Film-Tech Forum ARCHIVE: Proper lamphouse alignment... or???

This is topic Proper lamphouse alignment... or??? in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.

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Posted by Jack Ondracek (Member # 1466) on 01-27-2004, 11:40 PM:

OK... where am I going wrong.. or???

I have one screen with an Ultra-80. It has what looks like a good reflector. It's positoned right, distance-wise, and is aligned with the world-famous "Align-O-Tron". It lights an SA/TA. In the same theatre, I have 3 Super Lume-X's, 2 of them with new reflectors. They're all running behing PRO-35's.

Bulbs are either new, or are well within initial warranty.

I have taken advantage of all manufacturers' instructions I can find, from Strong's "string" method to Greg's super-advanced laser pointer.

Still, I seem to have an ongoing challenge, keeping the middle of the screen from looking a lot hotter than the sides... quite a bit more so with the "ulra", but also to a lesser extent with the lume-x's.

I notice this on the features, but I see it more on things like trailer rating strips, which have, as far as I know, a relatively uniform colored background (green).

I'm wondering what I might be missing, since I've been to a few theatres across the water from me that have more uniform illumination than I seem to be getting.

Bulb focus doesn't seem to matter much... the hotter center is pretty much uniform relative to the sides, regardless.

I understand that when using measurement devices the sides aren't expected to rise to the level of the center, but I get the impression my setup is somewhat more noticeable... at least to me.

Posted by Brad Miller (Member # 2) on 01-28-2004, 12:25 AM:

You've got the same complaint I have about Strong lamphouses. I haven't ever seen one that I've been happy with...meaning, without that hotspot. From the sound of it, you have things optimized as best as it will ever get. (Next time buy a Christie SLC.)

I have heard people say that a layered wire mesh can be installed in place of a beam spreader, being more dense in the center, but so far nobody has been able to offer any specific information on sizing and such.

Posted by Peter Mork (Member # 1336) on 01-28-2004, 01:49 AM:

I wouldn't depend on trailer rating strips, or any print for that matter, to be reliable for checking illumination. I've seem many that had hot spots of their own. A test film or a loop of painted leader would be better.

I like the Strong lamphouses - but whenever the tech guy sets them by the book, I always have to tweak the settings. Sometimes chucking out the rules and going by instinct is the best policy. Smiley face.

Posted by Michael Schaffer (Member # 1204) on 01-28-2004, 03:51 AM:

As unlikely as it seems that Brad and I can agree on something, I also find it very difficult to get really uniform illumination without the hotspot from Strong lamphouses. And I have also align-o-troned those lamphouses, checked the projector head position, taken measurements with a light meter.
However, I also have my little problems with the SLC consoles, especially with the motorized focus. When you move the lamp along the focus axis, it often looses its horizontal or vertical position. That makes good alignment a little tricky. Sometimes the motorized assemblies fail, then you are in for a lot of fun. I like the Christie rectifiers though.
Best if you get a Kinoton lamphouse, then you get an efficient, even light output with a lamp 1 size down from competing products, and you also get a really massive solid focus assembly where you can ram your allen keys in, focus the lamp within 15 seconds, and which also keeps that focus.

Posted by Brad Miller (Member # 2) on 01-28-2004, 04:10 AM:

Michael, just an FYI, you can get the SLC without the motorized focus option and use allen keys for the alignment.

I'm going to have to play with Kinoton lamphouses a bit more before I make a firm statement one way or the other regarding which I feel is the better choice. Indeed they are the only other lamphouse on the market that truly puts out a good light other than the SLC. The SLCs have been extremely good to me. They just keep on running happily year after year and the xenon lifespan on them is incredible. It doesn't take a rocket scientist to do the math on actual $$$ between an SLC and something from a competing company. Even if the SLCs are a thousand or two more than another lamphouse, the savings in operating costs more than makes up for it.

Posted by Matt Zeiner (Member # 1914) on 01-28-2004, 07:21 AM:

quote:
Bulb focus doesn't seem to matter much... the hotter center is pretty much uniform relative to the sides, regardless.

I have not had any really noticeable problem with the Lume-x except when some tech decides to jumper out the failsafes in them - the reflectors seem to be easily damaged by heat - often undetectable unless you look at the "target" patterns (without the lens). I always get good, reasonably flat light out of them. With the lens in, do the corners pull in uniformly as you focus/defocus the bulb? Are you running on a matte screen or "gain" type?

