Thinking about aspect ratio

Carl Looper · February 20, 2015

I'd add that the cinema projector decodes a representation of experience by not only adding time (real time) between each frame of film in a film strip, but also removing the space that otherwise separates each frame in a film strip.

Adding time and removing space.

The reverse operation, would be encoding. So one might say the camera encodes a representation of experience by removing time between the frames of the film stock, and adding space (supplying filmstock).

Removing time?

Yes. The first photograph is a long exposure photograph. I recall it was a nine hour exposure. In any case a long time. What follows in photography is a decrease in exposure times. One might call this "removing time". The goal is a better expression of things in space. Intentionally or otherwise. Otherwise moving figures become more visible. They take on sharper outlines. What had been at best blurry ghosts in empty streets emerge as more solid apparitions. The shape of people (and horses etc) start to populate the space of photography. Clamps will otherwise be used to hold subjects in place. Photography is evolving towards the snapshot. Towards an instant in time one might say. Not zero time for such is impossible - in theory and practice. But shorter intervals of time. Towards the moment.

What photography loses in terms of time, it acquires in terms of space.

It will be cinema that arrives to give time back to photography. To insert time between the Muybridge snapshots, and remove the space.

C

Carl Looper · February 22, 2015

Chronological time.

This is a concept of time used quite often in cinema, including time travel movies. It is based on a model of time in which there is a past, a present, and a future. Often this will be transformed through concepts of memory, precognition, flash-back, flash-forward, bullet time, etc, but the framework will tend to remain intact.

There is the concept of a dividing line, a single instant of time, between the past and the future, called the present. Bullet time explores the concept of such an instant, where we (in observer time) can otherwise move around in space, while world time stands still, so to speak.

The concept of persistence of vision is based on the assumption of a dividing line. Given such an assumption we can find ourselves asking how we can experience (perceive) movement if a previous frame didn't somehow "persist" (for example, in memory) into the next frame.

However we can question this assumption of a precise dividing line between the past and the future, in both the observed and the observer. We can suggest that there is a minimum duration beyond which one can not pose a shorter duration, let alone a zero duration. We can suggest the past and the future can not be cleanly divided. A bit like Hawking radiation where the dividing line between outside and inside a black hole is fundamentally blurry (leading to Black hole evaporation).

The following explores this concept.

We can ask what is the minimum duration, a physical film projector can insert, between frames in a film. Is it zero?

The speed of light represents a physical speed limit. This speed limit © is:

c = 299 792 458 m / s

This limit means a physical film projector would have a maximum frame rate at which it could physically operate, beyond which it could not go any faster. For a 16mm film projector, by way of an arbitrary example, the maximum frame rate would be determined by the film's pitch (p), which is:

p = 7.62 mm

The maximum frame rate (f) becomes the speed of light divided by the film pitch ( f = c/ p ):

f = c / p

= 299 792 458 000 mm / 7.62 mm

= 3.934 e10 fps

The minimum interval (t) between each frame is the reciprocal of the maximum frame rate ( t = 1/f ):

t = 1/f

= 2.542 e-11 secs

If we projected Super8 film, we could could make the interval shorter (reciprocally the frame rate higher). But we can't add a zero interval between the frames. Mathematically there would be a division by zero error somewhere in the computation, or a violation of the speed limit.

The general concept here (rightly or wrongly) is that a single instant in time (a diving line) is a fiction of sorts.

C

Dennis Couzin · February 23, 2015

Carl's latest post is quite wrong. It borrows ideas from Special Relativity, including light's velocity being the maximum, without following though. The denial of there being an exact moment dividing past and future is Special Relativity's denial of simultaneity. But I still am waiting for anyone who understands Special Relativity and also understands cinema to make any lucid analogy. Calculating that 16mm frames can't be transported in less than 2.542 e-11 seconds doesn't cut it. It says nothing about cinema, and nothing about time.

The concept of persistence of vision is based on the assumption of a dividing line. Given such an assumption we can find ourselves asking how we can experience (perceive) movement if a previous frame didn't somehow "persist" (for example, in memory) into the next frame.

The concept of persistence of vision is NOT based on the assumption of exact moments dividing past and future. Time could be quantized and then persistence of vision could be expressed as gaps of a single quantum or more being invisible. Indeed persistence of vision means that a high Hz flickering light appears constant. (It is why 24 fps projectors need two-bladed, or better three-bladed shutters.) Cinematic motion perception is something completely different. First described by Wertheimer's Phi Phenomenon, it requires a first still image and a second still image at definitely distinct times. Then what one perceives is a motion carrying the first image into the second image. The phenomenon requires that the two times not be too close. There's no fine dividing line presumed.

I can't follow Carl's reasoning about space or time in cinema, especially when they're described as being in competition.

