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  #1  
Old September 27th, 2010, 08:34 AM
Doug Kerr Doug Kerr is offline
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Default The "digital negative" metaphor

Probably about the time of greatly-increasing interest in using the raw output of digital cameras, it became popular to explain the significance of the raw file as being rather like the "negative" in film photography. Usually, there was no counterpart: the actual image file was not said to be equivalent to any object in film photography (although some said it is like "the print").

This metaphor was somewhat solidified with the development of Adobe's raw data format, which they define in their "Digital Negative (DNG) Specification".

But the metaphor is not accurate, and overly-literal reliance on it can mislead us (or others).

In film work, the term "negative" is almost always taken to mean the developed negative, and that is appropriate: the exposed but undeveloped film does not carry either a "negative" or "positive" image - only a latent image. For "negative-type" film, when we process this in the conventional way, we get a negative image, but we can also process it so as to get a positive image (although of course that is best done with "reversal" film, intended for that scheme).

In fact, the closest correspondence of our raw file is to the "undeveloped film".

For example, in the case of film, if we have in hand the undeveloped film, we can choose to develop it in different ways, for example in a way that increases the effective ISO sensitivity of the film (if we have, inadvertently or intentionally, exposed it with less than "standard" exposure).

In the case of color negative photography, we can choose to develop the film in a way that will apply white balance color correction (more about this later).

And, by way of comparison, we have all these options, and others, when we extract an actual image from our digital raw file (an operation often called, quite aptly in my opinion, "development" of the image).

An important distinction is that, in the case of film, once we have developed it using one "recipe", we cannot later develop it again with a different recipe. In the case of our raw file, we can develop it as many times as we wish, using a different recipe each time, so as to get different results - perhaps searching for the "best", or perhaps to derive different images for different uses.

So our raw file is perhaps best considered the equivalent of the "undeveloped film". What about the image we get by "raw conversion" or "development"? Well, it is perhaps most like the "developed film". (I did not say, "the developed negative", since normally it is a positive, not negative image).

Now, if we really want to complete our suite of metaphors, what is closest to the print in film photography? Well the print, or in fact, the image as displayed on a screen.

So I encourage you, when you are explaining the concept of the raw file to a colleague (perhaps new to serious digital photography), to be careful about saying it is "like the negative in film photography". If the listener actually knows better, this may do more harm than good - he may have trouble getting this to gel in his mind.

I will close with an anecdote about the fact that we can only develop film once. In Stanley Kubric's epochal 1968 film, "2001: A Space Odyssey", there was a scene that would composite live action with an elaborate scale mockup of some part of the spacecraft. For some logistic reason (I forget the details of the incident these days), the live action could only be shot at a certain time (I think one of the actors would then go onto another production elsewhere) before the mockup could be completed (it was very complex). (The film had a very long post.)

Kubric (and his D/P, Unsworth, I believe it was) were obsessed with maintaining color balance consistency in composited shots. Accordingly, the undeveloped film from the live action shots was stored for some while (I think it may have been over a year) in an air-conditioned vault, along with many color test shots on the same film stock.

After the shots of the mockup were done (along with many test shots on that batch of stock), test shots from both components were developed and colorimetric observations made. Based on that, development "recipes" for each, hopefully to attain the proper colorimetric consistency, were use to develop other test shots, and the process iterated until the "ideal" pair of recipes was determined.

The actual footage of the live action scene, and the much-later-shot scenes of the mockup, were then developed using those respective recipes, and then the compositing went forward.

So imagine how blessed we are today to be able to keep our "undeveloped film", even after we have once "developed" it. If some critic says, "cute girl, but she looks awfully orange", we can go back and "develop" the raw file again, with a different white balance color correction vector, or other choices of processing parameters.

Meanwhile, I describe my raw files as being like "raw files".

Best regards,

Doug
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  #2  
Old September 27th, 2010, 11:11 AM
Ben Rubinstein Ben Rubinstein is offline
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Let me ask a question. What difference does it make? I agree with your point that the raw file is closer to the undeveloped negative in theory but in practice as it gives more latitude (theoretically) than a developed neg, any mistake a newcomer may make would be in being more cautious not less. If we actually look at this from the perspective of the real world of shooting and using common RAW developers we find that the analogy is a lot closer in fact, although there may be more latitude in a raw file, it takes quite an expert to tap into it and the only ones who might be confused are a generation of film shooters who processed by hand and that seems to be almost a dying breed.

