# How much glove would 6x9 burn if a 6x9 could burn glove?

#### Charc

##### Well-Known Member
A 6x9 would burn all the glove a 6x9 could burn, if a 6x9 could burn glove.

(I hope we all got that joke. Yes? Moving on.)

$%!& those things get hot! I remember reading that the 6x9 was notorious for burning out gel, as the focal point is just about at the end of the barrel. I'd like to confirm that. However, the instrument didn't have any gel in it... Let's start by an introduction to my gloves: Ironclad Heatworx 450 Gloves In a few seconds the 6x9 (at full) made my gloves (capable of withstanding intermittent heat up to 450º F) start to smoke. In fact I think some of that heat made its way into my hand, as it feels a little sore. Luckily, the glove took the brunt of it. Funny as &^#$ though. I look down to see smoke rising from my hand.

I'm sure all of you are scratching your heads now, wondering how on earth I managed that. You're probably wondering if you read that right, did I actually stick my hand in front of the light and leave it for a period of time?

Yep.

I had to focus the instrument, and due to certain "rigging" (that we won't get in to) I had limited access to the instrument, and found my self in a position where I had to run the barrel in by pushing on it from underneath.

That didn't last long.

So, remember:
"Hand before light, it's alright. Light before hand, leaves a new brand."

That was my take on the age old saying: "Liquor before beer, you're in the clear. Beer before liquor, makes you sicker." Or wait... do I have that backwards?

#### icewolf08

##### CBMod
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Now you know how the ants under your magnifying glass feel!

#### propmonkey

##### Well-Known Member
ive done that with my heavy utility ironcalde just to see how hot it is and with in 2 seconds i got smoke. ive also managed to melt one of the rubber thumb pads on my old gloves. im just glade it was \$20 gloves and not my skin.

#### BillESC

##### Well-Known Member
Haven't you ever cooked a hamburger or hot dogs on a leko? Used to do it in the poor summer theatre days.

#### stantonsound

##### Active Member
I was forced to buy a pair of overpriced SetWare Hot Hands gloves......long story but someone stole my gloves and I had to do a focus in a theatre that only used the old Altman 6x whatever's and Strand fixtures. These gloves are GREAT..... almost worth the ridiculous price that I paid for them.

Anyway, I believe that the 36degree lenses are the worst on gels. From experience, the 36's always go first.

#### gafftaper

##### Senior Team
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Someone please correct me if I'm wrong here, but the focal length on the 6x9 isn't what makes them so hot... although anything placed at the focal point 9 inches out is going to burn!

Didn't the old instruments produce more heat in the light path due to the fact that they have a metal reflector. Meaning they reflect all the Infrared forward into the gate. The newer instruments have dichroic glass reflectors which pass a large percentage of the I.R. into the body of the instrument, reflecting mostly just the visible light forward into the gate. Thus they are cooler out front.

#### propmonkey

##### Well-Known Member
Haven't you ever cooked a hamburger or hot dogs on a leko? Used to do it in the poor summer theatre days.

ha. i saw on roadie.net some guys cooking food on a par64.

ive warmed up a slice of pizza once by lowering an electric and pointing it at my pizza for a few minutes. worked pretty well

#### avkid

##### Not a New User
Fight Leukemia
"Liquor before beer, you're in the clear. Beer before liquor, makes you sicker." Or wait... do I have that backwards?
Right result, wrong order.
"Beer then liquor, you've never been sicker. Liquor then beer, you're in the clear,"

#### propmonkey

##### Well-Known Member
Right result, wrong order.
"Beer then liquor, you've never been sicker. Liquor then beer, you're in the clear,"

i was told never to mix the two anyways...

#### avkid

##### Not a New User
Fight Leukemia
i was told never to mix the two anyways...
Ross, shhhh...

They need to learn their own life lessons.

#### derekleffew

##### Resident Curmudgeon
Senior Team
Someone please correct me if I'm wrong here, but the focal length on the 6x9 isn't what makes them so hot... although anything placed at the focal point 9 inches out is going to burn!

Didn't the old instruments produce more heat in the light path due to the fact that they have a metal reflector. Meaning they reflect all the Infrared forward into the gate. The newer instruments have dichroic glass reflectors which pass a large percentage of the I.R. into the body of the instrument, reflecting mostly just the visible light forward into the gate. Thus they are cooler out front.
Absolutely correct.

Ironic that when the SourceFour™ was introduced in 1992, many electricians were worried that the glass reflector was too delicate and could never hold up, and now most won't use anything else, given the choice.

