> Dirk Bruere at Neopax <dirk.bru***@gmail.com> writes:
>
>>Anyone know the lumen output of the projector? I know the o/p of the light
>>source, 15kW 600k lumens, but not the machine itself.
>
>
> Under what conditions?  During projection, the light output depends on
> the content of the film, since the film absorbs most of the light
> reaching the film plane.
>
> The open-gate light output would be much higher, but you can't actually
> run an IMAX projector open gate for more than a few seconds without
> risking cracking the projection lens (thermal effects).
>
> Also, what are you comparing to?  The screen image in an IMAX theatre is
> going to be pretty dim compared to a home theatre, but the IMAX theatre
> is completely dark while the home theatre generally is not.

> Dave Martindale wrote:
>
> > Dirk Bruere at Neopax <dirk.bru***@gmail.com> writes:
> >
> >>Anyone know the lumen output of the projector? I know the o/p of the light
> >>source, 15kW 600k lumens, but not the machine itself.
> >
> >
> > Under what conditions?  During projection, the light output depends on
> > the content of the film, since the film absorbs most of the light
> > reaching the film plane.
> >
> > The open-gate light output would be much higher, but you can't actually
> > run an IMAX projector open gate for more than a few seconds without
> > risking cracking the projection lens (thermal effects).
> >
> > Also, what are you comparing to?  The screen image in an IMAX theatre is
> > going to be pretty dim compared to a home theatre, but the IMAX theatre
> > is completely dark while the home theatre generally is not.
>
> I'm comparing it to home digital video projectors that say things like "2000
> lumens" on the box. So I assume that's open gate.
>
> So far I have had to make an educated guess that approx 20% of the bulb's
light
> gets to the screen (in both cases).

> Dave Martindale wrote:
>
> > Dirk Bruere at Neopax <dirk.bru***@gmail.com> writes:
> >
> >>Anyone know the lumen output of the projector? I know the o/p of the light
> >>source, 15kW 600k lumens, but not the machine itself.
> >
> >
> > Under what conditions?  During projection, the light output depends on
> > the content of the film, since the film absorbs most of the light
> > reaching the film plane.
> >
> > The open-gate light output would be much higher, but you can't actually
> > run an IMAX projector open gate for more than a few seconds without
> > risking cracking the projection lens (thermal effects).
> >
> > Also, what are you comparing to?  The screen image in an IMAX theatre is
> > going to be pretty dim compared to a home theatre, but the IMAX theatre
> > is completely dark while the home theatre generally is not.
>
> I'm comparing it to home digital video projectors that say things like "2000
> lumens" on the box. So I assume that's open gate.
>
> So far I have had to make an educated guess that approx 20% of the bulb's
light
> gets to the screen (in both cases).