I agree with you on principle but I'm not sure if it is actually true in day to day practise and would advance the theory that it's academic in any case.

Let's compare RAW files to 'film' not a negative. It's far more accurate. I still think it's irrelevant though. Just how much longer will we compare anything to film in any case?
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  #3  
Old September 27th, 2010, 01:27 PM
Doug Kerr Doug Kerr is offline
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Hi, Ben,

Quote:
Originally Posted by Ben Rubinstein View Post
Let me ask a question. What difference does it make?
It makes no difference.

If the common metaphor helps most people grasp a concept with which they may have been previously unfamiliar, then that's great.

Quote:
I agree with you on principle but I'm not sure if it is actually true in day to day practice and would advance the theory that it's academic in any case.
I'm not sure I know what academic means in this context. Does it mean "true, but not of any importance?"

(We former college presidents are a little sensitive about that!)

Quote:
Let's compare RAW files to 'film' not a negative.
I think that's what I said.

Quote:
It's far more accurate. I still think it's irrelevant though. Just how much longer will we compare anything to film in any case?
It would in fact certainly better if we didn't do that at all. I don't.

Best regards,

Doug
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  #4  
Old September 30th, 2010, 10:49 PM
Asher Kelman Asher Kelman is offline
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Doug,

I think that the great potential for creativity at the hands of the photographer is aptly expressed in the metaphor of a digital negative. The sheet of processed film has stabilized information written securely on a sheet of film as silver grains. The RAw file does the same with digital coding.

In both case, from that point time on, one can chose so many ways of building a photograph. So to me, one who has worked many hours in the darkroom and many more hours by the computer, the metaphor fits perfectly!

Asher
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  #5  
Old October 1st, 2010, 06:43 AM
Doug Kerr Doug Kerr is offline
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Hi, Asher,

Quote:
Originally Posted by Asher Kelman View Post
I think that the great potential for creativity at the hands of the photographer is aptly expressed in the metaphor of a digital negative. The sheet of processed film has stabilized information written securely on a sheet of film as silver grains. The RAw file does the same with digital coding.

In both case, from that point time on, one can chose so many ways of building a photograph. So to me, one who has worked many hours in the darkroom and many more hours by the computer, the metaphor fits perfectly!
It doesn't for me. For me, the closest parallel to the raw file is the undeveloped film. We have the opportunity to develop it into an image (a negative image, in the case of negative film) in different ways (just as we can develop a digital raw file into an image different ways). We can "push" development to overcome the effect of perhaps-inappropriate exposure. Although photographic enthusiasts seldom do, we can develop color film so as to apply white balance color correction for the specific illumination of the scene (often done in commercial cinema work).

And we certainly can do these very same things when developing a digital raw file.

But we cannot develop a film negative in different ways.

Of course, in the next stage, we have great flexibility in printing from an existing film negative, just as we have great flexibility in printing from a developed digital image (perhaps a JPEG, TIFF, or PSD file).

Of course, as with all metaphors, there is no complete equivalence. (That's why it is a metaphor, not a fact.)

Best regards,

Doug
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  #6  
Old October 1st, 2010, 07:40 AM
Asher Kelman Asher Kelman is offline
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Quote:
Originally Posted by Doug Kerr View Post
But we cannot develop a film negative in different ways.
But we certainly can with major changes in outcome: grain size, contrast, detail, tonal scale etc!

We just use different combination of temp, developers, concentrations, agitation etc!

Asher
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  #7  
Old October 1st, 2010, 07:53 AM
Doug Kerr Doug Kerr is offline
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Hi, Asher,

Quote:
Originally Posted by Asher Kelman View Post
But we certainly can with major changes in outcome: grain size, contrast, detail, tonal scale etc!

We just use different combination of temp, developers, concentrations, agitation etc!
No, we cannot do that to the negative (which has already been developed, one way or another).

We can do that to the (yet) undeveloped film (which is not yet "a negative").

Which is the essence of my distinction.

Best regards,

Doug
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  #8  
Old October 1st, 2010, 10:08 AM
Mark Hampton Mark Hampton is offline
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Quote:
Originally Posted by Doug Kerr View Post
Hi, Asher,


No, we cannot do that to the negative (which has already been developed, one way or another).

We can do that to the (yet) undeveloped film (which is not yet "a negative").

Which is the essence of my distinction.

