Do you remember the 4000W xenon at 105A? Ok, it has been raised to 125 (it seems that rectifiers does not reach 135... If it so, I wonder why we bought 4000W xenon lamps).
Tonight I tried to focus the lamp.

After few tests (and a lot of sweat, perhaps I will post a shot of the booth so you can understand...), I tried to have a loop of virgin print (that is still light sensible) projected for few minutes with lamp turned on. This is the result:

As you can see the lamp ghost image is not centered in the frame. Is this normal? I never installed a lamphouse before...

Thanks for your help!!

Bye
Antonio

Using unprocessed "virgin" print film raw stock to form an image of the energy distribution at the aperture is a GREAT idea!

Looking at your sample frames, it appears that your alignment definitely is off center. The center of the light beam is about 5mm offset from the centerline of the projected image, such that the left side of your screen image will be dark. You also seem to have a "doughnut" shaped distribution of light, with a dark center, surrounded by a lighter ring. Check the distance of the lamphouse to the projector, and the focus of the lamp --- the light is being "spread out" too far.

Use the distances and alignment procedure recommended for your lamp. Other threads have described the alignment procedure using a laser alignment jig (e.g., the Alignotron made by Greg Mueller) or string, as well as the "bullseye" method for adjusting the lamp position and focus.
http://www.muellersatomics.com/alignotron.htm

Don't embarass me!

Ok, the lamp is out of alignment. But if I understand how the align procedure work (I'm moving the lamp and not the mirror), the problem can't be corrected without moving the mirror. I think that the darkest area in the sample frame is the image of the mirror. Is it correct?
If I try to adjust the lamp I'll have a bigger black center or a light "ring" more bright on a side.
I think that the bright "ring" should stay centered in the frame and then, adjusting the lamp, try to have the light ring as uniform as possible. Is it correct?

I do not understand very well your message. Are you saying that there should be no black inside the ring? Isn't it the image of the mirror?

I'm sorry if I'm not very clear...

In general, you first need to use a laser or string/rod alignment jig to be sure the center of the mirror, the nominal center of the lamp, the film aperture, and the lens mount are all in a perfect line-up, with no offset or angle (e.g., as shown in Greg Mueller's Alignotron instructions). Then be sure the mirror to aperture distance is set as specified for the lamphouse. Then put the lamp in, and use the "bullseye" technique (without the lens, to form an image of the mirror and lamp) to adjust the vertical and horizontal position of the lamp to get concentric "bulls eye" rings as you run through lamp focus. Then focus the lamp to fill the "bullseye" image with minimal dark areas. Then put in the lens and fine tune the uniformity and brightness on the screen by (hopefully minor) adjustments of vertical, horizontal and focus position. (Being careful not to overheat the lens without film to absorb most of the energy).

Your film test shows the alignment of the lamphouse to the film is likely off by about 5mm. It also shows the lamp is somewhat defocused, giving a "doughnut" light distribution with a dark center and brighter "ring" around it. Optimum lamp focus will put the brightest spot in the center, with slight falloff around it, and not a "ring". But don't "Hotspot" and burn the center of the film with too much energy!

In other words, the center of the aperture should have the brightest light, with a gradual symmetric fall off to the edges. There should be no "ring" as you now have.

------------------
John P. Pytlak, Senior Technical Specialist
Worldwide Technical Services, Entertainment Imaging
Eastman Kodak Company
Research Labs, Building 69, Room 7419
Rochester, New York, 14650-1922 USA
Tel: 716-477-5325 Cell: 716-781-4036 Fax: 716-722-7243
E-Mail: john.pytlak@kodak.com
Web site: http://www.kodak.com/go/motion

Thanks for your help. Perhaps I project the loop when the focus was not yet set. Tomorrow I will make few tests on another projector (mine!).
I saw the "align-o-tron". There weren't that photos when I saw it the last time: I'm sure it is a useful tool installing lamphouses, BUT ( ): I'm not a tech, we have paid a lot of money during these years to have a 4000W lamp driven at 105A.
My question is: let's suppose that I can adjust the focus of the lamp to have a uniform spread of light; do you think that I can correct the position of the entire light's beam operating just on LAMP controls or do you think that I need to adjust the lamphouse and/or the mirror position? In other worlds: can I shift the light beam at the center of the frame aoperating on the lamp control or not?

Your answer will be very important for me!!

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Thanks for your help. Perhaps we will change projector this summer (with an Ernemann) but if we will not change it we will start buying 3k lamp and we will align the entire system.
Now I really understand why the image on that theater has been always bad: on the gate I have the light beam shift of about 5mm, but on the screen THE LIGHT IS IN THE CENTER OF THE SCREEN. So I think that the lamphouse and the projector are completely misaligned, what do you think? Probably the lens holder are correcting it...

Gordon: you said "contact Cinemeccanica". CINEMECCANICA aligned that lamphouse. Every 6 months we have Cinemeccanica to change the lamp. In 4 years NO ONE noted that the rectifier was not able to handle a 4k lamp (also after many didodes blowed and shows canceled), no one noted that the lamphouse is completely misaligned. And they have installed 4k lamp driven at 105A for 3 years.
I'm very angry with Cinemeccanica.

It's kind of like trying to spray a stream of water from a hose through a slightly larger pipe. If the hose is aligned with the pipe, the water sprays straight through. If the water from the hose enters the pipe at an angle or off-center, it bounces around inside, and eventually some comes out the other end. But some gets sprayed back, and much of the force is diminished.

Yes, I can imagine.
I'm preparing a report for my manager. I'll include also this conversation!

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Who is Victor? I will report these facts to my manager, he will decide what to do. I hope that he will decide to take serious measures: I made approximate calculation and the result is that we wasted a LOT of money.

Today I tried with my two projectors (again two Cinemeccanica V5 with 2500W lamp).

I really don't understand how can I have on the screen a light's figure without the black ball in the center.
I turned the focus at both ends but the black ball was still present. John, did you mean that focus should be set correctly to avoid the black ball in the gate or on the screen? If your answer is "on the screen" I can't see how can I perform it.
I tried with row stock also on my projectors: I don't have the black spot in the center. The light is uniform over all the frame. Misaligning focus I had a loop of print with an hot spot in the center of the frame (so the lamphouse seems to be correctly aligned, isn't it?).
I also realized why you told me "check the distance from the lamphouse to the projector": I put a piece of paper in front of the light's beam and the black spot will reduce itself if I put the paper very near to the lens' holder/gate.

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I've already sent faxes to Milan for other problems and the only result was to have problems and discussion with our local service personnel.

I want my manager have to decide how to proceed. Eventually HE will talk with Cinemeccanica, I already have a huge discussion with them.

------------------
John P. Pytlak, Senior Technical Specialist
Worldwide Technical Services, Entertainment Imaging
Eastman Kodak Company
Research Labs, Building 69, Room 7419
Rochester, New York, 14650-1922 USA
Tel: 716-477-5325 Cell: 716-781-4036 Fax: 716-722-7243
E-Mail: john.pytlak@kodak.com
Web site: http://www.kodak.com/go/motion