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Author Topic: Cross Polarizing A Hot Light  (Read 810 times)

JoeKitchen

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Cross Polarizing A Hot Light
« on: April 28, 2017, 12:03:18 PM »

I am thinking about producing a couple of beverage product videos soon and will need to cross polarize a 200w or 420w tungsten fresnel.  I have a spare 4 inch Lee glass polarizer for the Lee filter system that I am not using. 

Would I be safe using this in a hot light?  Do you think the heat would ruin it or crack it? 

Thanks. 
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Joe Kitchen
www.josephmkitchen.com

"Photography is one percent inspiration and ninety-nine percent moving furniture."  Arnold Newman
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Stephen Ray

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Re: Cross Polarizing A Hot Light
« Reply #1 on: April 29, 2017, 02:03:12 AM »

A common method for hot lights is to use a heat-absorbing glass (which can be almost any glass) between the lamp and polarizing film. Your fresnel is already acting as a heat buffer but I would still be cautious with the Lee filter.

I would clip a piece of polarizing film (approx 12 x12 inches) at the end of the barn doors. If there is still too much heat, I would get a piece of 1/4 inch glass (water-clear if available) the size of the barn door scrim holder and have that cut in half. Example would be 8x8 inch scrim slot now would hold two pieces of 4x8 inch heat-absorbing glass. This is fairly standard in the Hollywood area and it works for open-face hot lamps as well.

I hope this helps. 

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BobDavid

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Re: Cross Polarizing A Hot Light
« Reply #2 on: May 07, 2017, 03:24:17 PM »

Rosco has a thin cellophane-like material that works as a heat shield. it is easier to work with than glass.
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ynp

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Re: Cross Polarizing A Hot Light
« Reply #3 on: May 12, 2017, 06:00:59 PM »

Rosco has a thin cellophane-like material that works as a heat shield. it is easier to work with than glass.
Concur with this.

I use those Rosco heat diffusers with the Rosco CineGel film polarizers on smaller Chimera hot proof softboxes.
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