Film-Tech Forum ARCHIVE: Tracking SRD on badly printed prints

This is topic Tracking SRD on badly printed prints in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.

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Posted by David Graham Rose (Member # 1450) on 07-07-2003, 03:01 PM:

Greetings from Cambridge to you all.

Many of the theatres that I use to evaluate my research groups' innovations have recently complained about the widespread deficiency in correctly printed SRD tracks. The problem, in the majority of instances is with a particular reel's SRD track being printed out of alignment.

I have recently examined a number of prints that have faulty tracks, and apart from those where the printer exposure time and thus the track density was incorrect, have found that the lateral displacement varied too greatly for the projectors CCD to catch the corners.

To this end my team and I have modified a number of projector manufacturers readers.

We have developed a method that has proved 99% reliable in tracking print errors*(ref.1). The system comprises of miniature motors on all 4 edges of the card holding the CCD array. Using a programmed PIC connected to the ouptuts of the cat. 673's (or cat. 773 in a CP650) we have been able to adjust for deficiencies in lateral and azimuth positions of the data block as encountered in release prints.

We hope to develop a commercial system utilising data transmitted via the serial output of a DA20/CP500/CP650 by the end of the year.

In addition to this system, and to coincide with the launch of the Dolby cat. 702, we are also aiming to automatically adjust the gain control of the LED, in order that data tracking remains at an optimum.

The prototype system that we have developed includes an audible warning for the projectionist which sounds as roughly 2 months before the end of the LED's life, to ensure that the digital subsection does not 'fail hard'.

I should be interested to hear from anyone who has any suggestions which may inprove this system.

Ref 1. Rose, Platt, Davies and Anthony et al. Acta Cinematografia Vol 99. 22, p34-36 'Reduction In Tracking Errors In Release Prints'

From Cambridge, good afternoon.

David

Posted by Michael Schaffer (Member # 1204) on 07-07-2003, 03:05 PM:

That sounds like a great idea, but I would rather have the distributors improve their QC and give us better prints than have us invest in yet another piece of equipment. If the print is good, the Dolby reader works very well.

Posted by David Graham Rose (Member # 1450) on 07-07-2003, 03:24 PM:

Yes indeed Michael.

You have posted at quite an excellent moment. I am currently giving a tutorial on SRD tracking to my postgraduate group. We have just had a 'hands up' on whether QC vs 'digital always-whatever' and I am afraid to report that my tutees would rather have digital on all reels rather than relying on the QC at the lab.

I do believe that I have a group of realists in my study this evening!! Could this be a first?

With another hot toddy, I wish you all a good night.

David

Posted by David Stambaugh (Member # 1102) on 07-07-2003, 03:53 PM:

Sounds like a good idea to me. [Big Grin]

Posted earlier

That thread pertained to DTS, but the same principle applies to the other digital formats too.