Film-Tech Cinema Systems
Film-Tech Forum


Post New Topic  Post A Reply
my profile | my password | register | search | faq & rules | forum home
  next oldest topic   next newest topic
» Film-Tech Forum   » Operations   » Film Handlers' Forum   » Carbon Arcs Still Available? (Page 1)

 
This topic comprises 2 pages: 1  2 
 
Author Topic: Carbon Arcs Still Available?
Andrew McCrea
Jedi Master Film Handler

Posts: 645
From: Winnipeg, Manitoba, Canada
Registered: Nov 2000


 - posted 06-23-2004 03:09 PM      Profile for Andrew McCrea   Author's Homepage   Email Andrew McCrea   Send New Private Message       Edit/Delete Post 
Hey everyone...

I didn't know Carbon Arcs were still availble. This small theatre that just burnt down outside of Winnipeg was using them up until the fire in May. The owner said in the paper that they'd go through $15 worth a night... That doesn't sound like a lot considering the cost of a Xenon.

Can any of you help me out: I want to know people who still make them, how they work and the benefits/disadvantages, etc.

Thank-you!

 |  IP: Logged

John Walsh
Film God

Posts: 2490
From: Connecticut, USA, Earth, Milky Way
Registered: Oct 1999


 - posted 06-23-2004 05:25 PM      Profile for John Walsh   Email John Walsh   Send New Private Message       Edit/Delete Post 
They are generally not avaiable. Usually, theaters that had them installed long ago continue using them.

At $15 a day, that's $450 a month. A 3K xenon bulb costs a bit more than that, but lasts several months, so xenons are cheaper to operate. When you add in the cost of cleaning a carbon arc lamp, it really doesn't make sense.

Many like the warmer 'look' of carbon arc, but for a regular theater running every day, I don't think it's worth it.

Since this has been covered before, you might want to check out the topic "Carbon Vs Xenon" from 02-08-2002.

 |  IP: Logged

Andrew McCrea
Jedi Master Film Handler

Posts: 645
From: Winnipeg, Manitoba, Canada
Registered: Nov 2000


 - posted 06-30-2004 12:13 PM      Profile for Andrew McCrea   Author's Homepage   Email Andrew McCrea   Send New Private Message       Edit/Delete Post 
In this theatre, they had 134 seats and are in a small town of about 5,000-8,000. Do you think you'd be able to determine what size xenon would be needed for an upgrade? I thought a 1.6KW would do the trick. Do you think the booth has single or three phase power?

 |  IP: Logged

Scott Norwood
Film God

Posts: 7929
From: Boston, MA. USA (1774.21 miles northeast of Dallas)
Registered: Jun 99


 - posted 06-30-2004 12:20 PM      Profile for Scott Norwood   Author's Homepage   Email Scott Norwood   Send New Private Message       Edit/Delete Post 
Depends on the screen size (we'd need to know the sizes for all formats), the lenses being used, and the screen material. The lamphouse itself will also make a difference.

What size carbons are they using now and how bright is the picture?

And, yes, carbons are available through Marble and others. I don't believe that carbon-arc lamphouses have been manufactured for cinema use for many years, although there are other applications where carbons are used. There might be some third-world country that still makes the lamphouses, though. Anyone?

 |  IP: Logged

John Pytlak
Film God

Posts: 9987
From: Rochester, NY 14650-1922
Registered: Jan 2000


 - posted 06-30-2004 12:22 PM      Profile for John Pytlak   Author's Homepage   Email John Pytlak   Send New Private Message       Edit/Delete Post 
With a matte white (gain=1) screen, the general "rule of thumb" is about 5 watts per square foot of scope screen area. So for a small 10 x 24 foot matte screen, a 1600 watt xenon lamp should easily provide enough light, as at least 1200 watts would be the "rule of thumb".

