Film-Tech Forum ARCHIVE: Proper Lamp Alignment/Bulb Focus Procedure

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Posted by Tom Wienholt (Member # 1510) on 07-08-2009, 09:29 PM:

I was doing a search on this site but could not find a procedure for properly aligning and focusing a bulb. So, what are the proper steps?

Posted by Jarret Chessell (Member # 5077) on 07-08-2009, 11:29 PM:

Assuming your lamp house is in good order....

Put your new lamp in, and manually start the projector without any film in it. You're about to put white light on the screen.
WARNING: Too much white light will wreck your lenses, if you're playing for too long close your dowser for a few minutes to let the lenses cool down.

You'll need the manual for your lamp house to see how you adjust it.

I usually start with scope format.

With white light on the screen you want to back off the focus so that you have a bright ball of light. You want to do the best you can to use the horizontal and vertical controls to get the ball of light into the center of your screen.

Once centered start using the focus control to expand the light evenly around the screen. While you're expanding the light you'll likely need to constantly adjust the horizontal and vertical controls to keep the light centered (it's fairly normal to have it try to drift out of center when backing it out).

Some projectionists like the light to be even right into the corners, others prefer having it dimmer in the corners and around the sides (because the black masking provides contrast for the eye). I'm sure lots of people on here have opinions, you can try it both ways if you like...

once you're happy with how even the light is flip to flat, you may feel you need to adjust it a little more... flip back and forth between your flat and scope until you're happy with how they both look.

Also... I usually find that after a few days when the new lamp has settled in a bit it's worth aligning it again.

I hope that helped.

Posted by Galen Murphy-Fahlgren (Member # 4535) on 07-08-2009, 11:57 PM:

Jarret's instructions are pretty good. The only things I would add are, I start focusing the lamp in the format that has the largest screen area in that auditorium (scope in fixed height, flat in fixed width), and that I don't shine the direct light through the lens for more than 10-15 seconds at a time. I follow up the alignment procedure by running a looped green band in the format with the bigger screen size, and make my final adjudication based on that. Also, check to make sure that the lamp isn't running too hot and causing buckling in your loop, which indicates too aggressive a focus.

Posted by Tom Wienholt (Member # 1510) on 07-08-2009, 11:57 PM:

Thanks for the info. However, I was referring to the method used where no lenses are in the projector during focus/alignment. What is the procedure for this method?

Posted by Scott Christopher (Member # 834) on 07-09-2009, 12:49 AM:

I think the Christie manuals explain the method you're after

Posted by Monte L Fullmer (Member # 2797) on 07-09-2009, 04:50 AM:

quote: Tom Wienholt
However, I was referring to the method used where no lenses are in the projector during focus/alignment. What is the procedure for this method?

We call that doing the "Looney Tunes" alignment - due to the fact of the rings that shows up on the screen when we get the bulb in focus - which is called the "coarse focus":

With lens and aperture out of the projector, you start the projector motor,strike the bulb and open dowser.

You'll notice the dark spot in the middle of the screen which is the bulb itself.

First you do focus which the dark spot will decrease in size along with creating the "looney tunes" ring around this dark spot. You don't want to decrease this spot too much, but back it up where the rings really show.

Then, on the dark spot, you might see "blisters" around this dark spot. This is the cathode part of the bulb coming from behind.

the goal is to hide the "blisters" which means that the bulb is square with the center of the projector.

To rid of the "blisters" is to do the lateral and vertical bulb alignments.

When you're done with this "coarse" focus, leave bulb and motor on and close dowser.

Then throw in the "scope" aperture plate and "scope" lens. Then, open dowser and you should have an even field of light over the entire screen.

If you got dark edges or a "hot spot" in the center of the screen, adjust bulb focus until the edges brighten up, or the "hot spot" is gone.. This is called "fine focus".

..BUT, be quick at this for the naked light through a lens will cook and could destroy the lens in seconds. And if using a large wattage of bulb, do this step in 15 second intervals, with having dowser closed good minute between the 15 second intervals so the lens can cool down

Good luck-Monte

Posted by Jonathan Worthing (Member # 803) on 07-09-2009, 07:07 AM:

"Looney Tunes" alignment is the way I do it & it works fine

Posted by Dan Reiter (Member # 1386) on 07-09-2009, 07:14 AM:

I too have used the concentric circles to align for years, the best way, bar none.

I wrote a procedure on this, with pictures, when I worked for Big Sky, I think it's still on thier website.

I was taught by one of the old greats, Jim Ezell.

