Monday, November 1, 2010

Can Digital Cameras Make Photographs?


Film and digital technologies are often treated as interchangeable terms when discussing photography because both can produce an image, but are these technologies indeed interchangeable?

Every medium is distinguished by a unique set of properties which in turn affects the meaning of work produced within that medium. Digital cameras are built to mimic the function and ergonomics of film cameras and so it is useful to examine the nature of film technologies when attempting to understand the current state of digital camera and sensor technology.

When using a film camera, light reflects off objects and passes through the lens where it is focused onto a piece of film. Colour film is made up of layers of light-sensitive material called emulsions, each of which are sensitive to different wavelengths of light, most often that of red, green and blue. Each layer of colour emulsion is actually monochromatic and when all layers are overlaid a colour image can be formed. These layers typically contain silver halide crystals (grains) and colour dye couplers in a base of gelatin. Silver halide crystals are naturally sensitive to light and once exposed a chemical reaction occurs that alters each crystal, invisibly allowing a latent image to be formed by the altered crystals in the emulsion. The film is then developed in chemicals which cause the affected silver halide crystals to react and interact with the colour couplers producing clouds of coloured dye in those areas. More chemicals are then used to remove the silver halide crystals leaving only the dye.1

Film photography operates in a purely physical space and is purely objective in its record of the forms and values of the light projected onto it. The visible final image of the developed film exists as a linear physical trace of the light that was projected onto it, a record of the light that was reflected from the original scene and the interaction of this light with the film. The image on the film thus contains similarly positioned and proportioned forms and values to the light that was projected on it.

It is similar to if one were to throw a rock against a fence leaving scrape marks on that fence. Such marks become an index of that rock. The fence after such an event continues to persist with these marks, preserving the evidence of its interaction with the rock. The marks describe the rock and act as a pointer to the rock. Photography works in the same way. Translated from the Greek root words, photo means “light” and graph means “draw”. At the level of semantics, the term photography implies a visible physical record (drawing/ writing) through an affection by light. A photograph is a persisting artifact of a physical interaction between light and a light-sensitive medium.

The image on developed film is an original. Prints can be made from film by projecting light through the film onto light-sensitive paper, but the film itself cannot be duplicated exactly. Such prints are themselves new photographs of existing photographs (the film). Likewise, exposing photographic paper with lasers using LightJet, Chromira, Fuji Frontier, etc, printers produces new photographs, photographs of lasers. Inkjet printers in contrast are in essence a form of painting.

It is at the fundamental level of function, the recording of light, that digital camera sensors diverge from film. Digital camera sensors utilize analog elements at their core. There are various configurations of these sensors currently in use. Most consumer digital cameras use either the charge-coupled device (CCD) or the active-pixel sensor (APS or CMOS). Both of these sensor designs function in similar ways. Each uses an array of microscopic photodiodes which are capable of independently generating electrical currents linearly proportional to the intensity of light they are exposed to. The electrical currents produced are sequentially fed through an analog-digital converter which yields digital values that are then stored in a digital memory. Since each photodiode is capable of measuring luminosity only, solid coloured filters (red, blue and green) are positioned over each photodiode in an alternating checkered pattern called a Bayer filter mosaic. Each photodiode is covered by a single colour and measures the value for that colour alone. The digital values collected from these photodiodes are then interpolated by software involving complex algorithms. A list of colour values is calculated by this software, combining the red, blue and green values into a fuller chromatic spectrum. The raw digital data cannot form an image without interpretation as it is simply a list of electrical current measurements.

Where film generates a physical record, the electrical measurements of light created in a digital sensor are temporary. The resulting image information is not a trace to some original light as it is with film but is a measurement turned statistic. The colour statistics produced are arbitrary and abstract in their signification of the values originally measured.