 |  IP: Logged

Andrew McCrea
Jedi Master Film Handler

Posts: 645
From: Winnipeg, Manitoba, Canada
Registered: Nov 2000


 - posted 06-30-2004 01:36 PM      Profile for Andrew McCrea   Author's Homepage   Email Andrew McCrea   Send New Private Message       Edit/Delete Post 
Here's more information:
-Booth package has been in theatre since the 1930s.
-Upgrade with Super Lume-X.
-Interested in operation of the theatre after some business college education.
-Is three phase or single phase better/cheaper when running a lamp of 1.6KW?
-10'x24'... Is that maximized in scope? I bet in a small theatre from the 20s/30s with 134 seats, the screen would be a little bigger han that.

 |  IP: Logged

Aaron Sisemore
Flaming Ribs beat Reeses Peanut Butter Cups any day!

Posts: 3061
From: Rockwall TX USA
Registered: Sep 1999


 - posted 06-30-2004 08:19 PM      Profile for Aaron Sisemore   Email Aaron Sisemore   Send New Private Message       Edit/Delete Post 
deleted double post

 |  IP: Logged

Aaron Sisemore
Flaming Ribs beat Reeses Peanut Butter Cups any day!

Posts: 3061
From: Rockwall TX USA
Registered: Sep 1999


 - posted 06-30-2004 08:19 PM      Profile for Aaron Sisemore   Email Aaron Sisemore   Send New Private Message       Edit/Delete Post 
-Booth package has been in theatre since the 1930s.

What type of projector(s) are they?

-Upgrade with Super Lume-X.

Good call. My all-time favorite xenon lamphouse.

-Is three phase or single phase better/cheaper when running a lamp of 1.6KW?

If using reactance-type supplies, three-phase is better because it is easier to filter (less ripple in the DC output with 3-phase, requiring less capacitance to accomplish the filtering). With switchers, it doesn't really matter whether you have single or 3-phase as far as the nearly-pure DC goes.

-10'x24'... Is that maximized in scope? I bet in a small theatre from the 20s/30s with 134 seats, the screen would be a little bigger han that.

That's a 2.40:1 aspect ratio, should be fine for scope- You may not be able to put a larger (width) screen in a place that old, especially if has a stage/proscenium that pre-dates CinemaScope.

-Aaron

 |  IP: Logged

Stephen Furley
Film God

Posts: 3045
From: Coulsdon, Croydon, England
Registered: May 2002


 - posted 07-04-2004 04:51 AM      Profile for Stephen Furley   Email Stephen Furley   Send New Private Message       Edit/Delete Post 
Andrew, as far as I know, carbon arcs have not been made for projection for many years. A trade magazine whiich I was reading a few years ago carried an advert for the Autoarc; I think the magazine was dated either 1970, or 1971. This was probably the last carbon arc lamphouse to be manufactured, and I suspect that it was discontinued soon after this. Xenons have been available since the '50s, but were not very widely used at that time.

Early xenons had a number of problems, including high initial cost, poor colour and tendancy to explode. Many early installations had problems with inadequate or incorrect cooling airflow, or excessive a.c. ripple from the rectifiers.

Another problem was that although xenons were introduced just after the demise of nitrate, when the fire regulations started to be relaxed to permit larger spools, most cinemas still ran film on 2000 foot reels at that time. Large spools, holding an entire film were introduced in the '60s, and platters in the early '70s. Xenons are not ideal for running 20 minute changeovers; you have to either leave both lamps running all the time, wasting power and lamp hours, or re-striike a lamp for each reel, shortening lamp life. I know of just four conversiions from xenon to carbon, three of them in public cinemas. One of these was a place that had two machines, one ran the feature from large spools on a tower, the other ran just the adverts and trailers on a 2000 foot spool. This machine was converted back to carbon for this reason; it only ran for a few minutes every 2-3 hours. This place has since closed.

Sereral changes from the 1960s favoured the conversion to xenon lamps. The use of long reels or platters made them almost essential, and at about the same time, large cinemas were being split up into several, usually three, smaller auditoria. This led to a requirement for one projectionist to operate several screens, to reduce costs. This would be difficult to do with carbons.

