The document discusses the history and development of frame rates in film and video. It begins by explaining the phi phenomenon and how early silent films found that 12 fps was perceived as motion by the human brain. It then details how sound film standardized at 24 fps to synchronize with the audio track. Television developed interlaced formats like 60i to conserve bandwidth and avoid flicker given its technical limitations. Over time, color standards like NTSC in North America incorporated techniques like 3:2 pulldown to convert 24 fps film to the video standards. Higher frame rates have been experimented with but have not replaced 24 fps as the standard for narrative film.

1. HISTORY OF FRAME RATE
What is the Phi Phenomenon?
First described by Max Wertheimer (1912), nothing in the movies are real,
from set to actors, even the essence of moving pictures. It is all an optical
illusion. The spinning circle of wheel isn’t actually moving but instead the dots
are taken of one by one and put back again and when the process speeds up it
looks as if the circle is moving around.
What is the significance of 12fps?
The human brain can perceive about 10-12 individual fps. Faster than that
our brains blend the images together into motion. Playing back 12 frames per
second with 12 intermittent period of black as the film advances it will create
an intolerable amount of flicker. In order to make the flicker disappear, and
according to Thomas Edison the magic number is 46 times per second.
What is over and under-cranking?
The inconsistency of silent film frame rates was a hassle for historians and
preservationists. Early cameras and projectors were hand cranked and
cinematographers will under-crank and over-crank the camera for effect.
Under-crank: Recording a slower frame rate than final projection, and over-
crank: recording a faster frame rate than final projection. D.W. Griffith was
notorious for under-cranking his shots, shooting as low as 12fps. Even Edison
ignored his own recommendation.
What impact did the introduction of sound have on frame rate?
The introduction of sound was one of the most drastic technological and artistic changes in all of motion
picture history. Since sound was recorded as an optical track that ran alongside the film strip, recording and
playing back film had to be kept at a very strict and even frame rate. That frame rate would be established
internationally in 1929 as 24 frames per second. However, the need for a consistent24 frames per second
was a major problem in the sound department. The first sound cameras with their whirling electric motors
were very noisy- forcing camera operator to shoot from a soundproof booth through a window.

2. Give as much rationale as you can for why 24 became the international frame rate
standard?
They found that the audio track just didn’t have enough fidelity on a 16 frames per second system. Utilizing
48 projected frames as our goal, they stepped up the next factor, utilizing a 24fps projection utilizing a
double bladed shutter to keep to desired 48 projected frames per second. 24 is a number that can be easily
divided by 2,3,4,6 and 8. So an editor can know right off the bad that half a second is 12 frames, A third is 8
frames, a quarter is 6 frames etc. It isn’t cheap and 24 frames was just the lowest easily divisible number
that would work for sound. It is almost culturally ingrained into what we come to expect from the cinematic
experience.
What issues surrounded bandwidth?
Television had the same problem, flicker issues that plagued motion picture film- yet flashing the same
frame on screen was not an option that was technologically achievable. Engineers were more concerned
about bandwidth, something they were trying to keep hold of over-the-air television broadcast. The solution
was developed solely by German Telefunken engineer Fritz Schroter in 1930 and in the US by RCS
engineer Randall C. Ballard in 1932. To conserve bandwidth and avoid flickering- each frame would be
interlaced.
What is interlacing?
Interlace is summarised into 2 fields- an upper and a lower field. Each field would be created on the screen
one after the other in a comb like patters. After the scan returns to the top and repeats (now scanning the
even lines), the two fields are then woven back together to make a full-frame image, hence the name
interlaced. It is also known as the letter “I” (as in 60i or 1080i), was picked for a lot of technical reasons that
have very little in relation to how we watch and shoot television today. The outcome of this decision left us
with a very crisp image that is laid down in an alternating order. Tis time the lines are scanned 1,3,5,7,9, etc.
into what is called a field. It reaches the bottom of the frame in half the time, meaning that if something is
moving very fast across the screen, interlaced will deliver a crispier picture, very much similar to a fast
shutter speed on a still camera.
How was the challenge of intermodulation tackled?
In order to beat the distortion caused by hum generated in the electrical current, the refresh rate was set to
that of the AC power- in the US, 60 Hertz- so that each field is created in a 60th of a second resulting in a
full 30 frames per second
To demolish intermodulation, which is the beating distortion caused by hum generated in the electrical
current. The refresh rate was set to that of the AC power- in the US, 60 hertz so that each field is created in a
60th of second resulting in a full 30 frames per second.
What is the significance of 60 Hertz and how does it relate to 30 frames per second?
A game’s frame rate is distinct from the screen it’s being exhibited on. Displays tend to acquire their own
frequency: the “refresh rate”, or how often the device (for instance, a TV or monitor) refreshes its screen;
this is counted in hertz (Hz), where 1 Hz is one cycle per second. Several modern TVs and monitors have a
refresh rate of 60 Hz, meaning that the optimal situation is for an image source (for example, a game console
or Blu-ray player) to come in with a frame rate that evenly divides into 60. A standard TV refreshing at 60
Hz would go through all 60 frames of a 60fps feed in a single second one frame every one-sixtieth of a
second. The same TV would show each of the 30 frames in a 30fps feed twice every one-thirtieth of a
second.

