills. Analogue is now an alternative process. The people you are referring to are preservationists of photographic processes, no doubt a respectable goal and photographers may choose to use those processes to enhance their images-but the process is the process its not the image.

[Jim collum]

this is a debate is pretty much only found in internet forums, with only a handful of people arguing the point any more. The rest of the world (galleries, museums, etc) moved on over a decade ago. Another 20 years, and the general public won't even know what's meant if you use the term film (ask a random sampling of people now and ask them what Wet Plate Collodian is).

While an interesting intellectual debate, it really is irrelevant as far as photography is concerned.



Photographers have no "sword" except the strength of their imagery. It's the image that makes a photographer, and a finely crafted image can be accomplished by many means including digital or hybrid means. Trying to shoehorn the current definition of photography back into an 1839 definition may make one feel superior to the masses but it is actually totally meaningless-a sword swung at windmills. Analogue is now an alternative process. The people you are referring to are preservationists of photographic processes, no doubt a respectable goal and photographers may choose to use those processes to enhance their images-but the process is the process its not the image.

[hoffner]

I believe that "the Chemical rays of light" is the best sword photography has, it is sharp, it cuts cleanly, and it should be swung freely at pretenders.

The "chemical rays of light" expression is nothing else than an expression of insufficiently understood nature of light. Had he said "the chemical traces of light" he would have been right on.
Regardless, trying to save this incorrect definition as a commanding definition of photography is as useful as selling olive oil made of olives harvested by hand as the "true" olive oil. Well, it is in this category, at least. :)

[paulr]

There are layers treacherous water in this kind of argument ... an interesting topic in itself. Interpretation based on the (presumed) intent of an author or founder is only one of many viable options. This comes up in all kinds of hermaneutics, from scriptural study to law (especially constitutional law) to literary criticism.

In this case we have a founding definition based directly on a discredited definition. As the O.P. points out, in 1939 they didn't even know what light was. Yet they coined their definition with the word light in it. Where can we go from that?

And then we have the problems of definitions themselves, which belong not to logic or the physical world but to language. Language is mutable, as many have noted. If we ignore this, and use old versions of the language rhetorically (or attribute new versions of the language to old utterances) we are guilty of lexical fallacy—one of many philosophical ways of being full of shit. Wittgenstein said it most simply (believe it or not): "A word is defined by its use."

[Jac@stafford.net]

Interpretation based on the (presumed) intent of an author or founder is only one of many viable options. This comes up in all kinds of hermaneutics, from scriptural study to law (especially constitutional law) to literary criticism.

You might be interested in a book by Marianne Constable, entitled "Just Silences: The Limits and Possibilities of Modern Law" which answers the question of why we find very little in competent legal scholarship which uses the word "Justice". Methinks the same should be applied to discussions of Art.

[jnantz]

chemical rays of light seems to light as "ether" is to the 5th? element
i can see the difference between "photography" and "photography"
and i guess it is an important distinction to make if you are cataloguing &c
not sure why we have to live on a living history museum or seem like wannabes ...
if the negative was made by another way or is hand made or a found object your and an image created by
light and light sensitive ,materials your definition doesnt allow for it ..
im thinking paper megatives made ny rubbings, xeroxes ink/ laser print or photograms.
and in the end photography should be more inclusive not exclusive

but thanks for the history lesson its nice to know where what we take for granted comes from

[Drew Bedo]

I view the work of the pioneers of photography and physics with respectful awe. They were groping to place aspects of the observed world into a theoretical framework, but didn't have the physical tools or the foundations of modern theoretical physics to work with. Yet even today with the staggering array of technology available and the theoretical tools of quantum mechanics, the true nature of light is still not fully understood. Just as physical scientists do not fully understand the behavior of sand on steep slope, they still do not understand the action of light in the Daguerreotype process. The question of what is the terminology to use is moot.

I can only imagine the feelings of Fox-Talbot and Daguerre when they (each in their own way) found a way to reputedly fix an image. In another age they would have been burned at the stake for black magic!
Rather than explore this corner of photographic discussion much furthe . . .I'd rather go out and shoot.

[Jac@stafford.net]

Drew Bedo: Just as physical scientists do not fully understand the behavior of sand on steep slope,

Exactly, and that is why we employ physical modeling in hydrology and geology so that students and professionals can learn how systems behave. They, hopefully, gain knowledge through experience, then observation which can lead to empirical discoveries.

Similarly, there is the kind of knowledge available (so far) only through carrying out. See "A New Kind of Science" by Stephen Wolfram. I worked without a great deal of success attempting to bring his methods into 3D space. No great success directly, but some new to me insights.

Light? What we experience.

[Drew Bedo]

I can't respond further as I am loading film.

[rdenney]

For me, the simple definition that 1) fits with what most people understand, and 2) can be used to simply resolve controversy is that photography is "making a picture using a camera." And a camera is a device for projecting light from a scene onto a surface. Consider a camera obscura, which had no mechanism for recording that light to make a picture (other than an artist tracing it by hand). It was not photographic because it didn't make a picture. So, what makes a camera photographic is that a picture is made--and that requires a technology for recording it. The essential element of photography is that a picture is made, and that picture is traced by projected light, not by the artist's hand. This definition is entirely consistent with Herschel, and it also presented what was important to him and his time, which was describing what made photography different from the dominant picture-making methods of the day.

