ERS reflector question

Doesn't seem as if the photos were on a new reflector and delivered from the factory that way, but instead something found on-site and already installed into a fixture. If the case, no doubt what better way to vent a fixture than destroy the optics of it by way of drilling holes in the reflector for venting? Perhaps a moot point in asking - something seen, something somebody did and something one should not be doing if one really understands the fixture? Perhaps these were 1Kw lamped fixtures that were burning thru sockets and it was an amature idea on how best to improve the venting on them so as to preserve the incorrect lamp running too hot for the fixture.

Interesting, not seen this before but have seen the old style TP-22 socket drilled and tapped and fitted with a thumb screw so as to retain the lamp better - no doubt during the same era of 1Kw FEL lamps needed to be used. And yes, both "upgrades' do date back to the Super Reflector days.

If the case that this is the "new" super reflector, please confirm this info and I will contact my sources at Altman and get the answer.

On the other hand, in re-viewing the second photo for the "lantern" in question, what brand is it? I don't know what it is either. Above concept in drilling holes in a reflecor for cooling probably still apply.
 
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I didn't see a reason for the extra holes in that link. There was also a lot more bad info in there. They must have super tough hands too if they think you can touch a 100 watt incandescent bulb after being on for hours without burning yourself too.

it said the holes were a solution to the lamp itself casting a shadow, which was solved by making reflectors with a lamp mounted straight in
 
The Radial had the lamp mounted at an angle which meant that the lamp
actually cast a shadow in the beam. While not noticeable in normal use, it
also put a hole in the side of the reflector, leading to less than optimum
light output. The Axial fixed this problem by having the lamp mounted
straight in, eliminating the shadow and moving the hole where it mattered
less. However, both these types have their problems and require a lot of
maintenance to keep running.

This paragraph doesn't explain multiple holes. It says the older non axial fixtures had a shadow from the lamp due to the hole in the side of the reflector where the lamp was. Then that that problem wasn't an issue anymore when they introduced the axial fixtures since the hole was in the center of the reflector, and not the side. It may be possible that the holes somehow helped with a shadow problem but this document does nothing to give us an answer one way or the other.
 
techieman33 is correct; this article is more a description of the large elongated hole for the actual lamp. I will also agree that there is a bit of misinformation sprinkled about -- I wouldn't necessarily say that both types of fixtures "require a lot of maintenance to keep running". Keep your bench focus as optimum as possible, change the lamp socket every decade or so (in heavy use), and maybe replace a shutter blade here or there... That's really about it.

Just a bit of trivia for the younger guys: To follow up on what was left out of the article above, the reason for the non-axial lamp was because the huge incandescent lamps had to be burned as close to base-up as possible. I've heard a few reasons for this, and they're probably all somewhat correct. One being that the filament supports would fail when turned at an extreme angle, and another suggesting that since there was no halogen cycle, the black deposits from the filament could gather near the lamp base rather than on the globe where it would more interfere with the output.
 
To add to what Les said about BBU lamps, I understand that since it is a lensed fixture, the beam is inverted and since the hole for the lamp causes dark areas of the beam, it is better to have the dark areas fall on the floor rather than on the face. Another pre-Halogen cycle bit of trivia, many lamps had (I think) granules of sand in the bulb so you could shake the lamps like maracas to remove some of the black buildup and extend the life of the lamp.
 
See I've just heard something else from someone I know. Mr Jim Laws - Strand expert in the UK and has loads of strand (and other older) lighting kit. Including a Light Organ from Drury Lane Theatre! He said the two holes at the back were for ventilation and the lamp sits base down in the 763/764 range.
 
Thanks for pursuing the topic, LampyTom. I wonder why no other fixture had to resort to extra holes in the reflector for cooling. Was this the first, or only, ERS from Strand that used a BBD design? With the BBU lamp used in radial units, the heat escapes around the socket, keeping the pinch seal temperature to a reasonable level, but over-heating the socket. Lighting manufacturers didn't yet understand all the rules of convection currents and thermodynamics.