#### gafftaper

##### Senior Team
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Well as long as we are on the topic (sort of)...

Question One...
We all have read the brochure... the Source Four is more efficient than an old ERS, producing the same amount of light as a 1000 watt instrument with a 575 watt lamp... or something like that. But where does the increase in efficiency come from? Is it in the change to the glass dichroic reflector? superior glass in the lenses? more efficient lamps? A combination?

Question Two....
As has already been discussed, the dichroic glass reflector helps reduce heat in the light put out the front of an ERS. Was there also some decrease in heat by switching to the newer lamp styles? To be specific, does an HPL produce more visible light and less I.R. than older lamps creating a "cooler beam"?

#### JD

##### Well-Known Member
Glass is a funny thing. With lenses, the angle at which light hits it changes the ratio of what is passed as compared to what is reflected. I think when they designed the Source 4, they spent some time working that out and that the added efficiency is gained by less light being reflected back and wasted. The reflector is also key. Even though they all look very shiny, some light does get absorbed. After all, if an aluminum reflector truly reflected 100%, it wouldn't get hot!

#### JD

##### Well-Known Member
Question Two....
As has already been discussed, the dichroic glass reflector helps reduce heat in the light put out the front of an ERS. Was there also some decrease in heat by switching to the newer lamp styles? To be specific, does an HPL produce more visible light and less I.R. than older lamps creating a "cooler beam"?

Sorry, I missed the second question!

It is hard to change the ratio of visible/IR light without changing the color temperature. Tungsten, when heated to a certain temperature, will put out a specific spectrum of light containing the same proportions of IR and UV. So, I don't think that is the advantage of the newer lamps. Watts are watts, and any given wattage of a tungsten lamp at a certain color temperature will throw the same amount of heat.

What can be changed is the configuration of the filament. Lets face it, we are trying to make something that looks like a glowing spring produce an even field of light! Ship could probably fill in a lot more, but basically there are compromises being made. The tighter and closer the filament segments, LCL, and general area are, the better the lamp is optically. However, these same things make the lamp fragile and shorten its life! Filaments sag and when sections touch, bang, that's the end. So, it is a compromise, but basically, newer lamps are designed from the lessons learned so newer styles tend to be better. Cooler, no, but better.

EDIT:
LCL (light center length) is not the factor, but the overall length of the filament structure is.

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#### icewolf08

##### CBMod
CB Mods
Well as long as we are on the topic (sort of)...
Question One...
We all have read the brochure... the Source Four is more efficient than an old ERS, producing the same amount of light as a 1000 watt instrument with a 575 watt lamp... or something like that. But where does the increase in efficiency come from? Is it in the change to the glass dichroic reflector? superior glass in the lenses? more efficient lamps? A combination?
The efficiency comes from a combination of the lamp, reflector and lenses. As we know, the physics of light says that the most efficient source for for an ERS fixture is a point source. Infinitely small and outputting lots of light (the first person to invent the "anti-singularity" could make one heck of a lamp). Take a look at the standard 1kW lamp that we have all started to hate, but used to use all the time, the FEL. It has a very long filament with wide coils compared to newer lamps, making it not a great point source. The HPL has four (hence the name Source Four) filaments that are much tighter coils and create a tighter point source.

Now, couple the new lamps with the new reflector. The reflector was deigned around the lamp. Since we know that the lamp is not a true point source, the designers calculate the optimum placement of the facets on the reflector to catch and focus as much of the light as possible back to the second foci. I am not sure about the optical properties compared to the old metal reflectors, but when you consider that all precision optical mirrors are made of glass, there is probably a n optical reasoning for that.

Then we get to lenses. Look at your 360Q or Strand Lekolight. Take out the lens tube and look at it. That is one big honking pice of glass. Many of the old lenses were not manufactured out of very high quality glass, and if you look at them you can often see imperfections. Couple that with the amount of glass that the light has to pass through, and it really is no wonder there is significant output drop. The source four's new lens design makes a huge difference. Now, in the most common lenses only one (the 36˚) has two lenses, and the total amount of glass is much less than even one lens from a 6x unit. The Source four lenses are made from a much higher quality glass, and are precision ground. We are not talking photographic quality, but the same aspheric idea, which keeps the amount of glass used, down.

So it really is a combination of all these factors that make todays modern instruments more efficient than older fixtures.

#### gafftaper

##### Senior Team
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Thanks guys, that's interesting I know all those things just never put them together in that order. For example I had always thought that the multiple facets to the mirror were just to aim the light the best way possible out the gate... which is sort of true but the real reason is correcting for the lack of a point source. Makes a lot of sense. If only I would have figured that out in about 1985...

