Film-Tech Forum ARCHIVE: Strong X-60B lamphouse for 70mm?

This is topic Strong X-60B lamphouse for 70mm? in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.

To visit this topic, use this URL:
https://ft-forum.com/ft/cgi-bin/ubb/ultimatebb.cgi?ubb=get_topic;f=1;t=012441

Posted by Phillip Grace (Member # 2262) on 06-11-2019, 05:02 PM:

Hi all.
Does anybody know how to configure a Strong X-60B Lamphouse for 70mm? I'm trying to discover how to adjust the spot size for the 70mm aperture. Is it just a matter of adjusting the lamp focus, or is there supposed to be a change of reflector, or addition of a spreader lens? There are manuals for the C and D models in the warehouse, but unfortunately not the B. (I could also use some new reflectors for 35mm projection).
Any advice will be more than welcome.
Thanks.

Posted by Dave Macaulay (Member # 813) on 06-11-2019, 07:44 PM:

The B version is almost identical to the C, the changes are mostly electrical as I recall (B is 220V?). You add a beam expander lens for 70mm in a dual format installation, it is also a UV filter. A metal box thing screwed to the front of the lamphouse to hold either a UV filter plate or the beam expander. For dedicated 70mm use I think you could change the distance to the aperture... and maybe just a lamp position change would suffice. For high power lamps with the metal collector, the UV filter is recommended as without it the film color bleaches out pretty quickly. Probably not an issue (if film was still used) with current releases lasting a week or two but when a movie could play for many weeks, prints would get badly faded. Since presumably you want to show archive prints (what else is there?) you should have a UV filter.
Naturally those Strong filters and expanders are NLA, but maybe BLS or someone still has some.

Posted by Gordon McLeod (Member # 33) on 06-12-2019, 10:12 AM:

I actually found i had more light just defocusing the lamp than with the beam spreader

Posted by Phillip Grace (Member # 2262) on 06-13-2019, 08:22 PM:

Thanks Dave and Gordon for your advice.
The pair of X-60B's I am using has a housing for a drop-in lens attached to the front of the snood. It does look well made, but probably locally, not OEM. The spreaders, if any, are long gone. The reflectors are glass cold-light type. I'll have a play around with lamp focus and lamphouse position when there is an opportunity. I've be told of a number of situations where defocusing the lamp was the preferred method, even if the spreader lenses were available. Will also investigate a UV filter to protect the film. Fortunately 70mm screenings will be quite some time into the future, not "later today" - the way the 35mm was scheduled.
Thanks again for your help.

Posted by Phillip Grace (Member # 2262) on 06-23-2019, 10:31 PM:

Supplementary question. Does anybody know where the vane switches are located in the X-60B? I cant see anything obvious - unlike the 60-C where the vane switch is mounted directly under the exhaust stack.