There is nothing inherent to the digital image file that makes it an image. Digital image files contain sets of binary-based numeric values acting as a code which requires a key for translation into an image. While digital image files are typically produced with the intention of using specific software to interpret the data, the symbolic nature of the values in these files does not predestine their interpretation to any one software program, leaving interpretation completely open. Different software programs can interpret the data differently, such as text or hex editors which will not interpret the data into an image that resembles the light originally projected onto the sensor. The data can easily be interpreted into other mediums like sound instead of light. Even different programs intended to display images often interpret these colour values differently. Monitors and printers also vary greatly in how they display these interpreted colour values.

The digital image is not inherently visual; it is abstract and has no visual or physical form. The digital image is not fixed and finds its base description in language rather than physical value. There is no original in digital imaging and every copy is identical (one might also argue that there are a theoretical infinite number of identical originals, if the notion of the original is not associated with the physical object and is applied to the idea or symbol).

The digital image operates in a purely symbolic space and is purely subjective, a significant contrast to the film image’s purely physical and objective nature. As a set of data, the digital image has no direct connection to the scene that was photographed; its relationship to that scene is obliterated by the symbolic basis and origin of that data, data which has also been affected by screens of constructed data and second and third-hand representations (and manipulations) of that data. Digital images are a type of computer rendering similar to motion capture and computerized roto-scoping where measurements are made from objects and then visually rendered in virtual as a simulation.

In film photography, decisions that impact the way light will affect interaction with a medium are made before the exposure when the film chemistry or photographic paper is produced and selected. Once a photograph is produced, it is fixed. Any manipulation or change enacted after the production of the photograph, such as physical manipulation or environmental factors, are effects on the original photograph and do not produce a new photograph.

With digital imaging, a photodiode is a generic translator of light and any decisions must be made post-exposure either in the camera’s software or a user’s software. Commonly there are of course Bayer, ultra-violet and anti-alias filters that may have been placed over the sensor or filters placed over the lens, however these filters are effects and not affects; filters do not affect or change the way light interacts with a medium (and in the case of the digital sensor there is no medium to affect), rather filters change the light itself before any potential interaction can occur.

Given that digital image data is completely subjective in nature it lacks authenticity as it has no finalized form—its essence is effect-based. This is in direct contrast to film’s affect-based nature. A digital image edited with a software program like Photoshop is no more or less authentic than the image data delivered from the digital camera or any other kind of image data. All digital images are purely orphaned data, meaningless simulacra that lack an inherent object or form to dictate existence. Digital images can only be seen as images through other media, like an LCD display or a printer.

Film photography produces a still image because of a limit in the material media of film itself. As film is exposed, the reaction to light causes a change in value. There is a material limitation to the amount of exposure film can endure before this reaction fades and ceases, the change in value having reached a maximum. After a certain amount of exposure the film becomes uniformly exposed and thus devoid of detail (in which case it remains a record of light, just one without a visible differentiation of detail). Film produces an image most similar to the way a person might have perceived the light shone on it when a balanced reaction in the film is enacted, a midpoint between a reaction of nothing and everything.

Here also digital image capture differs from film as the effect that occurs when the photodiodes are exposed to light results in the production of a constant and perpetual electrical current. Digital sensors are typically configured to store this current in an additive fashion, and this storage occurs after and apart from the translation of light to energy by the photodiode. While the silver halide grain reacts to light for only a limited duration before a maximum saturation of affect is reached, the photodiode is capable of converting light to current indefinitely. In a sense it is not a “light-drawing” but a “light-measurement” as no drawing or interaction is made, only a measurement and then release of light-energy. The light does not interact with the sensor but is preserved as energy, energy which is transferred to electrical current by the photodiode. There is no reaction or transformation, only a direct translation to electricity which is then measured before the energy of the light is purged and released from the sensor. Where the film photograph exists as an object, the digital image is virtual and a simulacrum.

A constant value can be produced by a photodiode in place of film’s forced dynamic value. There is no physical limitation for the photodiode's conversion of light energy to electrical current. Light hitting the photodiode could potentially be measured indefinitely even as it changes, resulting in a ceaselessly dynamic stream of light information.  Streaming light measurement, a potential underlying nature of digital image capture, calls into further question the relationship of digital image capture to photography and would appear to suggest that it is potentially something else, something which to my knowledge is not precisely defined at present. The potential capabilities of digital image capture are similar to video but present a new form, a seamless and fluid flow of information without inherent visual form and without frames in an undelineated and indefinite measurement. It is a medium of statelessness and statistics. The sensor for digital image capture can be programmed and physically configured to produce still images, but this act truncates the potential of this technology by isolating a fragment of a larger body of potential statistics.

