[Tig] Oxberry scanners
sai at efxmagic.com
Wed Nov 29 01:12:09 GMT 2006
Well with respect to colorimetry and faithfully translating the 'analog'
data off OCN and recording them out, I have yet to come across a scanner
manufacturer that will actually guarantee that. They all 'say' that we can
create Lut's and all that fancy talk which really means you need "color
scientist" to do some kind of magic. And even then, just scanning a
particular OCN emulsion and recording it straight out has never given us the
exact densities (after DMIN has been subtracted)when compared to the OCN. If
there is someone out there who has actually done that .. I'm sure he will
not be willing to share it. just goes to say that there is still a lot of
talk without any simple solution a manufacturer can provide. With new
emulsions , different labs, recorder drift, makes it harder if not
Having said that ... what most manufacturers do is just give us a standard
LUT and leave the rest to us operators to figure out. What most of us do is
try to capture as much of the dynamic range as possible and adjust the
images digitally so that when recorded they will look good on film.
Most film recorders also provide you the ability to record a full range
cineon file as apposed to a 95-685 point setting.
Coming to think of it, remember that all scanners are linear devices. So the
conversion to Log happens downstream. So you can set it up anyway you like.
Why not use more CV's to achieve a look instead of restricting it to 95-685
and leaving the rest for head room.
I think I have confused myself even more now than before ... ;-)
sai at efxmagic.com
p.s. I'm not upto speed on current developments. If there is something I am
missing, please please let me know.
From: tig-bounces at tig.colorist.org [mailto:tig-bounces at tig.colorist.org] On
Behalf Of Chris Swinbanks
Sent: Tuesday, November 28, 2006 4:28 PM
To: Jason Crump
Cc: tig at colorist.org
Subject: Re: [Tig] Oxberry scanners
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A question, did you output each of the tests to film again?
Generically film recorders are based on utilising Cineon/DPX code values
so that the circular relationship from o'neg to digital neg is
maintained (dynamic range / contrast, colorimetry).
Breaking that by changing the dynamic range of scanned material as
described here opens up a can of worms for down-the-line production
Unless of course you're staying in a broadcast environment....
Jason Crump wrote:
> re: calibration/setup and density/code value relationship:
> By looking at the scans, I think i can assume that most of the
> scanners were
> "setup" by sampling base and then incrementally assigning code values
> on the densities of the layers as per cineon. This effectively meant
> all of the code values were between 95 and 685 with some specular
> jumping above 685. This was true for all expect the Oxberry. Oxberry
> spread the same densities among a wider range of code values. So base was
> around 50 and the specular highlights were in the 900's and the mid-tones
> were much more spread out in between.
> I can only assume that the scans whose visible black of base showed code
> values roughly around 95, were as per cineon. However, since we did
> not scan
> density steps from d-min to d-max on an OCN, I don't know whether the
> density values from d-min to d-max were properly assigned their
> corresponding code values as per cineon.
> Although the oxberry scan looked brighter than all the other scans, I
> that because the code values were more spread out, I had much more
> color to
> play with and much more flexibility to push and pull these colors. I
> know the exact sensor specifications of these machines, but it seemed
> from photon to code value, I liked the oxberry the best. Is it as per
> cineon?... I don't think so. Is that a bad thing, if the results offer
> flexibility and dynamic range?... nope. Is this the result of a custom
> by the facility?... probably. Can it be achieved on the other
> scanners?... i
> don't know.
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