Looking Brighter Now!

[Jim Cassedy]

Ok- - sorry for the semi- teaser topic.

>> Last weekend I put a pair of brand new reflectors in the 35/70
JJ lamphouse consoles. (STRONG Highlight II's , w/ 4k Xenon blubs)

NuReflector.jpg

The old reflectors were in pretty bad shape, esp the one in Proj
# 1, in which the reflective surface was flaking off like party glitter!
ReflectorGlitter.jpg

Unfortunately, I didn't think to take "before & after" light measurements with
my lumenocitor- - but visually, I can see there's been a great improvement!

Replacing those reflectors was definitely the brightest thing I did all week!

[Sean McKinnon]

Awesome! I am glad these worked out for you.

[Mark Gulbrandsen]

Reflectors are getting hard to get. You may want to double check your airflow... Could have been a defective reflector, I had that happen with those reflectors before where the coating flakes off. Poor airflow can cause a similar peeling issue, sometimes with the addition of metal burn marks.

[Jim Cassedy]

<edited>Reflectors are getting hard to get. You may want to double check your airflow...

And expensive too! - - I don't know the complete provenance of these machines, only that
they were installed here somewhere around 2019, long before I became head house tech,
for "Once Upon A Time In Hollywood", and on opening night they had the main bearing fail
in one of them- on he same proj with the lousy lamphouse- - so maybe it wasn't well cared
for before we acquired it. I spoke with a couple of well known cinema suppliers at the
Telluride Film Festival last fall, and one of them told me that he's seen this problem before,
and that, yes, it could be heat related, but he also said it also wasn't all that uncommon for
reflectors 'of a certain vintage' to have the silvering start flaking off even if well cared for.
Overheating was also my first thought too when I started noticing the flaking issue late last
fall. Even though I knew we have a pretty robust booth exhaust system here, I brought in
my Suck-0-Meter™️ and confirmed that we were well within the exhaust CFM
specifications for the size bulb we were using according to the lamphouse manual.

The Suck-0-Meter, (also known in some
circles as a Blowometer)
AirFloMeter.jpg

[Leo Enticknap]

I recently had a "looking brighter, now" moment, too. This was in a mixed use venue that, thanks to the absence of a fly tower, has to use a roll-up screen for movie shows. We installed an SP2K-9, which the math suggested should light the screen with around 2ft-l of headroom at 90% laser power. The problem was that it didn't: I only got 12.2 with the light maxed out.

After some head scratching, we formed the theory that the very old screen, which must now be into negative gain territory, was absorbing a lot more light than we'd factored in. Replacing the screen is on their roadmap, but as they are a small nonprofit with limited funds, cannot be done immediately. So this was the solution we came up with:

image.png

That hole gave us about a 4 ft-l light boost! The booth is high enough above the seating and the projector is quiet enough such that you can't hear anything at all from the auditorium, as long as no-one is having a party in the booth while a movie is playing.

[Mark Gulbrandsen]

I actually have a light transmittance meter that I use, and have used it over about a 15 year period. I found the transmittance of glass used in typical booths had a transmittance of from 78 to 92 percent. The lower end was the usual double strength window glass but I discovered that some "white water" glass was nothing to write home about as well. The best was actually Schneider AR glass, or 1/4 inch Plexi. Of course I would never install Plexi since it scratches all by itself just from looking at it cross eyed. Anyway, I also found that quite a bit of plexi had been installed in various theaters, that was all replaced, as was much of the common window glass.

In Leo's case, I'd cut the hole slightly larger and then silicone a piece of Schneider glass in it. That will stop the back and forth movement of air, and dust through the hole at zero and keep the lens clean. I have done this in theaters a number of times that had huge port windows and that saves a ton of money.

BTW, my meter came from a State of Utah surplus shop, it was still not cheap... it came with a standard piece of calibration glass so I can verify it before taking measurements...

[Tony Bandiera Jr]

Ok- - sorry for the semi- teaser topic.

>> Last weekend I put a pair of brand new reflectors in the 35/70
JJ lamphouse consoles. (STRONG Highlight II's , w/ 4k Xenon blubs)

NuReflector.jpg

The old reflectors were in pretty bad shape, esp the one in Proj
# 1, in which the reflective surface was flaking off like party glitter!
ReflectorGlitter.jpg

Unfortunately, I didn't think to take "before & after" light measurements with
my lumenocitor- - but visually, I can see there's been a great improvement!

Replacing those reflectors was definitely the brightest thing I did all week!

My # 2 machine at the university had that same glitter flake issue, thanks to the building BMS shutting down the projector exhaust fans without warning. That started a huge interdepartment battle with lots of finger pointing as to who should pay for the replacement reflector. It never got resolved even after I left.

[Mark Gulbrandsen]

Nothing more hilarious than an interdepartment battle! We had one at the TV station regarding who should pay for the new 120k dollar Klystron tube that failed in the transmitter... This battle had a good outcome though... It all went to court, and Varian got stuck with the entire tab instead any of the TV station departments.

[Tony Bandiera Jr]

Nothing more hilarious than an interdepartment battle! We had one at the TV station regarding who should pay for the new 120k dollar Klystron tube that failed in the transmitter... This battle had a good outcome though... It all went to court, and Varian got stuck with the entire tab instead any of the TV station departments.

Yeah the one thing I absolutely hated about that gig was the departmental BS. In the early years of my tenure the dept. head was experienced in those things and all ran smoothly. After she moved on, it gradually went downhill, the last few years were a nightmare.