Photography is a narrow field defined by a medium which has interacted with light and remained altered (an imprinted embodiment of that interaction). Digital cameras simulate the results of photography but generate image information only and not physical photographic information. Digital sensors measure light and are not affected or altered in any way by light. The mimicry of film technologies by digital cameras is detrimental both to the progression of digital technologies and to the practice of photography in which film and other photographic technologies are at risk of becoming displaced and lost in favour of a technology incapable of performing the same function, a technology ultimately destined for other largely unexplored functions. Such unexplored functions are very interesting and it should in no way be taken as a negative that digital cameras are not a photography but rather something new.

The physicality of the photograph is an essential part of its message, not just the representation one might see (perceive) in a photograph. The photograph is the message. The digital image however must find forced refuge in shape-shifting, distorted indexes and virtual representations if it is to be perceived, having no object at its core. One is therefore tempted to ask, what is its message?


1 “How Film Makes Images.” Kodak. 16 Aug. 2010
<http://motion.kodak.com/motion/uploadedFiles/US_plugins_acrobat_en_motion_newsletters_filmEss_04_How-film-makes-image.pdf>


The preceding essay is a revised excerpt from my MFA thesis supporting paper which was submitted in September, 2010. Posted 11/01/2010 and revised 11/01/2010.

18 comments:

  1. "The medium is the message", as Marshall McLuhan famously noted.

    I'm fascinated by this. I will not claim at all to be familiar with the technical details. Moreover, I am intruiged by the metaphorical details, and the amount of questions you have left unanswered. This applies to a lot of technology these days. It does beg the question, though - what can we do with digital?

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  2. Indeed! I think that question is a good one and worth exploring. I think the new line of HDSLRs is a step in exploring what digital image creation technology can do and shows that it need not be limited to the production of images.

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  3. This is a very interesting article but I was wondering where you obtained this definition of photography, upon which your conclusion is based:

    "Photography is a narrow field defined by a medium which has interacted with light and remained altered"

    I agree that photography requires a medium interacting with light, but it seems you have added "remained altered" to promote the idea that using a digital camera is not photography, while permanence does not seem to be a factor in most definitions that I am aware of.

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  4. The Greek root words mean "light-writing" or "light-drawing". If a material does not remain altered, then nothing has not been written or drawn. Light-sensitive material had been known for many years before the invention of photography, and cameras existed too and were commonly used for drawing and painting, but it was only when Niepce, Daguerre and Herschel began to figure out methods to fix the reaction of light-sensitive material that it became dubbed "photography" by Herschel. It is also the term that has been in use to describe photographic materials for nearly two centuries, and as I attempted to illustrate in the essay, a digital sensor works fundamentally differently from any of these previous photographic technologies and thus I think it makes sense to call it by a different name.

    A digital camera passively stores light as current and then measures that light; it is not affected by light.

    In an extreme example I could build a manual digital camera. I could magnify a projection from a camera lens onto a tightly gridded screen (I could make it room-size even) and then start assigning each square in that grid a number based on what color I see in it (or I could even use a tool to measure each square for its light frequency) and I could write these values in a notebook. Then I could take all of those values and type them into a jpg file using a hex editor. Would that still be a photograph? It would make an image that looks like a photograph, but there was no medium, no affect by light. That is how the digital sensor works. If it were to be called a photography, then so should paintings made using a camera obscura. The difference with a digital camera is that an engineer has decided how to interpret each color value instead of a painter.

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  5. The sensor in a digital camera is light sensitive, even if this sensitivity is passive and translated to binary code and the sensor is not permanently altered.

