[tig] tig:Cyan Dye Tracks

Peter Swinson peter_swinson
Thu Sep 30 18:24:07 BST 2004


With regard to this thread I will place these comments for what they are
worth.

Jim Mann suggests using the Aaton/Evertz head to also detect the track.
These days the delay needed would not be an issue I guess. However, and
isn't there always a however, the film at the keycode reader location is
not running as stable as at the capstan. Film twist, perf slap and guide
roller eccentricity, due to dirt or manufacturer tolerances will all, I
believe,  introduce significant amounts of wow  and primarily flutter if
the sound is picked up at the keycode reader location.
Now I suppose that some bright spark might suggest also reading the film
perfs to correct the audio for speed errors at this location, but it then
starts to get really complicated. PLUS, keycode can withstand some defocus,
certainly more than would be wise for picking up the HF of an analog track.

Regarding fitting RED Leds or similar at the existing head.
I don't think I am speaking out of turn when I say that I did look at this
issue at Cintel several years ago, before Cyan Tracks were even expected to
be adopted.
At that time a pretty powerful red source was required to get any
sensitivity out of the system. The existing lamphouse would not accomodate
such a red light source.
The alternative was to adapt a projector cyan track reader system. This
would have involved fitting the light source into the capstan groove. Again
size was an issue, but even more problematic was the heat generated by the
light source, it would locally heat the capstan which could distort it.
When stopped the capstan could "cook" at the point where the lamp was
mounted causing  a bump in the capstan. 
Both methods, requiring more lamp power could cause film damage when the
film was stopped, not a condition that occurs in Film Piojectors,

I suppose further design that killed the lamp when the scanner was stopped
could be included,  As could other film transport stabilisation methods for
reading at the keycode head, but I just wanted to indicate that the
solution may not be as simple as has been suggested.

However please, please, keep coming up with suggestions, on this and other
topics, because as I know so well, it is easy for manufacturers not to see
the trees for the forest when thinking of solutions to problems.

best regards

Peter Swinson
Peter Swinson Associates Limited





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