Carbon arcs are very expensive to operate today. The carbons themselves are expensive, and good quality ones can be difficult to obtain. Carbon arc lamps are more complex, with moving parts to feed, and in some designs rotate, the carbons; they also require frequent cleaning. Many of them also require water cooling, which xenons do not, except in the largest sizes. Carbon arcs therefore also have higher maintenance costs.

A carbon arc with a good operator, good carbons and a good rectifier or generator can produce a very steady light, but it does need looking after. Moving both carbons together, in the same direction, keeping the arc length constant, but moving it relative to the mirror by just a milimetre or two can result in a drastiic change in the brightness, colour and uniformity of the illumination on streen.

I am old enough to remember when the carbon arc was almost universal for projection; it was certainly used in all of my local cinemas. One by one, the all either converted, or closed. I could always tell as soon as the picture hit the screen that a conversion had been made, the light was different. It wasn't just that the colour temperature was higher with xenons, it was just a 'different' light. I'm not even sure what that difference is. High intensity carbon arcs emit a complex spectrum, it is a combination of a continous spectrum, and a large number of lines, from various elements in the core.

Three years ago I knew of four public cinema in England running carbons; one of those had two screens. Today, only one of those is left, I've never been there, it's a long way from where I live, and I doubt that it will last much longer.

In the U.S.A. there still seem to be just a few places running carbon, but they are converting too. The Byrd in Richmond converted not too long ago, and in the last couple of weeks, somebody here (sorry, I can't remember who it was) announced their last carbon show. There will soon be none left.

Have you ever met a steam engine enthusiast? They will talk about the difference between a steam engine and a Diesel, or an electric motor. They will tell you that a steam engine needs more looking after, but it is somehow almost 'alive', more like working with a horse than with a Diesel engine. I suppose that a carbon arc is something like a steam engine.

If you have never seen, or operated, carbon arcs, try to do so at least once, while you have the chance; they won't be there much longer, and a preserved steam engine is probably going to be easier to find than an operating preserved carbon arc.

[ 07-04-2004, 02:30 PM: Message edited by: Stephen Furley ]

 |  IP: Logged

Ken Layton
Phenomenal Film Handler

Posts: 1452
From: Olympia, Wash. USA
Registered: Sep 1999


 - posted 07-04-2004 12:05 PM      Profile for Ken Layton   Email Ken Layton   Send New Private Message       Edit/Delete Post 
Carbons are still made at www.cinemacarbons.com

 |  IP: Logged

Andrew McCrea
Jedi Master Film Handler

Posts: 645
From: Winnipeg, Manitoba, Canada
Registered: Nov 2000


 - posted 07-05-2004 03:14 PM      Profile for Andrew McCrea   Author's Homepage   Email Andrew McCrea   Send New Private Message       Edit/Delete Post 
Thanks everyone for the help!

If you were running a 1.6 KW Xenon on single phase, would it be cheaper than three phase?

Also, how do you pronounce XENON? I've always pronounced it ZEE-NIN, but do you pronounce it ZEE-NON?

Also- How do they rate carbons? Would they do it 1.6KW like a Xenon?

Thank-you once again! I've been learning so much lately

 |  IP: Logged

Stephen Furley
Film God

Posts: 3045
From: Coulsdon, Croydon, England
Registered: May 2002


 - posted 07-05-2004 04:05 PM      Profile for Stephen Furley   Email Stephen Furley   Send New Private Message       Edit/Delete Post 
Andrew, the carbons themselves are measured by diameter and length. For some reason, the diameter is usually measured in milmetres, and the length in inches. Rather than giving the power of the lamp, in Watts, it is normal to specify the current, in Amperes. My Bell and Howell 609 16mm projector burns 5.5 x 6 inch and 6.5mm x 9 inch carbons, the larger size is the positive, at 30 Amperes. This is about as small as it gets. The equivilent of a 1600W xenon might be 7mm negative and 8mm positive, at about 50-60 Amperes. The Loew's Jersey, if I remember correctly, burns 13.6mm positives, and about 9 or 10mm negatives, at about 165 Amperes. Some drive-ins went higher, I think to about 220 Amperes.