    I would argue that photography existed before Herschel coined the term, and that experiments that failed to fix the image were still photography, such as those conducted by Wedgwood.

    Considering where art is today, I think it is problematic to adhere to such a strict notion of what is and is not photography in the same way it is problematic for one expert to attempt to define what is and is not art.

    Perhaps one could use a camera without film or sensor, just as a way of seeing, and still be practicing photography.

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  6. Nearly everything is light sensitive, that is not a meaningful distinction in this context. A shirt left in the sun becomes warm, for instance. It does not follow that the shirt is then a photograph. Your eyes do not make photographs in your head; they translate light and the brain forms a mental image inspired by that information. Images exist in a realm of feeling not physical space.

    You could indeed argue that (and no doubt such experiments are related), but you had asked about the origin of the term in the context I am using it and my response explained when the term was invented and the purpose it was invented for. Someone else might want the word to mean purple elephants and that’s fine, but that use does not signify the concepts I was writing about. Your original question did not ask about the signifier, it asked about what a signifier signified in my essay. Like your original question, my essay is also unconcerned with signifiers; it is concerned with functions not labels.

    A photograph is a specific material with a specific set of properties, like wood, stone, metal, etc. It is easily defined by those physical material properties because it is not a subjective, culturally defined act like art. What it might be used for is not always easy to classify, but the material itself and its unique properties are.

    Art is made through a use of form, and form can include materials like photographs, wood, canvas, paint, etc, even combinations of materials. It can also include actions and ideas, which are a different kind of form (performance, relational aesthetics, etc). The definition of art has no impact on the definition of materials, so it does not follow that because art is difficult to define that materials must be difficult to define.

    Seeing with an empty camera may apply some of the high-level techniques commonly used when someone makes a photograph. Those techniques could be labeled photography but it’s just a label as there is no photographic act involved. Its form is that of a performance and certainly can be an art. This however has no affect on what makes a photograph a photograph. Certainly that performance is often combined with photographic material to make photographs, and that combination could be an art.

    Such classifications of art or what combining performances and materials might mean fall outside the scope of my essay which is only concerned with photographs themselves and how photographic material differs from digital sensors and the implications this difference creates. I only draw the conclusion that they do different things at a low-level and at a high-level could thus also do different things (and they obviously can), but what those things might specifically be or mean is a topic for someone else or another essay.

    My essay does not use high-level functionality to argue for a distinction in low-level functionality (that would be logically unsound), it does the reverse. Your questions using high-level to low-level arguments about functionality are equally fallacious, like arguing that art is hard to define, therefore practices in art are hard to define, therefore materials in art are hard to define. Rather, a proper use of logic is: materials are easy to define, some uses of those materials are difficult to define, therefore art has become hard to define. Even when argued correctly it is still a different topic from my essay.

    On a related side note, photographs do not require seeing of any kind to be formed and they have little to do with cameras or other tools that might facilitate their exposure; a photograph can operate just as easily without a camera. Photographs do not have to create semblances that allow a human to perceive an intelligible image; they merely react to and record light. What a human chooses to do with those photographs is something else entirely.

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  7. This is as ridiculous as saying ebooks are not books because they aren't printed on paper. Nonsense!

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  8. Those are different in form (they call them ebooks for a reason instead of books) but not content. They both use language, and language, being completely abstract, remains intact and identical regardless of the medium it is transmitted through because it is a medium that is based on semiotics (language is symbolic).

    Language is abstract, and you are comparing two abstract things. The ebook and book are no different than a digital image; they are composed of language (language representing color values in the case of the digital image). The photograph is not abstract or semiotic in any way, it is a physical artifact of a physical event, while the digital image is entirely abstract and semiotic at its core. How is your analogy possibly relevant?

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  9. I don't agree with this sentence:

    "The photograph is not abstract or semiotic in any way, it is a physical artifact of a physical event"

    I think the essence of the photograph is also abstract. What I mean by essence is the thought-stimulus that it triggers in the viewers. How is that different for an image on a monitor vs. an image on a slide film or a print?

