Firelight w/o fire
Posted 18 March 2009 - 05:07 PM
in a few months time I'm shooting a fantasy short of a post apocalyptic world. In one of the scenes, people, driven from their homes, have found refuge in an underground hallway of sorts.
Some are gathered around iron vessels they have made a fire in, or at least, that was what we had hoped to do. As it turns out, we can not bring fire into the space we're filming, now at last my question:
are there any tricks or tips to make such a great space look convincingly lit by fire when there's no flame to be seen?
also, how does one best recreate firelight effect if confined to a barrel?
thank you in advance for your time,
Posted 18 March 2009 - 05:26 PM
One thing you might try is to have 4 300w lamps in the bottom of the barrel, facing up, and gelled with either CTS or CTO (I prefer CTS). Have one lamp on constantly, and the others on flicker circuits at varying speeds.
The other thing which helps to sell these gags is if you start your scene with a shot of real flames. As you're not allowed fire in your location, you could do this elsewhere as a close-up. I think that seeing the flames first makes the lighting effect much more plausible, if only by association.
Posted 18 March 2009 - 06:57 PM
I haven't tried it, but for fires burning the distance background you could possibly get away with 'silk fire' - basically pieces of silk attached to a fan, lit up with a gelled spotlight.
Posted 18 March 2009 - 08:41 PM
FAKE FIRE EFFECT
In your case I would recommend small lights with CTO and something to cause a small sourcy smoke. Much of what people perceive as fire is actually back lit smoke. It will really be more effective then the silk fire effect but the silk fire is fun and can be effective if used smartly.
This is actually a very easy and simple effect particularly in HD. It is very helpful to see exactly what you are getting and to shoot with the shutter off to give some motion blur to the flames. In this situation the fire martial would not give us permission to run a flame bar at the location and fire was critical to telling the story of a car crash aftermath. This is an effect I stole from the “Pirates of the Caribbean” ride at Disneyland. I cut several thin long strips of CTO full, ½, and ¼ and the taped them to a fan. Silk would have worked better. I placed them in the foreground of the so they flicked through the frame. I then added a side lit fire effect to the actual scene and back lit smoke behind the car with full and ½ CTO on a flicker effect. I find backlighting smoke is as effective if not more so then actually fire in the shot. I have also started to add CTO back light to my reel fireball explosions. I find that the flash of an explosion is often over to quickly and by back lighting the residue smoke and then dimming it out greatly enhances the effect.
Posted 19 March 2009 - 10:37 AM
But I think Bob's photo demonstrates that you could probably get away with light and smoke - provided of course the location allows smoke.
The other option is to shoot flame elements and then composite them later on in post. Can be tricky and more involved, for example this scene from Knowing has (I think) a few fire elements composited in for safety reasons (also notice that no one told the actor playing the Police Man where the plane was going to actually come from).
But on-set effects are much more satisfying than using VFX.