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Dichroic Filters

Published : 25th July 2004

>......there were some Kool Light fixtures out there that emulated FAY lights but used DYX globes with dichroic reflectors and lenses...Does anyone else remember their existence?.....<

Yes I remember them but never used them. I also recall the square glass dichroic filters that were around for Lowell lights in the 600-1K range. Haven't seen them much lately.

Dichroics were a choice for color correction before the advent of the HMI's. They were quiet in the wind, being glass, and usually were made for specific location fixtures. There were no clothespins needed, like gels, and they were usually designed into the barndoor structure of the fixture. They were fragile being glass. I do recall the color temp being rather questionable but some people swore by them.

Anyone still use them these days?

Jim Sofranko (permanently lagged)
NY/DP



>there were some Kool Light fixtures out there that emulated FAY lights >but used DYX globes with dichroic reflectors and lenses...Does anyone >else remember their existence?

Cool lights were first used on the TV series "The Rockford Files". Legend has it that Jim Garner hated the heat put out by the lighting techniques at the time. Slow film stock, and Brutes and 9 and 12 lights the norm. I believe Garner helped fund their development. A short time later, they were available in the rental market, but fell victim to the HMI ground swell.

Dichroic lenses were available for open face instruments such as Mighty and Mickey Moles. rendering a 2k a 1k (at best!), they fit into the barn door ears of the before mentioned lights. They can also be found in the same pile with the cool lights at the back of most older established lighting rental facilities.

Paul Varrieur S.O.C.
Atlanta, Ga.



>Kool Light fixtures out there that emulated FAY lights but used DYX >globes with dichroic reflectors and lenses...the whole idea was to >minimize the infrared to keep the heat away from the subject.

Used them as alternative to HMI's in reducing heat, I remember they used 3400K lamps and so had a shortish life, but the thing worked well.

I can't confirm DYX are 3400, not home & don't have my catalogues. They (it was Cool-Lite, no ?) said the 3400K lamps radiated less UV.

Now they sell Cool-Lux, you know those obies for video cameras. I think it's the same folks.

Sam Wells



I remember these from the Mole Richardson catalogue - they took DYS globes, the same globe that Tweenies used to take. The CoolLite used dichroic over each lamp. The DYS is 3200 Kelvin or so. I think that the short life was due to the design of the globe and its particularly weak filament.

Ted Hayash
CLT
Los Angeles, CA



>Kool Lights", anyone remember their existence?

I believe Kool Lights were first used on the set of "Rockford Files" in the seventies. Legend has it that they were invented because Jim Garner hated the intense heat that was present on the set. Blame 5254 and the Brute arcs, 9,12 lights, the usual television lighting of the period. It is also believed that Garner had money invested in these instruments.

They showed up as rental items soon after that, but were rendered obsolete when HMI's became vogue. As far as Dichroic lenses are concerned, I remember the glass ones that were made to fit over open face Mighty and Mickey Mole Richardson’s. They would turn a 2k into a daylight balanced 1k (at best). You can find them heaped next to cool lights in the back of older Lighting Equipment Rental houses.

Paul Varrieur S.O.C.



>The CoolLite used dichroic over each lamp. The DYS is 3200 Kelvin or >so. I think that the short life was due to the design of the globe and its >particularly weak filament

I distinctly remember 3400K lamps the first time we used it & being surprised at this. I guess they weren't DYS, then.

Sam Wells



Sam Wells writes :

>Now they sell Cool-Lux, you know those obies for video cameras. I think >it's the same folks.

Ah, yes. You can get two-pin 150W dichroic-reflector bulbs for the Cool-Luxes. Anyone know whether those are available in Edison screw-base configuration for use in Lowell L-lights?

Dan Drasin
Producer/DP
Marin County, CA



Jim Sofranko wrote:

>Dichroics were a choice for color correction before the advent of the >HMI's. ... I do recall the color temp being rather questionable but some >people swore by them....

