8mm Forum: Taking the mystery out of... XENON LAMPS

This is topic Taking the mystery out of... XENON LAMPS in forum 8mm Forum at 8mm Forum.

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Posted by Jan Bister (Member # 332) on September 04, 2005, 10:44 PM:

Maybe I'm getting spoiled... [Big Grin]

but I swear, sometimes the EFR bulb in my ST-1200HD just doesn't cut it, even with a Schneider 1.2 lens and a Da-Lite projection screen (projected image size about 5.5ft to 6ft wide)... I thought about putting in a 250W/24V ELC bulb with an external power supply but am also thinking about just going the xenon route instead.

I know nothing about how xenon lamps work, though - what kind of power supplies they require, what their heat generation is, how they differ in usage and operation from regular halogen bulbs. I only know they last a lot longer (and are a lot more expensive). Neither do I want to melt the film - or, God forbid, the gate - due to insufficient cooling. [Wink]

Help an old fool like me take some of the mystery away and understand all I need to know...

Posted by John Clancy (Member # 49) on September 05, 2005, 01:35 AM:

Try doing a search for HTI on this forum. Ugo's done several postings about his HTI lamp conversions. That will be a good starting point.

Posted by Jan Bister (Member # 332) on September 05, 2005, 04:28 AM:

Does that mean xenon = HTI? Whoops, I thought HTI was yet something entirely different. Anyway, doing a search now, thanks. [Smile]

Hours later...

Wow, 194 search results... a lot of info. And a lot of confusion, still... Maybe I'm better off just picking up a 16mm projector with a 24V/250W power supply for parts, and using a 250W ELC bulb in my Elmo... That really should do it...

Must admit, though, it's my recent screening of two Roger Rabbit cartoons (which have perfect color and immense density - blacks are truly black) that had me scratching my head over the light output... most of my other super-8 films are old and have various degrees of fade... hence less density, and they look brighter on the screen. [Roll Eyes]

[ September 05, 2005, 06:14 AM: Message edited by: Jan Bister ]

Posted by John Clancy (Member # 49) on September 05, 2005, 09:01 AM:

The HTI xenon/arc lamp gives a brighter light output than the standard Elmo GS-1200 Xenon. Wittner's sell a kit that they claim can fit any projector. Of course the truth is somewhat different as their lamp holder doesn't even fit a GS-1200 but it is possible to modify it (apparently). HTI lamps only cost £180 and I believe last up to 300 hours.

Ugo's modified a couple of machines and has detailed this in some of the posts your search will have found.

[ September 09, 2005, 08:15 AM: Message edited by: John Clancy ]

Posted by Ugo Grassi (Member # 139) on September 09, 2005, 06:55 AM:

Dear Jan, the Xenon lamps and the HTI lamps are in the same family: that one of the "discharge lamps". The difference is for the gas inside the bulb: Xenon or (HTI) metal vapors.
Both the lamps work in the same way.

Posted by Kevin Faulkner (Member # 6) on September 09, 2005, 07:56 AM:

Ugo, am I correct in saying that the xenon lamp is a colder light output than the HTI?

Kev.

Posted by Ugo Grassi (Member # 139) on September 09, 2005, 09:19 AM:

The XBO lamps have a color temperature of 6000°K. The HTI w32/250 (that's right for the super 8) gives 5600°k. But there are others HTI lamps able to arrive to 6300°K.

Posted by Steven Sigel (Member # 21) on September 09, 2005, 10:32 AM:

John Clancy said:
"HTI lamps only cost £180 and I believe last up to 300 hours."

Only £180 ?? Sounds pretty darned expensive to me. That's 60 pence per hour (unless of course you really meant 3000 hours, which would be another story)...

You can get a Xenon lamp for the GS-1200 from Superior Quartz Products for about $200 (£110) and it's rated for 2000 hours. That's about 6 pence per hour - a factor of 10 times cheaper...

To Jan:

Hand mofifying a projector is a big job and will not be cheap...

