R90 Gels burning instantly!

[Galen]

While trying to get color in my source4s the other day, I noticed that our cuts of Rosco 90 (Dark Yellow Green) were burning through faster than I could focus them! I moved the frames as far away from the lamp as possible, but that still only leaves them good for one show at the longest. Pretty sure the lamps are 575s although I'm not in the theatre right now. Any suggestions?

 

[Galen]

I forgot the number one forum rule: Search First. I just found a good thread on it here. Might as well lock this thread up :/ Sorry guys.

 

[Les]

No worries! Unlike many forums, we do not look down on reviving old topics so if you feel like contributing, feel free to post your findings.

 

[hobbsies]

I was having an issue with an L201 burning instantly in a 26* fixture. I tried to adjust the bench, but the unit was pretty poorly maintained, which made it impossible to turn the bench knob. I ran the barrel out a bit which seemed to help. I think it's an issue of a slightly mis-aligned lamp in the reflector in combination with a dirty lens muddling the focal point for the beam.

 

[Floobydust]

Consider replacing them with dichroic glass gels.

 

[gafftapegreenia]

Hey, Galen, which degree S4 are you using the R90 in?

 

[Galen]

Hey, Galen, which degree S4 are you using the R90 in?

Pretty sure it was a 35 but we've already switched up our hang for another show (20 touring shows this season, not to mention local acts and chamber music spotlights) As it stands the technical director is going to buy me some Rosco Super Heat Shield next time we call in for gels

 

[gafftapegreenia]

Pretty sure it was a 35 but we've already switched up our hang for another show (20 touring shows this season, not to mention local acts and chamber music spotlights) As it stands the technical director is going to buy me some Rosco Super Heat Shield next time we call in for gels

Ah, I was going to say that depending on the beam spread a color extender might be your best friend.

 

[2mojo2]

Yes.
Not just heat shield but extenders.
We had a very similar problem with some relatively low-transmission gels.

 

[schwei22]

It may also be that you are using 750watt lamps instead of 575. 750's will burn through saturation very quickly.

 

[Kelite]

While traditional 'heat shield' provides a thin barrier of clear plastic between the lens and the gel, Apollo Gel Shield offers UV and IR protection. Apollo Gel Shield is a dichroic coated, 7 mil optically clear barrier.

http://www.apollodesign.net/Products/View/1796.aspx

http://downloads.goapollo.com/Gel Shield1008.pdf

 

[hobbsies]

Keith, do you think that heat shield should be separate from the gel, or can it be in the same frame as the gel, similar to frost? I was under the impression that heat shield needed to be separate from the gel, either using a barn door or color extender.

 

[Kelite]

Great question,
As a rule, whenever an air space provides the buffer between the shield and the color, the color benefits from longer life. Installation in the same frame is good- separate frames with air space between is better.

 

[hobbsies]

Ah, 2 different frames, good idea when there's no color extender/barn door!