I used them on a short film a couple of years ago because we didn't have the budget for big HMI's so I ordered 2 of the 9-light Maxi-Brutes and a bunch of individual Mole-Pars and had them all stocked with dichroic PAR64 globes. It was a night exterior and I mounted the Maxis and the Pars on a condor and used them to light up the location which was an exterior of a house at the edge of the woods.

I think I color temped them out at about 4600K, which is plenty blue for my taste- about like putting quarter CTO on an HMI. They worked pretty well as far as the amount of light they put out. But one thing to watch out for is "fringing" of colors- If you are seeing the ground and shadows, you will not get a single sharp shadow like you would from a single source such as an 18K. In fact you will get a sort-of multiple shadow effect from the multiple sources with different colors halating (is that a word?) ever so slightly. I think that we may have put some slight diffusion to help with this problem, but even looking at the pine trees being backlit I could see different colors being split apart like a prism (hope that makes sense!)

But over all a pretty good solution when budget is a big concern.

Toby Birney
L.A., CA and Vilnius, Lithuania



>There is always FAY lamps, 650 watts and from Mole configurations >from 1lamp to 12 in one fixture

I don't think they make FAY’s any more...though I think I still have a case of minimal hour globes back in NY somewhere...FAY’s have dichroic filters on the front of them, but they do not have dichroic reflectors - they are regular PAR (Polished aluminised reflectors) which are metal coating on the inside of the glass ...reflecting a lot of the IR back out the front of the fixture, as anyone who has warmed pizza on a mini-brute can attest. Having missed the beginning of this thread, I gather the issue at hand is heat getting on the subject, but I don't know whether the specific interest is in daylight balance or tungsten balance.

This past summer I attended a demo of a fresnel using the new calcium discharge globes that are reputedly tungsten balanced but with much more light per watt (and therefore less heat per lumen as it were.)

Has anyone actually used these on a shoot yet?

Mark Weingartner
LA based but off base right now.



I remember doing table-tops years ago with an LTM fibre-optic unit.

It was composed of a main box with an HMI fixture [of some sort] with several ports...you could plug in a think bundle which then allowed you to plug in a 'split' bundle, and so on until you had fibre-optics down to 1/8" think...or up to 1" think. I believe the medium sized tubes [1/2"?] had a cool arrangement that allowed you to snap on tiny little fresnel lenses!

We could drill holes through sweep tables to aim the fibre-optics where we needed them. We used these on NiQuil spots where we were back lighting the tiny gel-capsules.

Of course, the director wanted another shot where the actor picked up the box...and wanted the capsules to remain backlit...so I hand them rig up tiny doll-house fluorescent tubes [about 1 1/4" long] inside the box...run off a garage door control battery [we needed like 18vDC for it to work]..had a tiny on/off switch which the actor could control to save battery life between takes...worked pretty well!

Anyone know if these LTM units are still around?

Cheers,
Jeff Barklage, s.o.c.
US based DP
www.barklage.com



Mark Weingartner wrote:

>I don't think they make FAY's any more...though I think I still have a >case of minimal hour globes back in NY somewhere

We bought a bunch of Fays last summer for our twelve and nine lights. The difficult to find items are FBEs, which are the same thing but with screw terminals, rather than ferules. Finally found some at Barbizon in Denver.

(We use these in some really handy little lightweight aluminium 5 lights that were custom made by MGM who knows how long ago.)

Wade K. Ramsey, DP
Dept. of Cinema & Video Production
Bob Jones University
Greenville, SC 29614



Wade Ramset writes :

>We bought a bunch of Fays last summer for our twelve and nine lights. >The difficult to find items are FBEs, which are the same thing but with >screw terminals, rather than ferules.

If they were orange, they were made about 1976.

In pinch, FBE's can be used in Molefays, and screw terminals from burned out FBE's can be silver soldered onto FAY's. Found out the hard way, when we lost a neutral.

Brian Heller
IA 600 DP


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