Jump to content




Photo

Effects of Haze (not fog) on front projection VFX

front projection VFX Haze

  • Please log in to reply
6 replies to this topic

#1 Daniel Reed

Daniel Reed
  • Basic Members
  • PipPip
  • 28 posts
  • Other
  • San Francisco

Posted 16 June 2016 - 07:25 PM

Greetings again,

 

What are the effects of a haze filled set on front projection VFX techniques?

Before I test myself, I'm reaching out instead of re-inventing a mistake  :lol:

 

The haze is meant for adding depth and the illusion of indoor smoke.

This is for a static/locked shot meant to create the illusion of a living room on fire,

with talent on a couch (think Syndoche NY, Barton Fink).

 

My thought is:

Since the projected light is in parallel to the recorded light,

the evenly dense haze will appear brighter/more dense by reflecting light,

will not create the appearance of light pillars,

but will reduce the power and effectiveness of the Scrotchlite screen.

 

My expanded question comes down to:

Will haze defeat too much light, block the subject, and make the screen unusable?

Perhaps a balance can me made employing minor amounts of haze. 

 

My recent post regarding filming the illusion of fire,

got me thinking about front projection as one of several "tricks" to use at once:
http://www.cinematog...showtopic=71850

 

FPT.png?raw=1

 

Thanks for all advise and feedback!

 

 

Recommendations on a "good-enough-and-under-a-grand" digital projector are welcomed.

 

Or any recommendations on where to rent a better-more-pro projector in the SF Bay area.


Edited by Daniel Reed, 16 June 2016 - 07:35 PM.

  • 0




#2 Stuart Brereton

Stuart Brereton
  • Basic Members
  • PipPipPipPip
  • 2576 posts
  • Cinematographer
  • Los Angeles

Posted 16 June 2016 - 08:57 PM

Haze is more visible when back lit, rather than front lit, but the presence of haze in the path of the projector will reduce the intensity of the projection, and the scattering effect of the atomized fluid will likely reduce the contrast of the screen.

 

Another thought is that the haze will give visible depth to the space, and therefore might defeat the illusion that the projection is trying to achieve.


  • 0

#3 Shawn Sagady

Shawn Sagady
  • Basic Members
  • PipPipPip
  • 162 posts
  • Cinematographer
  • Maryland

Posted 17 June 2016 - 02:41 AM

Well there are some errors in your illustration as light does not bounce directly back like that.  You will see a density of the haze in front of the subject no matter how you do it.  I can tell you looking down the beam of a light through haze makes a bright circle of sorts, so I don't know that the illusion you are looking for will work.  What exactly is the end goal here? What are you trying to achieve? 


  • 0

#4 Daniel Reed

Daniel Reed
  • Basic Members
  • PipPip
  • 28 posts
  • Other
  • San Francisco

Posted 17 June 2016 - 07:25 PM

Hi Shawn, thanks for the note on circles.

 

Maybe I can phrase my question better.

 

Can haze be used when doing front projection VFX shots?

 

ie

Will front projection create a usable image on a background screen in a haze filled room? 

 

 

Image talent sitting on a couch while parts of a room are on fire:

 

The haze is meant for adding depth and the illusion of indoor smoke.

This is for a static/locked shot meant to create the illusion of a living room on fire,

with talent on a couch (think Syndoche NY, Barton Fink).

 


Edited by Daniel Reed, 17 June 2016 - 07:31 PM.

  • 0

#5 Shawn Sagady

Shawn Sagady
  • Basic Members
  • PipPipPip
  • 162 posts
  • Cinematographer
  • Maryland

Posted 17 June 2016 - 09:59 PM

Yes, the haze will of course scatter the light resulting in visible shafts of the beam.  You might want to try coming in from a high angle to hide the beams as they are most obvious when viewed on axis.  Also coming in from a longer distance so the angle of the beam is not as dramatic will make it less defined than if you use a wide angle lens on the projector and can clearly see the cone of the projection. 

 

But the reality is projectors just arn't super bright so if you have some other lights flickering on the haze for the glow of fire it will really make it hard to tell there is projected images.


  • 0

#6 Mark Dunn

Mark Dunn
  • Basic Members
  • PipPipPipPip
  • 2182 posts
  • Other
  • London

Posted 18 June 2016 - 05:30 AM

 

But the reality is projectors just arn't super bright so if you have some other lights flickering on the haze for the glow of fire it will really make it hard to tell there is projected images.

I think you may be discounting the effect of the Scotchlite screen. The gain is 1000:1. Stray light won't affect the retroreflection very much at all because it's off-axis.


  • 0

#7 Shawn Sagady

Shawn Sagady
  • Basic Members
  • PipPipPip
  • 162 posts
  • Cinematographer
  • Maryland

Posted 19 June 2016 - 03:34 AM

I think you may be discounting the effect of the Scotchlite screen. The gain is 1000:1. Stray light won't affect the retroreflection very much at all because it's off-axis.

 

Oh you misunderstood, it wasnt that you wouldnt be able to see the screen, that will be fine, I was saying you could sort of hide the beam/shafts from the projector in the haze by hitting the haze with some other light like flickering amber or something since its supposed to be a fire.


  • 0



CineLab

Pro 8mm

Willys Widgets

rebotnix Technologies

Glidecam

Ritter Battery

Technodolly

Broadcast Solutions Inc

Zylight

Tai Audio

Metropolis Post

Aerial Filmworks

Paralinx LLC

Abel Cine

CineTape

Visual Products

The Slider

Rig Wheels Passport

CineTape

Metropolis Post

rebotnix Technologies

Visual Products

Rig Wheels Passport

Paralinx LLC

CineLab

Ritter Battery

Glidecam

Aerial Filmworks

The Slider

Technodolly

Abel Cine

Willys Widgets

Pro 8mm

Tai Audio

Zylight

Broadcast Solutions Inc