[Tig] Measuring a DCI-theatre projector - new vs old lamp

John Tissavary jt at traktionfilms.com
Fri Mar 1 15:32:55 GMT 2013


Color temp will not change with Xenon DCI / DLP projector bulb replacement,
but light level will for sure.  There are power and on some projectors iris
settings that allow for compensation... but do theaters measure light
levels regularly?  Some projectors have blub-wear profiles that allow for
automatic compensation, but that's just based on known bulb life and not
necessarily as accurate as measuring and stopping down the power.

John

John Tissavary
owner | colorist | e.p.

<http://www.lunacie.com/>


On Fri, Mar 1, 2013 at 6:06 AM, Ken Robinson <flight4 at gmail.com> wrote:

> Sohonet www.sohonet.co.uk sponsors the TIG.
> Support from Digital Vision www.digitalvision.tv
> =====
>
> Hi Carl,
>
> I cant really comment on DCP projectors, but I can regarding Spirit. The
> whole point of that machine and its feedback loop was that if you changed
> the lamp within the correct time, colour temp never changed.... Well at
> least for me! The only time I had a problem was when I turned up somewhere
> as a freelance, didnt check the lamp hours, started grading wondering why I
> couldnt see through the film very well.... Some hours into the grade I
> decided to have a look at the lamp hours... 4000+, so changed the lamp, and
> everything came back! The exposure was so different that I dont remember if
> temp changed or not.
>
> Ken
>
>
> Ken Robinson
>
>
> On 1 March 2013 05:49, Carl Skaff <carl at stopp.se> wrote:
>
> > Sohonet www.sohonet.co.uk sponsors the TIG.
> > Support from Digital Vision www.digitalvision.tv
> > =====
> >
> > I just know from working on a spirit classic.... If the lamp died in the
> > middle of a grade it wasn't fun. A brand new lamp vs an almost dead lamp
> > had a very different temperature. Although that could usually easily be
> > adjusted with the sprit primaries.
> >
> >
> >
> >
> > /Carl
> >
> >
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