Conventional Fixtures Berkey-Colortran ERS Photometrics
- Thread starterSwingaxle
- Start date
My advice to you is pick up a copy of The Photometrics Handbook by Robert C. Mumm. It has all the photometric data for almost ever fixture up until 1997 (when it was published).
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Hush, Grog. Swingaxle, I stumbled across some Berkey Colortran cut sheets just yesterday. Until I get them scanned in and on my website, I hope this helps: BC_ellipsoids.pdf.
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Thank you very much gentlemen. The help is greatly appreciated. I understand that there fixtures are terrible, but my current theater has quite a few of them and we only currently use approximate photometrics. This is just an exercise in accuracy.
Sort of a necropost, but since a question in another thread was asked about these units, specifically Model#213-075...
As far as modern lamps:
Nothing is as bright as the 1000W, 300-hour FEL.
But if you're concerned about power savings, consider the long-llife 575W GLA 1500-hour lamp, or the somewhat brighter 575W GLC 300-hour. In 750W versions, the long-life is the GLE and the brighter is GLD.
About re-lensing these units; see the attached pdf file. If you have the 20° units, chances are you're missing the 4.5x9 lens and field stop to make them into 30° or 40° units.
Also included an exploded view/parts list; although don't expect to find parts available anywhere for these 1978 fixtures, but it might help with maintenance.
As far as modern lamps:
Nothing is as bright as the 1000W, 300-hour FEL.
But if you're concerned about power savings, consider the long-llife 575W GLA 1500-hour lamp, or the somewhat brighter 575W GLC 300-hour. In 750W versions, the long-life is the GLE and the brighter is GLD.
About re-lensing these units; see the attached pdf file. If you have the 20° units, chances are you're missing the 4.5x9 lens and field stop to make them into 30° or 40° units.
Also included an exploded view/parts list; although don't expect to find parts available anywhere for these 1978 fixtures, but it might help with maintenance.
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NevilleLighting
Active Member
Ah, I remember when those Berkey Colortrans were great. I'd get excited if I was going in to a venue with them. At least it is a testament to the equipment that the chassis of the units has held up long enough that your venue still has them. I do have to say that they were always a pleasure to focus although not to hang.
TheLightmaster
Member
Not for nothing, but these Colortran units were one of the best ellipsoidals for their time.
One HUGE advantage they had over everything else made here in the US was the lamp alignment system, which had a 3 sided handle, spring loaded on a large cupped washer. You twisted the handle one way for peak, the other for flat. The cupped washer allowed the filament to be angled along the access of the unit, to accommodate the less-then-precise filament design inherent in the FEL. The result was the flattest field of any ellipsoidal unit I've ever used. I wish ETC used this system today. Note that an Altman 360 and 360Q, as well as any older ellipsoidal whose lamp cap used the 3 screw plus set screw alignment system, works as well, just nowhere near as easily.
One HUGE advantage they had over everything else made here in the US was the lamp alignment system, which had a 3 sided handle, spring loaded on a large cupped washer. You twisted the handle one way for peak, the other for flat. The cupped washer allowed the filament to be angled along the access of the unit, to accommodate the less-then-precise filament design inherent in the FEL. The result was the flattest field of any ellipsoidal unit I've ever used. I wish ETC used this system today. Note that an Altman 360 and 360Q, as well as any older ellipsoidal whose lamp cap used the 3 screw plus set screw alignment system, works as well, just nowhere near as easily.
I was fabricating parts to a 10 degree a few months ago in thinking it was the last of them at work - spare parts. A few weeks ago I found an entire pallet of 5 degree fixtures Found out that I was way off in how I invented the burner assembly but it wasn't totally my fault - someone in the past countersunk four holes in the cap's corners for what I thought springs and four screws for a better bench focus. Like the way I did it better in that I don't think the central knob very good for bench focus in general. Easier and what ETC uses, yes. Takes less time yes, better I don't think so. Easier to get you roughly focused.
Possible that in addition to the center focus knob, later on Colortran did go four screw in a similar way to what might have been used on other types of fixtures? None of the above other fixtures had these countersunk holes though. Putting it out there though that a later or earlier version might have had this concept in use.
Lens trains and castings in general, wasn't very impressed with the thinness and grade of aluminum in use on them. Also kind of dislike how the lamp cap housing is mounted. Anyway, if anyone is interested in PDF'g them, I have two full sets catalogues and pricing from Colortran and Berkey Colortran that I trashed picked a few years ago. Too many other catalogues in line at the moment for me to get to.
Also noted in our fixtures that someone had driled and tapped the G-9.5 socket for a 6-32 thumb screw so as to better hold in the lamps. This feature probably didn't come from the factory though.
Glad someone is using them, want some 10 degree? (see a past sales post on them.)
Possible that in addition to the center focus knob, later on Colortran did go four screw in a similar way to what might have been used on other types of fixtures? None of the above other fixtures had these countersunk holes though. Putting it out there though that a later or earlier version might have had this concept in use.
Lens trains and castings in general, wasn't very impressed with the thinness and grade of aluminum in use on them. Also kind of dislike how the lamp cap housing is mounted. Anyway, if anyone is interested in PDF'g them, I have two full sets catalogues and pricing from Colortran and Berkey Colortran that I trashed picked a few years ago. Too many other catalogues in line at the moment for me to get to.
Also noted in our fixtures that someone had driled and tapped the G-9.5 socket for a 6-32 thumb screw so as to better hold in the lamps. This feature probably didn't come from the factory though.
Glad someone is using them, want some 10 degree? (see a past sales post on them.)
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