Posted by Gordon McLeod (Member # 33) on 01-28-2004, 09:31 AM:

I think matt may have hit the key word screen gain
what type of screen do you have. If there is always a hotspot and the focus only changes the relative brilliance not the ratio of the hot spot then it is usually the gain of the screen that is in question

Posted by Greg Mueller (Member # 17) on 01-28-2004, 09:48 AM:

When I did my Super Lume X, I found that I got more even illumination by defocusing it. I too had that hot spot and as I ran some film I just adjusted the focus on the back of the lamphouse until the illumination flattened out. It might be different if you need every watt on the screen but in my case I had power to burn (from the improved alignment) so defocusing wasn't an issue. I just got it to where it was the most pleasing and called it good. I'm using a Hurly Super Glo screen. Can't remember the gain

Posted by Phil Blake (Member # 2012) on 01-28-2004, 11:18 AM:

I guess the lamphouse is properly aligned with the projector head ???

Focus will be hard to achieve if it is not.

Posted by Jack Ondracek (Member # 1466) on 01-28-2004, 11:24 AM:

Thanks for the input!
I've heard these things about Strongs... though I don't recall the issue being that noticeable with my old X60b/glass reflector!

The really wierd thing was that the hotspot I had at my drive-in totally disappeared when I replaced the U-80 with a Big Sky 7kW lamphouse.

Anyhow... thanks again for the input. I guess I'll keep at it until I have a bunch of $$$ laying around and nothing to spend it on except some new lamphouses! [Cool]

Oh... my screens are nothing special... which means I don't know exactly what they are! They're basically the stuff Act III (pre-Regal) was using. I'll get back there & take a look.

Posted by John Pytlak (Member # 331) on 01-28-2004, 11:46 AM:

If the screens are gain screens, they should be properly curved per SMPTE Recommended Practice RP95 to reflect the projector's light back to the center of the audience, ideally by ray tracing. You can verify the proper curve by holding a mirror PARALLEL to the screen's surface at various points, and verifying that the light is reflected to the center of the audience.

Posted by Michael Schaffer (Member # 1204) on 01-28-2004, 03:15 PM:

You will probably find a sticker on the back of the screen identifying manufacturer and dimensions. The manufacturers usually put it into on of the lower corners, though the riggers sometimes hang the screen so that the sticker is in one of the upper corners...

Posted by Justin West (Member # 920) on 01-12-2005, 10:02 PM:

I am looking for a source of one of those string-type Strong lamphouse alignment kits...for my Lumex lamphouses...I believe it is the same one that is used on the Super Lumex. Can anyone direct me to potential sources? Thanks!

Also, while I am posting, what distributor sells the Splycemar splicer? [Confused]

Posted by Richard May (Member # 2627) on 01-13-2005, 08:45 AM:

Brad. I have four X-90 consoles in the booth. Three of them always had very evenly distributed light across the screen. 16 in the center down to 15 at the sides as measured with a meter. I changed the reflector last year on the fourth one and that one has the hot spot problem. I aligned it twice and still no good. I wonder if it's a problem with the new reflectors from Strong. Most of the Super Lumex lamphouses that I have dealt with in the past with the original reflectors have not had an issue. Only when I changed the reflector was there an issue.

Posted by Monte L Fullmer (Member # 2797) on 01-14-2005, 04:57 AM:

..also, I'm Playing with 5 locations with ALL of them having those X-90 consoles-a total of 32 of them. With some built back in the late 80's and new ones built in '99.

...and I've having this "hot spot"/even field of light problem in almost all of them, esp the old ones.

Now, my big question, or wonderment is that (we acquired these locations about 3 yrs ago) if the bulb was set too far back in the mirror to where the mirror got too hot and slightly distorted the rear of the mirror causing this "hot spot"/focusing problem that we seem to hear about?

Yes,I've actually replace one mirror being that the old one was badly distorted due to excessive heat. Plus, the design of the mirror entraping too much heat, for as we know of these older X-90's (without that muffin fan in the front) with their somewhat weak air supply to cool down the ends of the bulb and move air around in a whole.

Yep. Christie SLC and Reference consoles are the way to go. Large mirror, not to much in a conical shape, lots of air flow from behind the mirror to cool things down real well, (and with a Reference console with that separate blower to cool down the anode when burning 6k bulbs) and a very sharp even field of light on the screen.

...and we all had manual mirror adjustments that used that long 9/64 allen key. Didn't believe in motorized adjustments.

-Monte

Posted by Ian Bailey (Member # 1752) on 01-14-2005, 05:49 AM:

Hi Jack
I had the same problem with my Super Lume-x untill I changed from Osram to Ushio xenons.The first Ushio I put in I had to wind the focus knob quite a bit to make the lamp move forward and bingo absolutely beautiful even spread of light on the screen.I can't wait to change the Osram in my other Super.
The only thing is I don't understand why,unless the Ushio has a different focal point (or something) compared to the Osram.

Posted by Tim Reed (Member # 137) on 01-14-2005, 10:20 AM:

Anyone have a Lumex alignment kit for Justin?