FILM-some thoughts

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daveswan

Well-known member
These thoughts come from the Perya thread but I'm posting them here.

1st Preamble:
Nothing in here should be construed as an attack on digital.
2nd Preamble:
I am not a film chemist, though I do have a chemistry degree, and read extensively on the topic (A while back now). In fact a film chemist probably couldn't say much more, due to commercial confidentiality.

Points:
1) Film is NOT ANALOGUE.
The nearest equivalent would be with high sampling single bit audio vs low sampling multibit recording. It can only be called analogue in the sense that there is a physical representation of the scene in front of the lens left on the emulsion. But that representation is quantised, just as digital is.

2) Organic Chemicals in film.
There are bucket loads, since without them an emulsion (Not technically correct) would be a) Slow, b) Probably unstable and c) only blue sensitive.
Let's enumerate them:
There are organo-sulphur compounds that act as speed enhancers.
Various electron traps
And most importently, Sensitisation Dyes, the only one I can recall is Erythrosine, but that is obsolete, the newer one are covered by commercial confidentiality, I think (I may be wrong!), but are needed to extend sensitivity into the green and red (Or even Infra-Red) regions, as well as increase the speed.
Colour couplers in colour film, which become colour dyes on development. The exception is Kodachrome (R.I.P.), where the colour dyes are added during development. the residual silver is usually remove during the bleach-fix step, except in a bleach-bypass look.

Obslolete film formats.
Any film can be projected. Since the film is physical, the frame size can be measured, as can the frame spacing, and frankly film projectors aint rocket science, any competent engineer could build one from first principals.

A side note:
Regarding the glass plates I printed, these were not umpteenth generation copies of digital files, but the same plates the long-dead photographer loaded into his plate-holders, exposed in his camera and developed in his dark-room, and which gave me a feeling of connexion with him.

Phew!
Sorry, had to get that off my chest. If you've made it this far thanks for bearing with me.
Dave
 
Film is analog because any copy you make of a film negative- like a print or an IP is not an exact 1:1 clone. You will always get unpredictable differences like unique grain and slight variations in color and exposure from copy to copy. Duplicate a movie file on your hard drive and it will be an identical clone down to the last bit. That's the definition of digital vs. analog.

Noah
 
:undecidedMaybe Film is Digi-Anal. I iz so confuzed right now!

I'm sure there are many examples of things that are not digital that might have certain properties of digital, we still call those things... analog/analogue
 
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Something else about film I was thinking about...

It has a rolling shutter. Rather than simply use global shutters, I'd think those looking for the "film look" would seek to use a shutter like that of the film cameras - rolling horizontally in about 4 microseconds.
 
I thinkl it's a question of samples. Use a old round light dimmer at home and dim the light. You have an infinite number of gradation in the intensity. This is like with a film where you can play with your neg with the variations not distinctive from one choice to another, they all use a curve ( like vertors in graphics).

Now try the sensor touch one and try to dim the light. You will probably have 10 to 20 levels of intensity.

Colour in the digital world is a question of choices available
4-bits 16 (Standard VGA)
8-bits 256 (Super VGA, indexed color)
16-bits 65,536 (High Color)
24-bits 16,777,216 (True Color)
32-bits 16,777,216 + alpha channel

After this their is Redcode which is raw information. This is the type of digital information that is the closest to film until now. You can go deeper in the choices available to you.
 
From the American Heritage Dictionary (Dictionary.com):
Of, relating to, or being a device in which data are represented by continuously variable, measurable, physical quantities, such as length, width, voltage, or pressure.
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From Wikipedia (emphasis mine):
An Analog or analogue signal is any continuous signal for which the time varying feature (variable) of the signal is a representation of some other time varying quantity, i.e analogous to another time varying signal. It differs from a digital signal in terms of small fluctuations in the signal which are meaningful. Analog is usually thought of in an electrical context; however, mechanical, pneumatic, hydraulic, and other systems may also convey analog signals.

An analog signal uses some property of the medium to convey the signal's information. For example, an aneroid barometer uses rotary position as the signal to convey pressure information. Electrically, the property most commonly used is voltage followed closely by frequency, current, and charge.

Any information may be conveyed by an analog signal; often such a signal is a measured response to changes in physical phenomena, such as sound, light, temperature, position, or pressure, and is achieved using a transducer.

For example, in sound recording, fluctuations in air pressure (that is to say, sound) strike the diaphragm of a microphone which induces corresponding fluctuations in the current produced by a coil in an electromagnetic microphone, or the voltage produced by a condensor microphone. The voltage or the current is said to be an "analog" of the sound.

Advantages
The main advantage is the fine definition of the analog signal which has the potential for an infinite amount of signal resolution.[1] Compared to digital signals, analog signals are of higher density.[2].