If you want to go the 250W route - you might consider buying a GS-1200... (I've got two of them here :-))

Posted by John Clancy (Member # 49) on September 09, 2005, 11:00 AM:

Fair point Steven but it's cheap when you consider the Gemini lamp is around £100 and lasts 50 hours. The Superior Quartz lamp is very cheap but reports advise the brightness is not up to the original. No surprise there really and I'm sure we're all extremely grateful it's available - the bloke behind it deserves a medal. Given that the HTI gives reportedly brighter output than the original xenon lamp, by my reckoning £180 is good value.

Also, there are no longer any genuine ESC lamps available for the standard GS (except those I'm having off you!!!) so with comparatively poor light output compared to what we enjoyed before, the HTI conversion gives the equivalent life of 5 or 6 EJL's but substantially improved brightness.

Depends how you look at it really.

Bill Parsons has done an experimental conversion of my GS (previously had the Gemini 300 lamp - still widely available, but the power supply was trashed) and has never seen a picture like it from a GS. I can't wait to see it myself. The idea behind this conversion being to use it at the 50th BFCC but obviously we'll have to test it thoroughly in the short time available to us before 22nd October.

Posted by Steven Sigel (Member # 21) on September 09, 2005, 02:17 PM:

Hi John,

I'm pretty much out of super 8 now, so I haven't compared all the various options. How much does an HTI conversion cost? Figure a Xenon GS-1200 is worth about $2500 or thereabouts and a non-xenon GS-1200 is about $1000-$1500...

In 16mm, I only use Xenon - halogen lamps just don't cut it for me... I guess I've been spoiled by the xenons.... I wouldn't touch MARC - it's just too darned expensive (although you can get the Gemini lamps in the US for a lot cheaper than 100 quid). It's still really expensive to run... MARC also has a problem with consistency - they get dimmer as the lamps get older...

(Oh, and FYI - I was the one who had Superior make the clone lamps for the GS-1200 Xenon, along with some help from Ian O'Reilley (who provided me with a lamp to send them) and Alan Gouger (who did the testing when the lamps arrived)) :-)

Posted by Jan Bister (Member # 332) on September 09, 2005, 06:44 PM:

Thanks for all the advice (and interesting facts on the side). [Smile]

Steven - you're right, it would make more sense to upgrade to a GS1200 than to equip an ST-1200HD with a xenon or HTI lamp. [Eek!]

As for going the 250W (halogen) route... since the point has been sufficiently driven home by now that a GS1200 will only reliably run a 200W bulb, I'm not quite sure how one would use a 250W bulb in it except by means of an external (more powerful) transformer? [Confused]

Posted by John Clancy (Member # 49) on September 13, 2005, 01:44 AM:

Steven, I knew it was down to you we have the Xenon lamps available again. I was pullin' yer leg. The medal's in the post.

The HTI kit from Wittner's costs about £650. If you can do the conversion yourself it's pretty cheap but I doubt there's many people who can work around that hash of a kit. Bill Parsons really stuck to the task with this conversion and a medal's in the post to him too.

Posted by Alan Rik (Member # 73) on September 14, 2005, 01:44 AM:

Yes! Now we are getting somewhere! If Bill can tell us how to do the upgrade that would be fantastic! Bill...are you out there? [Smile]

Posted by John Clancy (Member # 49) on September 14, 2005, 10:42 AM:

Doesn't look like this is a DIY job given the kit Wittner's have flogged me. Bill has really had to use all his know how to pull this one off. But we're hoping to put some sort of an article together in the future dependent on how well (and reliably) the machine performs.

Posted by Alessandro Machi (Member # 461) on September 16, 2005, 02:25 AM:

If it's possible to safely modify a projector for xenon projection, that could possibly make an interesting article for Small Format Magazine, although I don't have any influence over the stories they do, I would find it interesting.

I had a chance to use an Elmo Xenon Projector when I attended college a while back. We used to fill a small theatre with a large screen that was at least 15 feet high. We put on several super-8 film festivals back in the mid-late 80's.

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