Cinema is a temporal art, and cinematographers have temporal skills to match this. How good are the films of great still photographers? But also, how good are the still photographs of great cinematographers? The temporal skills aren't easily added, or subtracted.

The durational aspects of cinema are more the work of editors.

There is one funny place where space and time do compete: in video bitrate. One must sometimes decide between making, for example, 1280x720 60p or 1920x1080 24p -- two Blu-ray options with similar bit rates, there being no 1920x1080 60p option. Assuming that one is not hooked on the 24p cinema look, this comes to a choice between temporal smoothness and spatial smoothness. It's an aesthetic decision in which philosophy, physics, etc. have nothing to say.

Edited February 23, 2015 by Dennis Couzin

Carl Looper · February 23, 2015

Persistence of vision and the phi phenomena are two different theories.

While both attempt to explain more or less the same thing they take a different approach in terms of their explanations and assumptions.

"The denial of there being an exact moment dividing past and future is Special Relativity's denial of simultaneity."

My denial is not this denial. While Special Relativity certainly denies simultaneity it's through comparison of different frames of reference. For a single frame of reference (as I'm postulating) special relativity doesn't immediately provide for any denial of a exact dividing line between past and future. Indeed it is quite suggestive that there would be an exact diving line.

I'm not interpreting (or misinterpreting) Special Relativity. I'm posing an additional concept.

C

Carl Looper · February 23, 2015

Space and time can be understood as capable of co-operating with each other as much as competing with each other.

It boils down to the concept of difference.

Time expresses difference, but not just those differences that can be measured or represented in terms of space (hyperspace), but also those which can't.

For example we can express, in terms of space (colour space), the difference between red and green. We can measure or define the difference in terms of such a space. We can spread out in 3D space all possible colours according to whichever model we like. We can specify a vector, between two points, in such a space, where one point represents red and the other green. We could express the difference between red and green in terms of the magnitude (distance) of the vector between red and green. Or in a lot of other ways as well.

But in what space could we possibly express the difference between, say, turquoise and eating?

We would not, due to lack of any common space, suggest there were no difference. On the contrary we would suggest there is far more difference, between turquoise and eating, than there is between red and green.

Indeed so different, is this kind of difference, we could define this kind of difference as a very different type of difference. And if we did manage to find any common ground, as a way of providing for an answer, we would no longer be entertaining the kind of difference we are otherwise entertaining here. We will have succeeded in excluding such difference.

One is a difference in terms of a common framework. The other is a very different type of difference.

Now the real question here is what is the difference between these two types of differences? The answer is that the difference belongs to the second type.

We are able to experience this difference. To feel this difference. It is not a difference that escapes our senses. But it is a difference which escapes a spatial solution.

It is this type of difference that we are aiming to engineer. The kind of difference there is between turquoise and eating.

The proposal is that time, more so than space, provides for the expression of this difference.

But that's not to say space is incapable. The work of Surrealist photo-collage is a good counter example.

C

Dennis Couzin · February 23, 2015

Persistence of vision and the phi phenomena are two different theories.

While both attempt to explain more or less the same thing they take a different approach in terms of their explanations and assumptions.

Every student of cinema should know that what persistence of vision explains is completely different from what the Phi Phenomenon explains. They have only to consider that the projector requires a 2- or 3-blade shutter to reduce flicker because our persistence of vision is too short for projection with a 1-blade shutter, while this has almost no effect on our perception of motion because the number of frames per second remains 24.

Persistence of vision is well understood. D. H Kelly (of Technicolor!) did excellent research in the 1960s and 1970s along with many others. The small residual flicker in movie projection contributes to the film aesthetic.

Motion perception in cinema is poorly understood. There has been no solid research since Wertheimer's from 1912. It's of great importance for cinema. Besides practical questions like shutter angle, there is now an aesthetic divide between the 24 fps folks and the 50 or 60 fps folks, which might be swept away by the no-fixed-frame-rate folks.

Carl Looper · February 23, 2015

Persistence of vision is an answer to the question of motion perception.

It proposes that an image, no longer in the present, persists in order to connect with a new image in the present..

It is not just in relation to the cinema, but in relation to natural perception as well.

Phi theory reposes the question, for which persistence of vision is the candidate answer. It reposes it as a candidate answer to question regarding flicker.

The question here is not whether persistance of vision answers it's question (that of motion perception), or answers any other question for that matter, but rather: what are the assumptions that produce this answer in the first place (let alone second place).

In the same way one might investigate the assumptions that produce the concept of the aether. It is not a question of whether the aether is the correct solution to a certain class of problems - it is a question of understanding the concept and how it came about in the first place.

History.

C

Dennis Couzin · February 23, 2015

Why all this muddle? Reading too much French philosophy? What else produces such a slather of questions, proposals, candidate answers, assumptions, concepts, concepts, and more concepts? There can be no science in that truthlessness.