Looking through my notes, I found a post to the Usenet group: rec.arts.theatre.stagecraft, by Martin Moore, buried on my hard drive since 1999. Sadly, it doesn't mention the extra holes. But it does contain great historical information from an inside source. I knew Mr. Moore when he worked for Kliegl Bros. in the 1980s.
for any history buffs out there

T-spot was the marketing take on the internal (derogatory) R&D name --
tin-spot

Originally the design and prototype were in aluminum extrusion. You had buy
a batch to get a couple of samples -- consequently there was a shed, at the
toothpaste factory, full of extrusion for several years. The CCT Sil was
beating the **** out of the 763/4 and marketing wanted an "improved" 763/4
with a zoom option and a plug-in lamp tray etc.

The old Strand Electric's lantern design philosophy was to buy in most of
the housing parts preformed. For example (very innovative at the time) deep
(large) high pressure die castings for the patt. 23 and 123s, heavy
stampings for the patt. 243 and 263/4.

The 263/4 was Strand's response to Century's die cast Leko - the Source Four of
its day (and doesn't history just repeat itself with the SL response!). The
original 263s were first used around the proscenium for **Blitz!** in 62.
They used 120 volt lamps, no 240 volt lamps available till later. 2
lanterns were connected in series - the lamps lasted for ever. This was all
prior to quartz-iodine/tungsten-halogen. Lamps had to burnt cap up, as the
bulb blackened due to deposits of tungsten spattered off the filament. A
long neck and cap up encouraged the blackening to occur on the neck, so not
dimming the lamp output while the filament was still intact. (The TV globes
of the day, had gun shot inside -- when they blackened, you could take the
lamp out of the light, shake it around a bit, and the gun shot took the
blackening off the inside of the bulb)

The 263 designation was without the serrated shutters, the 264 designation
was with. The second set of shutters was something just to be different to
those Yanks. Bi-focal was touted as being able - from box positions, to
give a hard cut off on the pros and a soft cut off on stage - on box sets to
give hard cut off on the ceiling line and soft cut offs within the set.
Most professionals never used the feature.

When the time came to do the tungsten-halogen version of the 263/4 -- towit
the 763/4 -- all that really needed to be done was to turn the existing
263/4s upside down (like the current Selecon *Pacific* range) and put in the
new lamps on a spacer (they didn't darken and so had short necks) - would've
done wonders for pinch seal temperature and consequently lamp life. Lamp
life - always a bugbear of ellipsoidal design.

But somebody in the old Strand Electric had pushed the idea they could avoid
(a) buying in major subassemblies and (b) spending significant sums of money
on their tooling, if they built the housings all in-house. They'd use
smaller stamped parts, made on smaller presses that they could afford to
buy, and by riveting together several smaller parts make a housing.
Around this time Strand sold out to Rank.

But Rank took on the old Strand Electric's (Ken Mould's) grand (and stupid)
plan for all-in-house-under-one-roof manufacturing to be based in
Manchester, and implemented the plan lock-stock-and-barrel in Kirkcaldy,
Fife, Scotland (north over the Firth from Edinburgh, location of the
Scottish play, birthplace of Adam *Wealth of Nations* Smith etc - but not a
theatre in sight).
Previously the Rank Disorganization had made a commitment to government to
use a new (free) factory in Kirkcaldy to provide work for redundant coal
miners in the area. Rank planned on making Aldis equipment there, but
they'd bought Aldis without doing their homework and Kodak Carousel
etc. obsolete Aldis overnight. So the Rank boys desperately needed something
to fill the factory - the spat between John Davis (MD Rank) and Jules Thorn
(MD Thorn) gave them Strand to put there.

So as one result, when the new 763/4s first came out, they clicked up a
storm -- as the various small housing pieces - some nearer and some further
from the lamp - expanding and contracting against each other at the riveted
joints. The 763/4s appeared cheap and nasty as compared to the 263/4s and
the competition (CTT Sils) with integral housings.

The T64/84 carried on the tradition, but only because the Rank powers that
be had implemented the Mould plan. They killed off the A-spot, which
wouldn't have required in-house manufacture of the housings - nothing for
the ex-miners to do.

Arez -Chromatic aberration is a function of the lens(es), not the reflector.

JohnD -You're correct about older,larger incandescent lamps having sand or granules in them so the user could remove the blackening of tungsten deposits. But this only worked with BBD lamps, and as one could imagine, proved a maintenance nightmare. "Whose turn is it to remove and shake the lamps this week?"

