Telecine is Dead!

Telecine is Dead!

Moore's law in computing performance and storage capacity has made the traditional telecine film transfer model obsolete.

In recent years, the film transfer process has transitioned from the use of traditional telecine equipment (e.g. Spirit, Cintel) that outputs only video, to modern film scanners (e.g. ScanStation, Director, ARRISCAN, etc.) that output digital files in a variety of formats.  A transition driven by the increasing quality of image scanning technology coupled with an explosive growth in computing power and storage capacity.

Telecine Image Quality is Inferior to Scanners

Real-time scanning was required in the old days when the only viable image "pipe" was a real-time video channel. In those days, everything had to be sacrificed for speed. As a result, telecines generated real-time video at the expense of noisy and highly unstable images (all telecines are edge-guided which causes extensive weaving).

With the advent of the Digital Intermediate (DI) process, the low quality output of the telecines was replaced with the dramatically higher quality output of DI scanners (e.g. the Lasergraphics Director, ARRISCAN, Northlight, etc.).  These scanners do not need to output real-time video.  Instead, they generate data files.  As a result, these scanners can take the time to generate significantly superior images that are very low-noise and extremely stable.

For example, the Northlight scans at less than 1 frame per second, the ARRISCAN scans at rates ranging from 4 to 8 frames per second, and the Lasergraphics Director scans up to 15 frames per second. The reason for this non-real-time scanning speed is simply this: QUALITY.

Telecine Images are Unstable

All telecines use the edge of the film to keep it registered in the gate.  This practice is called “edge-guiding”.

Film aligned to edgeImage sensor aperture

Typical telecine gate

However, motion picture cameras do not use the edge of the film while exposing.  Instead, they use the film perforations.  The spacing between the edge of the film and the perforations is not well controlled by film manufacturers.  The SMPTE 93-2005 specification for 35mm film dimensions allows for a margin of ±2 mils between the perforations and the edge.  This corresponds to an error of ±4 pixels at 2K resolution.

Film scanners that directly use the perforations of the film to align each frame separately improve alignment accuracy to approximately 1/5 of one 2K pixel.  This represents an improvement in stability of over 20 times compared to edge-guided telecines and telecine-like scanners.
Pins

Mechanical pin registration is great for new film but bad for damaged or shrunken film.

More modern film scanners use optical pin registration to stabilize the image.   Film registration is achieved by optically sensing one or more perforations as a guide.


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Lasergraphics' proprietary 2D optical pin registration system locates up to 8 perforations and is able to register the frame even if only one of the perforations is usable.  The frame is stabilized in the X, Y, and rotation axes.  Therefore, shrunken film can be effectively stabilized with no mechanical or software adjustments.  All optical pin registration is performed during the scanning process, eliminating the need for any post-processing.

Lasergraphics scanners are highly immune to perforation damage and splices while maintaining registration.  Lasergraphics' 2D optical pin registration detects the location of all of the holes and then determines which ones are damaged.  The damaged ones are ignored while the undamaged ones are used to align the image.

Optical pin registration is superior to:
  • mechanical pin registration, which engages the film in only two perforations and is only effective on undamaged and unshrunken film.
  • edge guiding, which weaves laterally because it entirely ignores the holes and is highly intolerant of splices.

Telecines are Splice Intolerant 


Edge-guided telecines and film scanners can not handle splices well.  Splices cause a lateral shift in the image position when they touch the edge guide, which in turn creates lateral color shifts in the image.
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Optical pin registration eliminates the film registration problems caused by film splices.
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Telecine Images are Susceptable to Banding 


Telecines and telecine-like scanners move the film continuously past a thin aperture, corresponding to its line image sensor.  As a result, dirt builds up in the line aperture during scanning.  The dirt that accumulates in the scanning aperture blocks some of the light in subsequent frames.  This causes subtle intensity differences which appear as banding in the image.
For area imagers, this dirt typically remains outside of the active image area because the scanning aperture is oversized.

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For modern film scanners, this dirt typically remains outside of the active image area because the scanning aperture is oversized.

Telecines can't Detect and Eliminate Dust


Film scanned on a telecine invariably contains dust in some frames and has no means of automatically detecting or eliminating these defects.

The Director film scanner incorporates infrared dust and scratch detection which works during scanning to detect and reduce dust and surface scratches without softening, blurring, or altering the image. A defect matte is generated, depicting pixels that have been automatically corrected and defects that require additional attention (if any). The defect matte allows the uncorrected defects to be easily located and addressed in post.


Telecines can't handle Warped Film

Telecine Film Gate

Doesn't lay flat resulting in bad focus
The Director Film Gate

Warped film held flat on 4 sides with pressure plate for superior full-frame uniform focus

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Scan comparison between the Spirit 4K and The Director demonstrating warped film tolerance of a 1940's era 35mm nitrate film. Notice the ripple effect on the Spirit 4K scan. The Director is immune to this problem because the film is held flat on 4 sides with a pressure plate.

Summary


Telecine

Scanning

Multiple passes (lo-res for dailies, hi-res for final edit, grading and effects). Single hi-res pass for HD dailies, final edit, grading and effects.
Film handled twice, increasing chance of damage. Film handled once, reducing chance of damage.
Poor film registration (edge-guided.). Film aligned digitally.
Images noisy due to lack of light. Plenty of light for low-noise images.
Periodically generates stripped images due to dirt accumulation. Dirt accumulation, if any, occurs outside of image area.
Incapable of detecting and eliminating dirt. Detection and reduction of dust and surface scratches without softening, blurring, or altering the image.
Poor warped film tolerance. Very good warped film tolerance.
Complex and costly video equipment, operators and gurus. Easy-to-use, low-cost, off-the-shelf PC equipment without need for experienced operators or gurus.
Linear workflow wastes resources and time. Non-linear workflow maximizes resources and saves time.