3. What is the difference between VHF and UHF?
In 1948, the Federal Communications Commission (FCC) places a moratorium on a new television
broadcast licenses as it tried to figure out what to do with the newly available UHF spectrum. The idea was
to introduce a new colour system using a higher frequency bandwidth and let the older VHF channels which
the older tv sets that could access die off. While they were trying to figure out what to do, TV sales went
through the roof exploding from 1 million sets to just over 10 million in a matter of a few years. In the end,
the idea of letting older VHF TV stations die off became impractical. The race to create a colour standard
that was compatible with older black and white tv sets.
 VHF- 30-300 MHz
 UHF- 300-3,000 MHz
How was a colour standard arrived at?
The National Television System Committee (NTSC) created the 1st US TV standards, reconvened with RCA
leading the way utilizing a system first introduced by Georges Valensi in 1938. Breaking the image down
into luminance and chrominance, broadcasters could embed a colour signal as a subcarrier in the television
signal. New colour TVs could pick up and interpret this colour subcarrier which is ignored by the older
black and white TV sets, however there was one other problem.
What challenge did bandwidth present to achieving a colourstandard and how was this
problem overcome?
The bandwidth used by the colour subcarrier could potentially interfere with the audio signal causing
intermodular beating. The solution was to decrease the frame rate by a factor of .1% phasing the colour and
audio signals this prevents them from fully matching up.

4. What was the fields per second ratio that was eventually developed as the standard in
colour and what was the resulting frames per second ratio?
December 1953, FCC adopted the RCA system for colour broadcast and we go from 60fps, down to 59.94
fps – for an effective 29.97 full frame per second. In a mathematically ingenious way of creating a signal for
both colour and black and white television sets, we have these odd ball frame rates that are still a big part of
modern broadcasting standards. However, this is only if you live in a country that utilizes the NTSC
standard.
What is PAL and why was it developed?
1963 German television manufacturer Telefunken released PAL to the European broadcasting union with
regular broadcasts in PAL starting in 1967. PAL was a format designed to solve the colour problems that
plagued NTSC and would work with the 50hertz AC power used in Europe and elsewhere in the world.
What are the fields per second and frames per second ratios of PAL and SECAM?
PAL along with similar format SECAM run at 50i for an effective 25 fps.
a) Produce a step-by-step guide to explain how we get from the 24 frames per second of film to a 60i
video stream to be able to watch celluloid movies on video.
b) What are the issues with the various conversions?
First the 24fps film is slowed down by 0.1% giving us 23.976 frames per second. You need to make 4
frames of 23.976 fit into 5 frames of 29.97. Do this by splitting up the frames into field using a 3:2
pulldown. The first frame is captured onto three fields – the upper, lower and then upper field- that’s one
and one-half frames. Then the next frame is captured on the following 2 fields, lower field and then upper.
The next frame fills up the lower, then following upper and lower with the last frame filling the upper and
lower. So, having 3 fields, 2 fields, 3 fields, 2 fields. Thar’s the 3:2, 3:2 cadence. Unfortunately, this
procedure isn’t perfect with resulting video stream having Telecine Judders every 3 frames which is
specifically noticeable on long slow camera movements.
How do modern digital cameras avoid the telecine process and with what effect?
Reverse Telecine or Reverse 3:2 pulldown are technologies that work backgrounds, constructing a 23.976 or
24p video stream from the 3:2 pulldown 60i footage. Most modern digital cameras can avoid the telecine
process altogether and record 23.976 or straight 24 frame rates natively onto the hard drive, however, there
are some workflows that run video through HDMI cables which are rated for 60i (limitation put on the
camera), may still utilize the 3:2 pull down.
How are 24fps films telecine’d onto SECAM or PAL 25 fps?
For telecining film onto PAL or SECAM’s 25 fps, the procedure is much simpler. Utilizing a 2:2 pulldown,
the 24 frames per second footage is sped up 4% and each frame is transferred onto two fields- an upper and
lower field. This amplified speed raises the pitch of the audio by a noticeable 0.679 semitones or a little
more than a quarter step musically, yet can adjust down using a pitch shifter.