Best regards,

Doug
Doug,

Bleach and Selenium when applied to a developed negative change - grain / tonality etc.
Scratching changes the surface.... After development there are many ways to alter the negative before printing.

just a thought !

cheers
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  #9  
Old October 1st, 2010, 10:37 AM
Doug Kerr Doug Kerr is offline
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Hi, Mark,

Quote:
Bleach and Selenium when applied to a developed negative change - grain / tonality etc.
Scratching changes the surface.... After development there are many ways to alter the negative before printing.

just a thought !
Good point - it as not a clear as I made it sound.

Thanks for the input.

Best regards,

Doug
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  #10  
Old October 1st, 2010, 11:13 AM
Mark Hampton Mark Hampton is offline
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Quote:
Originally Posted by Doug Kerr View Post
Hi, Mark,


Good point - it as not a clear as I made it sound.

Thanks for the input.

Best regards,

Doug
Doug,

I have been thinking about this since you raised the points in your original post... I teach classes (just leisure ones) and I use the Latent Image - Negative - Print from film metaphor. I will come back to this and pick your brains some more on this....

Its raises for me an interesting idea - Is digital photography a new medium per say?


Anyway I am off oot for a few beers !

slàinte
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  #11  
Old October 1st, 2010, 11:25 AM
Doug Kerr Doug Kerr is offline
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Hi, Mark,

Quote:
Originally Posted by Mark Hampton View Post
Its raises for me an interesting idea - Is digital photography a new medium per say?
Well, actually no "technique" is a medium, if we accept the definition of medium (in this context) as something that carries an image.

But digital photography is a technique that uses a medium not used in earlier forms of photography.

Of course if we embrace the meaning of medium as used (in what is thought to be its plural form, actually the plural of its Latin ancestor) in "broadcast media", then photography is the "medium", and digital, or film, or large format, or Polaroid, or whatever is not part of the description. (I'm reminded of the near distant past when, for example, one was asked to submit a photograph with a passport application, but "digital photographs" were not accepted.)

Best regards,

Doug
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  #12  
Old October 1st, 2010, 03:51 PM
Asher Kelman Asher Kelman is offline
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Quote:
Originally Posted by Doug Kerr View Post
Hi, Asher,


No, we cannot do that to the negative (which has already been developed, one way or another).

We can do that to the (yet) undeveloped film (which is not yet "a negative").

Which is the essence of my distinction.

Best regards,

Doug
We can do that to both. The negative, can as pointed out already be bleached, scraped and drawn on. It can also be duplicated and then parts multiplied in a sandwich, aligned perfectly or not at all. There's an enormous creative potential, processed already or fixed and discovered in an old shoe box. The breadth of choice is so large that for all practical purposes, the digital negative and the sheet of processed or unprocessed film have limitless potential for the creative photographer.

Asher
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  #13  
Old October 1st, 2010, 05:38 PM
Doug Kerr Doug Kerr is offline
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Then there's always the digital positive:


Douglas A Kerr: Carla Red Fox (digital positive]

And the negative digital positive:


Douglas A Kerr: Carla Red Fox (negative digital positive]

We also have the digital negative (which is positive):


William Robert Thompson: Orange Girl (digital negative)

And the negative digital negative:


William Robert Thompson: Orange Girl (negative digital negative]

Wow! This is complicated!

Best regards,

Doug
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  #14  
Old October 1st, 2010, 06:59 PM
Doug Kerr Doug Kerr is offline
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The equivalence must work this way if the raw file corresponds to the film negative. The equal signs join objects alleged to be equivalent. Underlined phrases are processes.

Code:
Film technique               Digital technique

Unexposed film               Space on a memory card?
    Exposure                     Exposure
Exposed film                 No real equivalent here
    Developing
Negative=====================Raw file
                                 Raw conversion ("developing")
No real equivalent here      Image file (e.g., JPEG)
    Fiddle with negative         Edit image file
Modified negative            Modified image file
    Printing                     Printing
Print                        Print
Note that, although we can "fiddle with" a film negative (bleach it, dye it, paint on it, scratch on it, write on it in black ink) we cannot really "fiddle with" ("edit") the raw data.

Now to me, it looks like this:

Code:
Film technique               Digital technique

Unexposed film               Space on a memory card?
    Exposure                     Exposure
Exposed film=================Raw file
    Developing                   Raw conversion ("developing")
Negative                     Image file (e.g., JPEG)
    Fiddle with negative         Edit image file
Modified negative            Modified image file
    Printing                     Printing
Print                        Print
Best regards,

Doug
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  #15  
Old October 1st, 2010, 09:00 PM
Asher Kelman Asher Kelman is offline
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Doug,

You are obsessing on it. Let me guide you, if I may. Metaphors provide a "sense" of some of the strongest and most relevant attributes we wish to apply to another situation. A digital negative does exactly that. You see things as too concrete, (another metaphor) and so you just continue to struggle with and parse with the poetic nature of the tool of the metaphor.