Arguments about the technology used to record the light projected onto the surface in the camera would have offended the early photographers, who were all searching for new and better technologies for doing so. They would have seen it for what it is--an attempt to define away those methods the definer opposes for whatever reason.

Herschel was making the point that photography worked by the action of light, not by the action of the artist.

The direct link between the subject and the picture is the beam of electromagnetic radiation that connects them. I learned on this forum that there is a word for such a link: indexical. It seems to me that those aspects of the image that maintain that indexicality are purely photographic, and those that are manipulations directed by the photographer (including the photographer's choice of technologies) are not. Thus, most photography is a mixture of photographic and non-photographic elements. But when the outlines of the picture are indexically linked to the subject, most people consider it a photograph.

We use modifiers when the non-indexical parts are important, such as "hand-colored photograph" or "black-and-white photograph."

This language seems clear to me, and to people I talk to, including non-photographers.

Rick "who is not, however, grinding an ax" Denney

[Lenny Eiger]

Just because you can define a word such as indexical, it doesn't mean its useful. I would agree that an image drawn on a camera obscure is not a photograph. However, there is a clear distinction between a capture process and a printing process. There are many printing processes, some that degrade the image somewhat, some change its color from what existed, etc. I would say that there is no such thing as an indexical print, by your definition, the spectral response is not exact. In fact, it has to be inexact for the person to believe that they are seeing something "real."

There are also inconsistencies in the capture step. Years ago someone put things on top of a scanner and let it go... They were quite interesting. Harumph, not a photograph, many here would say. But then one has to consider how different it is, or isn't, from a digital camera. Now its not about indexicality, but about a lens? But then you eliminate everyone who doesn't use a lens, like the pinhole folks, who surely want to be considered photographers.

This is certainly a discussion about nothing at all. It's only purpose is to say "Im better than you, because I use such and such technology." And the funny thing is that almost of those people don't use the finest technology available. Indexcality, shmindexicality. Photography should have a very wide definition so everyone gets to express themselves however they see fit, new and interesting things happen and we all learn something new every day.

Lenny

[ROL]

Against my better instincts, I was up early at Zabriskie Point in DV last Saturday morning, along with the throngs of lensed hopefuls. The only thing that differentiated me practically from the others, at that moment, was that I was the only one with a view camera, and I'm reasonably certain, the only one who didn't take a picture. I wish I knew what any of that meant. Probably just that I couldn't sleep and was glad to be back in DV again.

[dsphotog]

Rays of light always look better after the viewer has ingested the correct chemicals....

[Heroique]

Indexicality, shmindexicality.

I'm curious if x-ray machine photographs are indexical – let's say of one's cracked skull.

This is beginning to sound like literary criticism.

The bad Derrida kind. :(

[rdenney]

Just because you can define a word such as indexical, it doesn't mean its useful. I would agree that an image drawn on a camera obscure is not a photograph. However, there is a clear distinction between a capture process and a printing process. There are many printing processes, some that degrade the image somewhat, some change its color from what existed, etc. I would say that there is no such thing as an indexical print, by your definition, the spectral response is not exact. In fact, it has to be inexact for the person to believe that they are seeing something "real."

There are also inconsistencies in the capture step. Years ago someone put things on top of a scanner and let it go... They were quite interesting. Harumph, not a photograph, many here would say. But then one has to consider how different it is, or isn't, from a digital camera. Now its not about indexicality, but about a lens? But then you eliminate everyone who doesn't use a lens, like the pinhole folks, who surely want to be considered photographers.

Nothing about indexicality requires a lens. A pinhole can project an image just as easily as a lens can.

And did you not read that I said all photographs have some indexical elements and some non-indexical elements? And that people call it a photograph if the indexical part dominates the outlines of the image? You are agreeing with me, even if disagreeably.

There has been a difference between capture technologies and display technologies for most of photography, with the (non-digital) exceptions being stuff like Polaroids and transparencies. With Polaroid one-step prints, the print process is the capture process, as it is with in-camera paper positives such as those made by photo kiosks. And transparencies are not always printed--projection was a common display method. Yet they are all photographs. Making a picture of small items using a scanner (or, earlier, a copy machine, even when they were non-digital) challenges the definitions, but it turns out they still work. Those scanner sensors and copy machines do project an image, and the picture is made by the subject, as influenced by the choice of technology. Just as with a Velvia slide or a black-and-white negative and print. Most if not all scanners use a lens or array of lenses to do so, though it doesn't really matter that they do. Most people call them photographs, and someone doing so is not upsetting the cosmic order (or threatening the extinguishment of the sacred flame).

I've read books about photography written over a century and a half, and the definition most people use (which I summarized, using "indexical" as a shorthand term of art), seems to work pretty consistently for all of them.

Rick "who doesn't mind a term of art if it makes the discussion more efficiently understood" Denney