These are all 'modern' high intensity arcs, the older low intensity type used larger carbons. There were many different types of arc lamps, the most common in later days was very similar to a horizontal xenon, with a parabolic mirror wiith a hole through which the negative was fed, with the positiive poiinting towards the mirror. The length of the arc gap was typically about 6-8mm.

The 'National Carbon Buletins' are available for download somewhere in the manuals section. They give lots of information.

Here in England we pronounce xenon zen-on, while in the U.S, it tends to be zee-non. I don't know about elsewhere in the world.

Edit.

If you look at my post on the 'Seeking info on the FP-20' thread thread thread there is a picture of a machine with a typical large, water cooled, rotating positive carbon arc lamphouse.

[ 07-06-2004, 01:44 PM: Message edited by: Stephen Furley ]

 |  IP: Logged

Andrew McCrea
Jedi Master Film Handler

Posts: 645
From: Winnipeg, Manitoba, Canada
Registered: Nov 2000


 - posted 07-07-2004 08:19 PM      Profile for Andrew McCrea   Author's Homepage   Email Andrew McCrea   Send New Private Message       Edit/Delete Post 
If you were running a 1.6 KW Xenon on single phase, would it be cheaper than three phase?

Would it be smarter to do single pahse with a phase converter?

 |  IP: Logged

Aaron Sisemore
Flaming Ribs beat Reeses Peanut Butter Cups any day!

Posts: 3061
From: Rockwall TX USA
Registered: Sep 1999


 - posted 07-08-2004 02:20 AM      Profile for Aaron Sisemore   Email Aaron Sisemore   Send New Private Message       Edit/Delete Post 
quote: Andrew McCrea was the last to post
If you were running a 1.6 KW Xenon on single phase, would it be cheaper than three phase?
Price of power supplies notwithstanding, AFAIK, power is power, 1600 watts is the same whether it be single or three phase.

quote: Andrew McCrea
Would it be smarter to do single pahse with a phase converter?
If it was the motor/generator type phase converter you are wasting energy to convert the phases due to the load of the motor.

A solid-state phase converter (if such a beast actually exists) might save a few watts here and there.

-Aaron

 |  IP: Logged

John Hawkinson
Film God

Posts: 2273
From: Cambridge, MA, USA
Registered: Feb 2002


 - posted 07-10-2004 12:07 AM      Profile for John Hawkinson   Author's Homepage   Email John Hawkinson   Send New Private Message       Edit/Delete Post 
"AFAIK, power is power, 1600 watts is the same whether it be single or three phase."

Well, 1600W of output is not 1600W of input; the efficiency of the AC/DC conversion matters, and varies. I expect it depends mostly on the age of the rectifier. We all know that 3-phase rectifiers produce cleaner DC than single-phase rectifiers, but I don't know about efficiency. Anyone?

"A solid-state phase converter (if such a beast actually exists) might save a few watts here and there."

Well, such a beast would be an inverter, which certainly exists, but is probably not energy-efficient or cost-effective in the kW range...

--jhawk

 |  IP: Logged



All times are Central (GMT -6:00)
This topic comprises 2 pages: 1  2 
 
Post New Topic  Post A Reply Close Topic    Move Topic    Delete Topic    next oldest topic   next newest topic
 - Printer-friendly view of this topic
Hop To:



Powered by Infopop Corporation
UBB.classicTM 6.3.1.2

The Film-Tech Forums are designed for various members related to the cinema industry to express their opinions, viewpoints and testimonials on various products, services and events based upon speculation, personal knowledge and factual information through use, therefore all views represented here allow no liability upon the publishers of this web site and the owners of said views assume no liability for any ill will resulting from these postings. The posts made here are for educational as well as entertainment purposes and as such anyone viewing this portion of the website must accept these views as statements of the author of that opinion and agrees to release the authors from any and all liability.

© 1999-2018 Film-Tech Cinema Systems, LLC. All rights reserved.