Kurt -The document you found appears to me to be a high school or college term paper on the ellipsoidal reflector spotlight. Not exactly an authoritative source, and it doesn't address the multiple hole issue.
.
 
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techieman33

Just a bit of trivia for the younger guys: To follow up on what was left out of the article above, the reason for the non-axial lamp was because the huge incandescent lamps had to be burned as close to base-up as possible. I've heard a few reasons for this, and they're probably all somewhat correct. One being that the filament supports would fail when turned at an extreme angle, and another suggesting that since there was no halogen cycle, the black deposits from the filament could gather near the lamp base rather than on the globe where it would more interfere with the output.

My understanding is that it had to do with how to reduce the heat from the filament on the glass bulb. "In the day" a burn base down lamp was typically a G lamp (Globular). Using this kind of lamp in a Leko would have meant a large hole in the reflector. So they designed it using a T (Tubular) lamp. If you burned the T lamp horizontally the heat from the filament would rise and soften the glass bulb. If you burned it base up, the heat had time to spread out a bit. I have vague memories of sometimes replacing T lamps that the bulb had started to blister on when burned in an improper position.
 
... I have vague memories of sometimes replacing T lamps that the bulb had started to blister on when burned in an improper position.
"Blister" is a bit of an understatement. We called them "pregnant lamps." The bulbous, phallic shapes to which even the 750T12/9 could deform made them downright obscene. When it could no longer fit through the hole in the reflector, the only way to remove the lamp was to open the fixture at the gate. In very rare cases, one had to actually break the envelope in order to remove the lamp.

Kurt -Sure, what the heck; "A" for effort.
.
 
So, about the huge hole to accommodate the lamp...

In the BBU era of ellipsoidals, was it all just a matter of convenience so you were able to re-lamp from the rear of the instrument? From my understanding, the lamp bases (the actual part of the lamp) were never really any larger than a medium prefocus. They wouldn't have been able to counter all of the issues associated with an off-set hole, but it seems as though they would have counteracted some of them by simply designing the fixtures to be re-lamped from the front (many ellipsoidals - like the 360Q - have a hinge at the gate) and having a smaller hole in the reflector since only the base had to fit through and not the entire bulb portion of the lamp.
 
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The hole in the reflector has to be just a little larger than the lamp's envelope. T12 and T14 lamps were common in 6" units; some cannon Lekos could take up to a 3000W T32--huge hole! At the time, no one made "long neck" PS shaped bulbs for stage fixtures. I'm sure there might have been some ERS units that only lamped from the front--the only one I can think of at the moment is the Kliegl Bros. 1357 series which used a double-ended lamp.
 
Just a bit of trivia for the younger guys: To follow up on what was left out of the article above, the reason for the non-axial lamp was because the huge incandescent lamps had to be burned as close to base-up as possible. I've heard a few reasons for this, and they're probably all somewhat correct. One being that the filament supports would fail when turned at an extreme angle, and another suggesting that since there was no halogen cycle, the black deposits from the filament could gather near the lamp base rather than on the globe where it would more interfere with the output.

I found this: http://www.geappliances.com/email/lighting/specifier/2008_07/downloads/HIDBurnOrientation.pdf

The article does some discussion on minor color variance in lamps depending on how they are oriented, as well as how long the lamp has been burned for. Is this possibly another reason for the lamps being burned base up?
 
I found this: http://www.geappliances.com/email/lighting/specifier/2008_07/downloads/HIDBurnOrientation.pdf

The article does some discussion on minor color variance in lamps depending on how they are oriented, as well as how long the lamp has been burned for. Is this possibly another reason for the lamps being burned base up?

That article discusses HID (High Intensity Discharge) lamps which don't play by the same set of rules that quartz-halogen/incandescent lamps do. I'll see if there's any direct correlation when I finish the article, but I'm thinking not.

Update: Yeah, that article is referring to a family of arc lamps (metal halide) which use processes and gasses to create light non-existent in incandescent lighting. Think "gymnasium lighting".

Here's a couple of diagrams showing the differences between each:

Metal Halide:
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Incandescent:
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Though this is just the diagram for a normal household lamp, it isn't terribly different than the incandescent lamps being discussed here (for illustrative purposes, at least).
 
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