Posted by Gordon McLeod (Member # 33) on 07-09-2009, 07:30 AM:

Even on constant width screens one must use the scope format for final alignment as this has the largest hole in the apperture per se and as such requires the flatest of field

Posted by Dennis M Dow Jr (Member # 1970) on 07-09-2009, 10:12 AM:

Dan is correct that we still have it on our website. Here is the link to the page:
Optical alignment

Posted by Victor Liorentas (Member # 5272) on 07-09-2009, 01:55 PM:

My problem is a port hole too small to get the concentric rings on screen! [Frown]

.
I end up with much of it on the booth wall around the porthole.

I also worry my reflector sits off set,how can this be verified?

Posted by Marco Giustini (Member # 4544) on 07-09-2009, 06:42 PM:

Gordon is right, always use Scope.

I agree with Jarret, but a small note: do not turn the focus knob too much, I prefer to just darken the corners and center the light this way.

Marco

Posted by Louis Bornwasser (Member # 3063) on 07-09-2009, 06:56 PM:

I just read the Big Sky alignment procedure.

While the overall thrust of this procedure is about right, it leaves out many small details. (such as critical alignment of the projector lens to the RP-40 centers and critically framing the image.)

I worked many times with the late Jim Ezell (who worked for RCA service back in the 40s-50s & 60s.) The devil is in the details; yes, it CAN be perfect.

(I'm so old, I serviced equipment for Jim Ezell's FATHER in Danville, KY. I was new and he was 86 years old back in the early 70s.) Louis

Posted by Tony Ratcliff (Member # 1196) on 07-09-2009, 08:09 PM:

I usually run the RP40 looping using the scope lens for the fine adjustment, so as not to risk damaging the lens.

I've also used a loop of the green "The Following Preview"
since it is a solid color on the whole screen.

Posted by Brad Miller (Member # 2) on 07-09-2009, 08:17 PM:

Gordon is right, always use the scope format. If scope is right, flat will be too. The type of masking has nothing to do with it.

Also, if you have to keep readjusting the horizontal and vertical adjustments as you back off on the focus, you have a physical alignment problem and are losing light.

The "Looney Tunes" method (of which I have never heard it called that before today) will also give you a good idea if your optics are properly aligned. If you can't get good circles, you need to get your tech in there. Regardless of the port window size, if you focus the lamp down enough, you will see the circles.

Posted by Jeremy Weigel (Member # 4208) on 07-09-2009, 09:13 PM:

quote: Brad Miller
Also, if you have to keep readjusting the horizontal and vertical adjustments as you back off on the focus, you have a physical alignment problem and are losing light.

Or just a poorly designed lamp house(Super Hightlight). The front mount on these causes the the vertical position of the front of the bulb to drift as you adjust the focus.

quote: Brad Miller
The "Looney Tunes" method (of which I have never heard it called that before today) will also give you a good idea if your optics are properly aligned. If you can't get good circles, you need to get your tech in there.

All my Super Highlights project warped circles/rings;even with new reflectors.

Posted by Gordon McLeod (Member # 33) on 07-10-2009, 12:15 AM:

The super highlight is a relatively good lamphouse
One must align it properly to start with then keep it so

Posted by Monte L Fullmer (Member # 2797) on 07-11-2009, 01:00 AM:

When I started working with xenon bulbs back in the early 80's with XeTron XHC-35 consoles and ORC consoles, our company tech taught me on bulb focusing and chimed in with the nick of "Looney Tunes" since the display on the screen was so similar to the Warner Bros cartoon openings.

It just stuck with me since..and I've also heard other techs also using the same nick for this procedure...

-Monte

Posted by Jarret Chessell (Member # 5077) on 07-11-2009, 02:33 AM:

This thread reminded me of something really dumb I did a few years ago...

I was in a booth where the previous people had misplaced or did who knows what with the "keys" for adjusting the lamp. I had to install a new lamp into one of the projectors and align it without the keys..... THIS WAS STUPID... AND DON'T TRY THIS AT HOME... the picture explains the rest of the story... lol

Posted by Monte L Fullmer (Member # 2797) on 07-11-2009, 02:52 AM:

I had to do basically the same with an old Christie CH-20 console with all the safeties disabled.. and the focus assembly in a dis-array of sorts:

with the DOOR OFF and bulb running (a 2k bulb): I had to adjust the lateral of the alignment by actually moving the assembly on the light table left and right to get alignment center. To do the vertial, it was reaching in close to the igniter to find the adjuster to raise and lower the back end of the bulb. To focus was the same.