#### derekleffew

##### Resident Curmudgeon
Senior Team
Aha! You've discovered the dark, dirty, secret: Ellipsoidal Reflector Spotlights DON'T actually have ellipsoidal-shaped reflectors, and haven't since the 1970s. Rather, the reflector is made of a series of planar (flat) rectangles, arranged in the shape of an ellipsoid, specifically to compensate for the fact that an incandescent filament is NOT a point source. [Good call on the 4-Source HPL lamp of the SourceFour™, Icewolf08--it's amazing how many people don't know why they're called "Source Fours."] In the '60s/'70s, the first improvement was the "flatted" reflector design--a series of rings around the reflector; then "double-flatted," with lines going parallel and perpendicular to the short axis of the ellipsoid. Strand-Century's spec sheets of the '70s boasted a "double-flatted Alzakreflector" (Alzak™ is a patented process to polish aluminum). Berkey-Colortran's big selling point was the use of "low-expansion borosilicate glass" in their lenses; later came "anti-reflective coating." Carbon-arc sources and arc lamps approach a point source, and therefore you won't see a "flatted" reflector in a Super Trouper or moving light.

Calling them a "double-flatted approximately ellipsoidal-shaped reflector spotlight" or DFAESRS, is just too much of a mouthful, hence the popularity of the term "Leko." Most people I know call a SourceFour™ a Leko, to differentiate it from a SourceFour PAR, which isn't even a PAR at all if it's an "MCM," but only if it's an "EA," but that's a discussion for a different thread altogether! And don't get me started on the PARnel™!

This is the sort of stuff our colleges should be teaching, but I bet they're not, and it's a rare text that goes into such in-depth explanation of the ERS.

#### gafftapegreenia

##### CBMod
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As I've said before, for me:

A "Leko" is any ERS pre-Source 4

A "Source 4" is a Source 4 ERS

A "PAR" is a regular par can.

A "Source 4 PAR" is just that.

A PARnel is its own animal, and one that TOO MANY people get confused with the Source 4 PAR.

Good thread. Reminds me of the one highschool I was in where the old Kliegl 6x9's (?) with tungsten-halogen retrofits were outperforming the 360Q's. I think that must have something to do with the actual size of the reflector that was designed for the incandescent, non-halogen lamps. Your thoughts?

#### derekleffew

##### Resident Curmudgeon
Senior Team
As I've said before, for me:

A "Leko" is any ERS pre-Source 4

A "Source 4" is a Source 4 ERS

A "PAR" is a regular par can.

A "Source 4 PAR" is just that.

A PARnel is its own animal, and one that TOO MANY people get confused with the Source 4 PAR.
Good rules to live by, but I'm just saying that's not the way it's done in MY world (which Van keeps saying is not the real world). And I would have to argue about "Leko being any ERS pre-S4." We all know "Leko" is a registered trademark of what used to be Century Lighting. Strand Lighting seems to have dropped the name, so maybe it can now be used for ANY ERS. Since today I don't EVER use any ERSs except S4s, (even Selecon Pacifics are rare in Las Vegas); thus it's "Source4 PARs" and "Source4 Lekos."

Good thread. Reminds me of the one highschool I was in where the old Kliegl 6x9's (?) with tungsten-halogen retrofits were outperforming the 360Q's. I think that must have something to do with the actual size of the reflector that was designed for the incandescent, non-halogen lamps. Your thoughts?

I'm guessing the Altman 360Qs were using the 750W EHG lamp, and the Kliegl fixtures had the 750W EGG, correct? The Kliegls were most likely either 6x8 sgl-step lens, or 6x3 3/4 sgl-step lens, so a savings right there of a single thin lens, rather than two thick PC lenses.

Both lamps above have a lumen output of 15,000, so identical in that regard. Also the same color temperature of 3000K.

A Kliegl 6x8 actually compares to a 360Q-6x16. A Kliegl 6x3 3/4 is wider than a 6x9 (EFL=4.5") but slightly narrower than a 4 1/2 x 6 1/2, (EFL=3.25") so it's hard to make a direct comparison.

The Kliegl had an exactly ellipsoidal-shaped reflector, while the Altman was double-flatted. The size of the reflector is not really an issue, but the size and location of the hole for the lamp to penetrate definitely affects the quality of the beam, as well as the black-painted risers on the stepped lenses Kliegl used. I'm not surprised that the Kliegls were brighter, but obviously the 360Qs had a much better field. The Altman may have had "green" lenses also, thereby lessening even more light output.

SteveB and STEVETERRY, please don't jump in here with "why are we spending time discussing archaic technology, when we could be buying shiny, new, SOTA SourceFours™? Gafftapegreenia asked the question, I merely answered it.

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#### gafftapegreenia

##### CBMod
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Thanks Derek.

Don't get me wrong, love the Source 4, but it makes one appreciate them more when you know why they are so great.