5. Explain high frame rates and temporal resolution and What are the issues with higher
frame rates in narrative filmmaking?
24 frames have been the standard for narrative film for nearly a century now. However, enterprising
filmmakers have tried to push the temporal resolution or frame rate higher- trying to decrease motion blur to
create smoother and more realistic look. One of the notable experiment in high frame rate is Showscan- a
70mm format developed by Visual Effects Wizard Douglas Trumbull who’s famous for developing many f
the visual effects for Stanley Kubrick’s 2001: Space Odyssey. Running at 60 fps, Showscan created a
stronger biometric response in test audiences, yet the process was never found use in narrative film- being
utilized mostly in motion simulator rides.
More recently, Trumbull has worked on a Digital Showscan shooting at 120fps and adjusting the play back
anywhere from 24 to 120 frames depending on the needs of the shot. Though, audiences just haven’t been
warm to high frame rate in narrative film- the most recent experiment was Peter Jackson’s “The Hobbit”
presented in 48 frames per second. Variety reviewed the film and complained that the “human actors seemed
over lit and amplified” in a way that many compared to modern sports broadcasts or daytime television. One
projectionist complained that “It looked like a made-for-TV movie”. Nevertheless, filmmakers at the
technological bleeding edge, for instance, peter Jackson or James Cameron, still push for higher frame rates.
So, the question now is that “Will the future of narrative filmmaking leave 24p behind?” The technology is
already here, the new 4K standard are capable of up to 120 frames per second. While these high frame rates
may be great for recreating the immediacy of sports broadcasts or really good 3D or for video games to this
filmmaker there’s just something cinematic about the cadence of 24 frames per second. For all its drawbacks
in clarity and motion blur it’s just how we grew up watching movies. Maybe the next generation will grow
up high frame rates and see 60p the new cinematic look, or perhaps not. Frame rate is engine behind the
cinematic lie- the magic trick that allows us to enter a world that is not quite real but real enough. A simple
defining number shaped by psychology, economics and clever engineering all in service to the act of telling
stories.
BIBLIOGRAPHIES
 The History of Frame Rate for Film. (2015). [film] Directed by J. Hess. Filmmaker IQ.
 Reff, M. (2008). Choosing Your Direction: Progressive or Interlaced. [online] Videomaker.com. Available at:
https://www.videomaker.com/article/f6/13755-choosing-your-direction-progressive-or-interlaced [Accessed
19 May 2017].
 Sarkar, S. (2014). Why frame rate and resolution matter: A graphicsprimer. [online] Polygon. Available at:
https://www.polygon.com/2014/6/5/5761780/frame-rate-resolution-graphics-primer-ps4-xbox-one [Accessed
19 May 2017].