Jump to content


Photo

Melted gel?


  • Please log in to reply
5 replies to this topic

#1 realfilm

realfilm

    New

  • Basic Members
  • Pip
  • 8 posts
  • Cinematographer

Posted 20 February 2006 - 04:50 PM

Can someone give some advice on the best way to gel, say an Arri 1K, with a 12x12" piece of color gel?

I had used some straw on one that worked ok by placing it on the barn doors with the usual clothes hangers. This kept it away from the lens a few inches at least, depending on the door position. I placed a 3/4 CTB in the same way and it started melting/warping within 30 sec. These are Lee gels made for lights.

What's the best way to do this? Do I need a heat sheild (clear gel placed behind the color)? Or am I using the wrong type of gel or what?
  • 0

#2 Matt Sandstrom

Matt Sandstrom
  • Basic Members
  • PipPipPipPip
  • 464 posts
  • Director
  • Stockholm, Sweden

Posted 20 February 2006 - 05:07 PM

let it warp and buckle as much as it wants. it won't melt. if it still does then yes, you're using the wrong gel.

/matt
  • 0

#3 Dan Salzmann

Dan Salzmann
  • Basic Members
  • PipPipPipPip
  • 1143 posts
  • Cinematographer
  • Paris, France

Posted 20 February 2006 - 07:24 PM

Darker colored gels absorb heat more than lighter colored gels.
  • 0

#4 timHealy

timHealy
  • Basic Members
  • PipPipPipPip
  • 1252 posts
  • Other
  • New York

Posted 20 February 2006 - 08:48 PM

Lee or Rosco gel can be used inside the doors (close to the lens) or on the outside of the doors with no problem with 1k fresnels. What kind of gel are you using? What kind of 1k are you using?

Generally speaking one can use Rosco or Lee inside the doors from 5k down on down. But with 5k's and 2k's you want to let it billow out so some ventilation gets in there. Outside the doors is no problem with these lights too but I prefer to go inside the doors when I can. You wind up using less gel and there is less chance of white light spill.

On 10k's and up, most large HMI's, gel on a frame works better than on the doors. On open face lights like one and 2k blondes and redheads, on the outside of the doors or a frame. On pars of all sizes keeping the gel on a frame as far away from the light the better it will last. Heat shield will also help but don't let layers of gel touch. Separately they will last for quite some time, but if they touch under use they will melt each other. Rosco sells a super heat shield that comes in sheets but the right side of the material must face the light source. You can tell the right side by using a continuity meter.

Best

Tim
  • 0

#5 Mike Hall

Mike Hall
  • Basic Members
  • PipPip
  • 37 posts
  • Gaffer

Posted 20 February 2006 - 09:43 PM

The farther from the element, the better. Most gels are formulated to take the heat of a fresnel.

That said, an open faced light generates five times the heat (at the hot spots) of a fresnel, and you will have burn-thru. There are no gels that can surpass the heat of a bare tungsten bulb, so the rule of thumb is: the farther from the source (bulb) the better. If you must use a color very close to an open bulb, it is best to use a glass filter. Otherwise, back it off at least until it fills the barn doors.
  • 0

#6 bolshevik

bolshevik
  • Basic Members
  • PipPip
  • 16 posts
  • Student

Posted 06 March 2006 - 04:46 PM

use rosco gels. theyre more expensive but can take more heat than lee.
  • 0


Rig Wheels Passport

Tai Audio

Paralinx LLC

FJS International, LLC

Willys Widgets

Gamma Ray Digital Inc

Metropolis Post

Visual Products

Abel Cine

Ritter Battery

CineLab

Glidecam

CineTape

The Slider

Technodolly

Wooden Camera

Opal

rebotnix Technologies

Media Blackout - Custom Cables and AKS

Broadcast Solutions Inc

Aerial Filmworks

Aerial Filmworks

Visual Products

Abel Cine

Ritter Battery

Metropolis Post

The Slider

Willys Widgets

Gamma Ray Digital Inc

Rig Wheels Passport

Technodolly

Tai Audio

Broadcast Solutions Inc

Media Blackout - Custom Cables and AKS

FJS International, LLC

CineTape

rebotnix Technologies

Glidecam

CineLab

Paralinx LLC

Opal

Wooden Camera