Another advantage with analog signals is that their processing may be achieved more simply than with the digital equivalent. An analog signal may be processed directly by analog components,[3] though some processes aren't available except in digital form.

Disadvantages
The primary disadvantage of analog signaling is that any system has noise – i.e., random unwanted variation. As the signal is copied and re-copied, or transmitted over long distances, these apparently random variations become dominant. Electrically, these losses can be diminished by shielding, good connections, and several cable types such as coaxial or twisted pair.

The effects of noise create signal loss and distortion. This is impossible to recover, since amplifying the signal to recover attenuated parts of the signal amplifies the noise (distortion/interference) as well. Even if the resolution of an analog signal is higher than a comparable digital signal, the difference can be overshadowed by the noise in the signal.
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That sounds an awful lot like film to me.

Look, the difference between analog and digital comes from the root words. In an "analog signal," information in one medium is represented analogously by another medium. In a "digital signal," the information is specifically represented by numbers and numbers alone. You could hand-write those numbers on a piece of paper instead of storing them in a computer file, but they would mean the same thing. An optical soundtrack is not the same as a vinyl recording or a time-variable voltage.

2) Organic Chemicals in film.
There are bucket loads, since without them an emulsion (Not technically correct) would be a) Slow, b) Probably unstable and c) only blue sensitive.
Let's enumerate them:
There are organo-sulphur compounds that act as speed enhancers.
Various electron traps
And most importently, Sensitisation Dyes, the only one I can recall is Erythrosine, but that is obsolete, the newer one are covered by commercial confidentiality, I think (I may be wrong!), but are needed to extend sensitivity into the green and red (Or even Infra-Red) regions, as well as increase the speed.
Colour couplers in colour film, which become colour dyes on development. The exception is Kodachrome (R.I.P.), where the colour dyes are added during development. the residual silver is usually remove during the bleach-fix step, except in a bleach-bypass look.
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Yes, there are plenty of organic compounds that need to be in a film strip. But none of them determine the "look" of film (as compared to digital). The crux of the film vs. digital debate is really about the look. People love to describe the look of film as "organic." The visual information contained on a piece of film is held by the non-organic silver halide crystals. That's it.

Obslolete film formats.
Any film can be projected. Since the film is physical, the frame size can be measured, as can the frame spacing, and frankly film projectors aint rocket science, any competent engineer could build one from first principals.
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People like to talk about obsolete digital formats as if the information stored on them were unrecoverable. First of all, since we're talking about storing movies digitally, it's not like people are just totally going to forget about those files. That sort of nonsense is par for the course for those with a pro-film bias.

Studios, film preservation companies, and private collectors already spend tons of money to maintain reels of old film in specially designated, climate-controlled spaces. Those same people would make just as sure that digitally archived movies remain readable forever.

Just like you can find somebody to create for you a new projector, from scratch, for your 9.5mm film, you can find an electrical engineer and a software developer who can design a playback machine and write a decoder for your digital movies. Electronics are so well-documented that it wouldn't even be that hard. It would be much more complicated, but it would get done all the same. So in the end, it doesn't matter.

A side note:
Regarding the glass plates I printed, these were not umpteenth generation copies of digital files, but the same plates the long-dead photographer loaded into his plate-holders, exposed in his camera and developed in his dark-room, and which gave me a feeling of connexion with him.
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For one, a red herring. For another, a wholly subjective psychological issue.

We're talking about movies. It's not like when you're watching projected celluloid that you're in the presence of the original negatives exposed in the camera of the cinematographer. You're watching copies of copies that have gone through innumerable hands every step of the way. Some old movies only exist as distribution prints; the original negatives have been lost. So what difference does the celluloid make compared to digital copies of movies? And what about the "feeling of connection" that one could just as easily feel when handling the original tapes or disks or computers used by the filmmakers? You might insist that it's "not the same," but the difference is only in your mind.
 
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Except in mono film, the silver halide is long gone by the time it's projected, and what you see are the organic dyes, the spectral response of which determines a lot of the look of the film. Even with bleach-bypass the dyes provide the colour look. And even with mono, the spectral response of the negative will be determined by the sensitising dyes.

Re: glass plates, we'll leave it there, since it was a side matter.

Analogue / digital / film. We can debate this till the cows come home, but the grain structure of film quantises it.

When I talk "Archival" I think "Beyond the lifespan of the youngest alive" ie 100+ years. Perhaps a drive with an unknown format with unknown data can be recovered, I'm agnostic on that, but a film negative, provided it is reasonably intact can still be recovered. Note, recovered, not necessarily projected.

Dave
 
I don't understand what you are tying to get at...