    The viewers were probably not privy to the original event depicted in the photograph, and their interpretation might be different.
    In other words, the photographer wanted to share an idea or thought with the viewers and did so in her medium of choice, just like the novelist did in her book.

    I, myself do lot of photography, and an image I made last year makes a totally different emotional impact on me today than what it did at the moment I pressed the shutter.

    Another point: Can you distinguish a hard print from a digital image on a computer and a traditional wet-printed bromide paper image? Can you do so when digital technology catches up?

    Your argument seems to follow Susan Sontag -- "to photograph is to appropriate the thing photographed". No, it doesn't. The image lives entirely in the mind of the viewer, where an idea has been placed by the photographer.

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  10. How then is a photograph abstract or semiotic? A photograph is a physical object. If something is physical, it is not abstract. Semiotics involve signs—culturally agreed upon signifiers and sign processes. Signifiers are not physical elements, they are ideas, symbols, processes. Signifiers can be assigned to physical objects but they are not the objects; like images, they exist as mental constructs.

    Every photograph is physically unique and its physical characteristics are not an agreed upon signifier for anything. Every photograph taken of a dog is different, for instance, even when it is taken of the same dog from the same angle under the same lighting, one after the other. Each is a new physical object. The image one perceives from the photograph of the dog allows one to imagine a dog; but the photograph has nothing to do with the dog beyond its record of the light that hit that dog and interacted with silver crystals. The photograph is an index for the light that reflected off of that dog, not an image for that dog and not the dog itself. In the same way, a hole in a wall from a bullet that passed through it is an index for that bullet. The hole does not signify the bullet in any way, it is a physical artifact of an event between the bullet and the wall. The hole does not represent the bullet. The photograph works in the same way.

    You do understand that photographs and digital images both exist outside of your mind and your experience? [While I use the term digital “images”, I am of course referring to the data set and any mechanical interpretations (manifestations) made from this data, whether printed or interpreted into light, not the image one might perceive from such manifestations.]

    What you perceive (the image, supposed over the photograph or data set) is a mental construction and should not be confused with what something is. So how the photograph or digital image might affect you, be used by you, or be perceived by you is irrelevant to what either thing actually is. What you are saying is the equivalent of saying I can pet a dog and I can pet a toaster, therefore they must be the same thing in every way. The emotional impact an object gives you does not affect the object in any way. It only affects you. Objects (photographs) don’t change by us looking at them; we change by looking at objects. Both photographs and data (such as digital images) are amoral and without any intrinsic meaning beyond their own existence and form. I can take any image and use it to create any kind of meaning just by changing its context.

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  11. What a photographer intends to use a photograph for (as an image, presumably, but not always), has nothing to do with the photograph itself. Images are mental constructs; photographs are not. Digital images are sets of linguistic data, photographs are not. Digital images manifested as prints (inkjet or photographic) or as light on a computer screen are also not images; they are elements in the physical world.

    The photograph is a physical artifact of how light affected a bunch of silver. It is not suppositional for any scene, event or anything outside of that event—it is not the thing photographed. It is not a representation—any representation you perceive is a mental construct, and can be made from any object or data set; it is simply easier to mentally form a recognizable image from a photograph or a digital image because of similarities in appearance to things one has previously seen in the physical world (other images created in one’s mind), but the image seen (not the object or data) is no more meaningful or truthful than those mentally formed from any other kind of object or data (like the moss on a rock that might appear to form a face, etc).

    Again, whether a photograph and digital image look similar or not, or can be used in similar ways, is irrelevant to what they are and does not mean that such similarities are qualitatively universal. The traditional wet-printed bromide print (WHICH IS NOT AN IMAGE) is physically different than the digital “image” on a computer, regardless of quality or similarity in appearance and your ability to mentally equate the images you see in each (appearance is a weak means of comparison anyway, as again, it compares a use-value of one quality only, and it is a mental quality external to the object or data).