With a negative, film or digital, whatever stage of processing, we have freedom to be creative in innumerable ways. As you have not been so steeped in the darkroom mystique with periods of processing and iterations in methodology spanning 6 months at a time, for one picture, you seem to have no feel of the real closeness of one process to another. The most significant differences between digital and classic negatives is that the latter required 1000 times more time and skill than working with digital versions of the same general ideas. If I have not convinced you thus far, I will offer you the following solution:

Just as you believe in the worthiness of yourself, you church and the key to you house, I ask you to simply trust me, it reasonably accurate, to say that the metaphor of the digital negative is indeed worthy, valid, apt and useful!

Asher
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  #16  
Old October 1st, 2010, 09:24 PM
Doug Kerr Doug Kerr is offline
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Hi, Asher,

Quote:
Originally Posted by Asher Kelman View Post
As you have not been so steeped in the darkroom mystique with periods of processing and iterations in methodology spanning 6 months at a time, for one picture, you seem to have no feel of the real closeness of one process to another.
Which two processes, exactly, are you comparing? Is it everything from:

• In film technique, everything from taking the exposed film into the darkroom until the print is in hand

and

• In digital technique, everything from loading the raw file into the computer until the print is in hand?

I think those two things are are quite comparable.

or is it:

• In film technique, everything from taking the developed film out of the tank until the print is in hand

and

• In digital technique, everything from loading the raw file into the computer until the print is in hand?


Best regards,

Doug
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  #17  
Old October 1st, 2010, 09:31 PM
Asher Kelman Asher Kelman is offline
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Doug,

When a metaphor gives such kniptions, it may not be for you!

Asher
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  #18  
Old October 1st, 2010, 10:02 PM
Doug Kerr Doug Kerr is offline
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Hi, Asher,

Despite my sad lack of experience (I never took an image from the camera through the darkroom to a print until about 1947), I well recognize that when the digital photographer starts with an earlier stage of the image than an ex camera JPEG file, she has a far greater range of control and influence, comparable to what a film photographer working in a darkroom enjoys (although, as you aptly point out, with far less agony).

My point is that the digital photographer starting with a camera raw file does not just enjoy flexibility comparable to what a film photographer has starting with the negative. She enjoys flexibility comparable to what a film photographer enjoys starting with the exposed film.

If you feel it helps explain this basic concept, and its advantages, to people better by saying:

"the raw file is sort of like the film negative"

than by saying

"the raw file is sort of like the exposed film"

(and I cannot imagine why it would), or if you think the widespread use of the "negative" metaphor gives it gravitas, and so to adopt another one would spoil the party, then help yourself. It's only a metaphor.

Or perhaps you feel that "negative" is a perfectly good synonym for "exposed (but undeveloped) film". Then, of course, it is all the same.

Quote:
When a metaphor gives such kniptions, it may not be for you!
I'll look up kniptions in the morning. As I recall, they give me a very heavy feeling in the stomach. (Oh, no, that's knishes.)

And the metaphor is absolutely not for me. I never use it (and I think I have explained why).

Best regards,

Doug
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  #19  
Old October 2nd, 2010, 09:28 AM
Asher Kelman Asher Kelman is offline
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Default "A RAW file is, in a way of speaking, a digital negative" with endless potential!

Doug,

You have brought us as a profoundly simple thought:



"A RAW file is, in a way of speaking, a "digital negative", processed or not, with boundless possibilities for the creative photographer"



It's as simple as this. A digital negative has the potential of at least the fixed film negative and also the unprocessed sheet of film. Knowing what one can do with either, tells us there's endless creative choice to be had from a RAW file.

Asher
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  #20  
Old October 2nd, 2010, 09:33 AM
Doug Kerr Doug Kerr is offline
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Hi, Asher,

Quote:
Originally Posted by Asher Kelman View Post
You have brought us as a profoundly simple thought:

"A RAW file is, in a way of speaking, a "digital negative", processed or not, with boundless possibilities for the creative photographer"

It's as simple as this. A digital negative has the potential of at least the fixed film negative and also the unprocessed sheet of film. Knowing what one can do with either, tells us there's endless creative choice to be had from a RAW file.
Well said.

Best regards,

Doug
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