Now, film can (and does) go digital. It's called a DI. Even if you don't go through the DI process, you still telecine bringing it (the film) over to a digital format.

So, if that's your argument, cool.

If not, I have no idea what you are trying to prove.

Yes, there are dyes in film. The "blue sensitive" layer you were speaking of, is indeed on top followed by yellow and magenta. The film look is created by the "organic" alignment [or lack thereof] of the silver halide crystals. No two frames are identical in their makeup. Not just because of dye.

So really, I don't know what you are trying to get at.
 
daveswan said:
1) Film is NOT ANALOGUE.
The nearest equivalent would be with high sampling single bit audio vs low sampling multibit recording. It can only be called analogue in the sense that there is a physical representation of the scene in front of the lens left on the emulsion. But that representation is quantised, just as digital is.
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I guess my vinyl albums aren't analogue either because I'm sure that the physical structure of the vinyl doesn't literally allow for infinite variations like the original sound waves which were produced from the musical instruments.

What is the point of this thread and why is it in the 7D forum?
 
I said why it was here at the top of my post.
It was really only to voice some thoughts prompted by an earlier thread which I didn't want to hijack more than it was already.
Vinyl is analogue, since any quantisation is down to the atomic structure of the vinyl rather than the inhearent graininess of silver halide.

Dave
 
Film is analogue in the sense that a print copy is slightly degraded compared to the camera material, that's obviously true, but I'm not clear about the nature of film vs digital capture. Film grains are binary in nature; the individual light sensitive grains can only ever be exposed or not exposed, black or not-black (on or off). Surely that is digital? Whereas a digital camera's pixel site has a range of thousands of brightness levels -- and it is an analogue device, that's why you need AD converters (to transform it into digital form for storage to a memory card or record to tape). Maybe I'm wrong, maybe I need to get some sleep (been shooting all day) ... quite a range of topics you have in this 7D forum!
 
Fantastic information. One question I had about 'any film can be projected' - a great point, but is it the case that old films can stand up to projector-bright light and heat without change? I'm thinking of the way some print pigments fade badly over time.

As I had said that film was analog(ue) rather than organic, I stand corrected by this very low-level chemical perspective! This thread certainly belongs here, it's a continuation of a rather involved discussion in another thread (about 'Perya') and I don't know where else it would go.
 
Its about how its captured ,doesnt matter where its displayed,on your digital tv you have only scan of this particular copy of film stock which was captured on real film stock with emulsions and emulsion is not digital signal .
If film isnt analog then what is ?
But the real question is - is it worthy and cheaper than digital capture if outcome is very similar ?
Ive yet to see some film looks captured with hd panavision or red cams which i can compare to 90s or 80s films but it doesnt mean that 80s films are superior in overall look.
 
TrueIndigo, that's pretty much my way of thinking about film vs "digital" capture, slightly ironic given all the angst floating around :)

Incidentally, reading what Geoffry Crawley has to say in his articals for "Amateur Photographer" the Bayer pattern of most digital sensors is no more advanced than the colour separation screens dating from the 1920s, whereas the Foveon sensor is more akin to the tripack structure of colour film. Perhaps it will be the way of the future if it can be made to work well.

Eddy Robinson, hi..I think that if a film is too fragile to project, yet is of sufficient importance, then it could be carefully telecined onto digital for restoration and projection.

Cheers,
Dave
 
TrueIndigo said:
Film is analogue in the sense that a print copy is slightly degraded compared to the camera material, that's obviously true, but I'm not clear about the nature of film vs digital capture. Film grains are binary in nature; the individual light sensitive grains can only ever be exposed or not exposed, black or not-black (on or off). Surely that is digital? Whereas a digital camera's pixel site has a range of thousands of brightness levels -- and it is an analogue device, that's why you need AD converters (to transform it into digital form for storage to a memory card or record to tape). Maybe I'm wrong, maybe I need to get some sleep (been shooting all day) ... quite a range of topics you have in this 7D forum!
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Very good point.
But I think when we talk about Film vs Digital the arguements are flawed. Are we talking about the first stage of storage? Because if it is also film vs video, video is not "digital", video means the visual part of an electronic a/v signal, vhs and other forms of video tape are also analog. I think the real arguement might need to stray away from the word digital, because obviously everything starts analog (light refelcting of off objects in nature) and in our modern world everything eventually is stored and manipulated as acutal "bits" of digital information.
The crux of the arguement is film (celluloid acusition) vs video (electronic sensor acuisition). So to say something has a "digital" look. Well unless you watch an original piece of processed film you are looking at something that is very digitaly processed. Sorry I just woke up from a cat nap and thoughts are firing in my head faster than I can put em into words so that was probably really rambling. :)
 
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