    My argument is unrelated to Sontag’s argument as I am saying the photograph does not appropriate anything. It is a new physical object, not an image and not a supposition, and definitely not abstract language. It is an artifact of an event where light reacted with silver halide crystals, and that event alone. It is a physical data and not an abstract data. Any appropriation occurs in a viewer’s mind, not the photograph. The image is NOT the photograph; the image is what one hallucinates when viewing a photograph. Thus without external context, an image can mean anything, even if that image was influenced by a realistic-looking photograph or other object or data.

    It’s like thinking you know what a certain person looks like, when in fact that person’s appearance is in continual flux and that person never looks exactly the same from moment-to-moment, from angle-to-angle, and under changing lighting, yet your mind determines commonalities in these perpetual appearances to form the ability to recognize multiple appearances as being the same person.

    I can identify many instances of the same image, but that does not mean the sources of these images are equivalent in any way; it is simply a capability of my brain and imagination to visually equate similar images and think of them as the same when in fact they are not. If I look at a photograph from different angles I am seeing different images, but I think I am seeing the same image. If I look at a photograph under different colors and intensities of light, I am again thinking I am seeing the same image when that is not the case; my eyes are receiving very different information and light each time, but because images are mental, they can be perceived as the same regardless of the input information for each. Likewise, perceiving the same image from different sources (instead of the same source under different conditions as in my examples) is no different: it is your mind that makes them the same image, and regardless of the image you perceive, the object or data that image is manifested from is completely external with its own unique set of qualities and properties outside of that image.

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  12. [The photograph is a physical artifact of how light affected a bunch of silver.]

    I could say a photograph is a physical artifact of how light affected the electrons in silicon crystals doped with phosphorus. The fact you cannot touch this artifact with your fingers does not make it less physical.

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  13. Where is the physical ARTIFACT in that? Do you use a new sensor for each image and then take each sensor out after its first image and preserve it? How do you fix the affected silicon crystals so that they stop reacting to light, thereby creating a physical artifact?

    If you do all of that, then sure, why not call the sensor itself a photograph. While not required, it would be very difficult to discover the chemicals and process required to make the affected crystals visually distinct if one wished to perceive an image from it.

    Even so, while some silicon crystals may now form a photograph when treated in that manner, it is not a digital image itself, nor were any digital images produced during this process (the sensor does not even need to be powered on for this effect to occur). This potential use of a sensor therefore has no relevance to this discussion.

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    1. Well written, but fundamentally it's philosophical nonsense.

      You've chosen to narrowly define 'photograph' a single, original, physical object. That view is extraordinarily narrow.

      In the modern era, most people consider a photograph any image captured by a camera. If an image appears on a camera your computer screen or television, is it not a photograph (and if not, do you mind if we use your images royalty free online?)

      Your basic argument is that there is no permanent physical artifact produced by a digital camera. But if you choose not to reuse your memory card and record the image in RAW format, why is this less valid than an image captured on film? The bits on the card are just as physical as the chemical effects on your film stock, and both need a great deal of processing (chemical or digital) before you produce an actual image.

      Yes, a film camera can produce a NEGATIVE, which a digital camera can not. But I negative is not a photograph, just like the raw bits on an SD card are not either. But in the opinion of the vast majority of people, they both produce photographs.


      And the final point is this - you say that a digital picture is not an 'image' but a physical picture is. But there is no such thing as an 'image' until it has been printed or otherwise rendered and there is a person there to actually perceive it.

      Since it isn't an image until it strikes the retina of a viewer and it is processed by their brain, that particular argument is invalid.

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  14. "...aving no object at its core. One is therefore tempted to ask, what is its message?"

    Um...I'm struck by the irony of you posting this on a blog, which itself has no physical object at it's core.

    Are you then finding your words distorted, as they have been digitized and indexed? The message is gone or corrupted because there's no hard copy to read?

    Processed photos are just approximations of the final negative, just as digital images are not-quite-perfect measurements. But when I send out a digital image, every copy is perfect.

    My intended quality is maintained and my message - the final artwork that I wish to release to my audience - is perfectly reproduced every time.

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  15. Old film luddite or just retarded? Get out of the dark room and smell real air. Too much film emulsion particles in your head.

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