70 Degree Source Four

[ScaredOfHeightsLD]

Hello everyone,
I just got back from my hang this morning and we are trying out the S4 70 degree barrels, which on the whole I am very impressed with. However one fixture seems to be continually burning through the gel within seconds of turning the fixture on.
A little background: The fixture is a 70 degree S4 lamped at 750w with a Rosco 74 Gel in it (4% Transmission). We have an identical fixture with the same gel in it (it has been perforated) which has not been burning.
What we have tried: Lamping it down to 575w, perfing the gel, running the barrel in and out.
Has anyone else ran into this problem or have any recommendations. I do have a light in the rig with a R32 gel that could be swapped if you think it is the lens tube. We also have two weeks to opening so I could pick up another one from the rental shop.
Thanks in advance for you help. Hope all is well
-Mike Berger

[SerraAva]

The 90 degree and 70 degree lenses both cook gel very fast. You can't also us a gel extender with them, since the beam comes out at a very wide angle. Great lenses for short shots, but with gobos they can be tricky because they are so big that even going straight on can throw the edges or the center of the gobo out of focus. Have a few in stock and love the things.

[Sean]

Originally Posted by ScaredOfHeightsLD

Hello everyone,
I just got back from my hang this morning and we are trying out the S4 70 degree barrels, which on the whole I am very impressed with. However one fixture seems to be continually burning through the gel within seconds of turning the fixture on.
A little background: The fixture is a 70 degree S4 lamped at 750w with a Rosco 74 Gel in it (4% Transmission). We have an identical fixture with the same gel in it (it has been perforated) which has not been burning.
What we have tried: Lamping it down to 575w, perfing the gel, running the barrel in and out.
Has anyone else ran into this problem or have any recommendations. I do have a light in the rig with a R32 gel that could be swapped if you think it is the lens tube. We also have two weeks to opening so I could pick up another one from the rental shop.
Thanks in advance for you help. Hope all is well
-Mike Berger

You probably need to bench the unit. A very flat field will help a bit.

It's also been my experience with 70° and 90° fixtures that very minor changes in the field can have a huge impact on gel life.

You'll probably want to try making a "tent" out of the gel and blacktak-ing to the front of the light. Even then you'll probably have to change it often.

Good luck.

--Sean

[gafftaper]

Originally Posted by Sean

You probably need to bench the unit. A very flat field will help a bit.
It's also been my experience with 70° and 90° fixtures that very minor changes in the field can have a huge impact on gel life.
You'll probably want to try making a "tent" out of the gel and blacktak-ing to the front of the light. Even then you'll probably have to change it often.
Good luck.
--Sean

Sean's nailed it, you didn't mention focusing the lamp itself. If one is burning gel immediately and the one next to it isn't, the problem is most likely the position of the lamp location in the reflector. Bench it and see how it works.

[derekleffew]

Originally Posted by Sean

...You'll probably want to try making a "tent" out of the gel and blacktak-ing to the front of the light. Even then you'll probably have to change it often...

I've always called that "diapering" the light, but I like the term "tenting" much better. If it's only one unit that's causing grief, I say yes, swap barrels and try a bench focus and different edge. Otherwise, I would suggest this:

[gafftaper]

Originally Posted by derekleffew

I've always called that "diapering" the light, but I like the term "tenting" much better. If it's only one unit that's causing grief, I say yes, swap barrels and try a bench focus and different edge. Otherwise, I would suggest this:

Of course they aren't for sale yet... Plus we've kept Keith so busy stuffing boxes with free gel books and gum that it may be a while until he gets around to putting them together.

[ScaredOfHeightsLD]

Thanks guys, I'll take a look at it tomorrow during rehearsal. I'll let you know what works.
-Mike

[ScaredOfHeightsLD]

UPDATE: We've tried numerous things from swapping fixtures to droping to a 575w lamp, perfing, and its still burning through on that one fixture. We wound up dropping down to a R68 from an R74. I'm not thrilled with the solution but we still have a week till opening if anyone has any suggestions. I was thinking of gel extenders? is it worth the trip to the rental shop?
Thanks
-Mike

[derekleffew]

Originally Posted by ScaredOfHeightsLD

...I was thinking of gel extenders? is it worth the trip to the rental shop?...

Sadly no. Even the 3" (deep) color extender from City Theatrical is too long and will impact the wide beam of a 70° beam. The best advice I've seen would be to "tent" the color onto the fixture, using BlackTak™, and with Apollo Gel Shield in the colorframe. FWIW, I like R68 better than R74 for the exact reason of transmission. Perhaps also try Lee Filters HT074.

[cutlunch]

Have you reset the lamp in it's base as per the instructions in the Source 4 manual?
Also did you read this document "Source Four 14, 70, 90 Degree Lens Tube User Manual Supplement" ?
It shows they way the Source 4 needs to be focused for the best Gel life.

You can find it on the Source 4 support page found here:
http://www.etcconnect.com/product.do....aspx?ID=20080

If only 1 Source 4 with the same Gel is burning then I would say it has to be how the lamp base is positioned.