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Exposure DeterminationExposure Determination



Rob, please feed this note into the telecine net - thanks.

I want to comment from Kodak about the need for feedback to
DPs on their exposure level. We have been doing a lot of work
on this and I gave a technical paper about it at SMPTE-95 in
New Orleans last month. We have three new or improved
telecine control tools which will become available shortly:

(1) Improved TAF: I know you have been waiting for this!
We are now producing this in quantity on most of the EXR
negatives, plus IP, DN, print and low-contrast print, and it
is being distributed via our regional offices. Since we trade
tested it early in the year we have further fine-tuned the
negative density aims slightly and we have a very good match
with normally-exposed film footage. This should restore
confidence in TAF since its "green" days!

(2) Gray Card: using a standard 18% gray card and gray scale
we have devised procedures for (a) determination of a normal
exposure by a DP; (b) routine exposure of gray card at the
start of each film roll or lighting change; (c) determination
of exposure by the colorist after setting up / calibrating
the telecine with Improved TAF (using primary controls only).
With TAF white set at 80 IRE (NTSC) or 610 mV (PAL), a normal
exposure of the 18% gray card falls very close to 50 IRE
(NTSC) or 480 mV (PAL) (maybe each facility will derive its
own exact level). Exposure variations have a slope of 13 IRE
(NTSC) or 56 mV (PAL) per stop, from about - 1-1/3 stop to
+ 2 stops. These procedures are given in the instructions,
which also will be distributed to colorists, of course.

(3) Telecine Transfer Evaluation Film (TTEF): a new telecine
calibration film has been developed in Europe to provide a
more accurate measure of exposure on telecine in "Transfer
Points" similar to Printer Points with which DPs are familar.
It has a range of +/- 3 stops, and also requires exposure of
a gray card, of course. I mentioned TTEF briefly in my SMPTE
paper and it will be described fully in a paper at BKSTS-95
in London this month.

Personal note: I am relocating this weekend from the telecine
suite in the Kodak Research Labs in Rochester to the Kodak
office in Hollywood and look forward to closer contact with
many of you on the west coast, as well as escaping the
Rochester winters! If there are any questions about this
note, I may not be able to respond for a few days.

Regards, Alan Masson.
Tel: (716) 477-0872 / K-25-70872;  FAX: (716)-722-7032 / K-72-27032.
INTERNET: lockovm2.zedmal at kodako.kodak.com           73 de W2/G3PSP.
Support your  SMPTE  Section and keep up with the latest technology.

--- End of forwarded message from "Alan Masson, Telecin" <LOCKOVM2.ZEDMAL at KODAKO.KODAK.COM>


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