I made a makeshift pair of sunglasses with taping strips of black film onto my glasses so I can see the focus through the "snood" and onto the aperture without being blinded.

Luckilly, I was behind the reflector so not to get scalded like Jarret above (and no offense, of course to Jarret..).

I'll never do that again ... The owner of that theatre had this company manager didn't know what the word "SAFETY" was and meant when he wanted me to do this task!

That was totally insane to do!

-Monte

Posted by Jarret Chessell (Member # 5077) on 07-11-2009, 12:46 PM:

I did that with a 2K bulb... unfortunately I had to lean forward to see the screen. Reaching back into the lamp house with the lamp on didn't thrill me either. I think the really bad thing about the whole deal was that I was only sun burnt on the left side of my face. [Roll Eyes]

Posted by Phil Hill (Member # 371) on 07-11-2009, 01:55 PM:

quote: Jarret Chessell
...the picture...

Hubba Hubba! [thumbsup]

Posted by Jarret Chessell (Member # 5077) on 07-11-2009, 02:05 PM:

Phil,

I really really hope that's an integrated anamorphic in your pocket....

Posted by Phil Hill (Member # 371) on 07-11-2009, 02:15 PM:

YUP! 203mm... [Wink]

(Couldn't resist ...Just yankin' your chain in a good nature...Nothing implied or expected) [Razz]

Posted by Mike Croaro (Member # 3123) on 07-13-2009, 11:48 PM:

"Some projectionists .........prefer having it dimmer in the corners and around the sides......."

Folks: You've got to be kidding. Who focuses the lamp so the center is bright and the four corners and sides are dim? This results is a poor presentation.

Mike Croaro

Posted by Monte L Fullmer (Member # 2797) on 07-14-2009, 03:21 AM:

quote: Mike Croaro
Who focuses the lamp so the center is bright and the four corners and sides are dim? This results is a poor presentation.

Unfort, this is the only way to maintain a good picture due to the way the reflector is in the console.

I saw a large complex presentation on the screen: Center was nice and bright, but you can actually see the darkness on the parameters of the screen. I asked the operator about this. He told me that the chief operator has to run it this way (they had Super Highlight II's running a 6k bulb shooting throught a PR-1050...I can get better light out of a CHR CH-45 Reference console that what that STRONG could even try to muster...) to maintain a decent picture on that huge screen.

They later went digital ....

-Monte

Posted by Gordon McLeod (Member # 33) on 07-14-2009, 07:32 AM:

Well actually the corners should measure slightly lower than the centre due to the contrast effects of the black masking
Also the gain of the screen and its geometry will determin hte flatness of field at the end of the day

Posted by Tim Reed (Member # 137) on 07-14-2009, 09:43 AM:

quote: Dan Reiter
I was taught by one of the old greats, Jim Ezell.

As good fortune would have it, Jim Ezell was the first sound man (as techs were referred to in those days) I ever met, and was the one who inspired me to enter the service field. While Louis Bornwasser graciously took me under his wing for many years and became my mentor, I never would've gotten to that point without Jim Ezell.

Jim worked for Carbons, Inc. when I first met him, and he delivered our carbon. Then he formed a service company with Don Devore (Cinema Techniques) and was our sound man... that's when I said, "Hey, THIS is what I want to do!" He outlined a curriculum for me and was a great help and inspiration over the years. Jim was the best.

Posted by Mark Gulbrandsen (Member # 72) on 07-14-2009, 10:00 AM:

I agree Tim... Jim Ezell was a great guy. It's funny that he also taught me how to properly align a lamphouse way back when Xetron was selling Prevost projectors. Jim taught me alot of stuff in the small number of times I got to work with him back in the early 80's. He is one of the few I ever knew that I would consider a really brilliant technician.

Mark

Posted by Jarret Chessell (Member # 5077) on 07-14-2009, 05:02 PM:

quote: Mike Croaro
Who focuses the lamp so the center is bright and the four corners and sides are dim? This results is a poor presentation.

I was trying to phrase my instructions carefully to avoid any arguments between members...

One easy thing to point out to make the contrast debate make sense: Most TV manufacturers use black plastic when making their sets. If you ever see a silver coloured TV you'll notice that it looks like it's producing a lower contrast. It's all an eye game, even if the guts of the TV were identical, you would still likely prefer black around the picture. I've also noticed that silver TV's often have a black band around the screen.

... sometimes you do have to sacrifice a lot of light to get it perfectly even anyways...

Posted by Justin Gorka (Member # 3727) on 07-15-2009, 02:47 PM:

Blackball? Works for me.