projecting video onto vapour
Posted 06 June 2005 - 08:04 AM
I'm visiting from the sister Steadicam Forum in search of some advice.
I'm to shoot some static B+W monologues, which are then to be projected onto a column of rising steam in a darkened space. Then I'll Steadicam shoot that from all angles. Has anyone any experience of doing this, or can anyone direct me to a previous discussion that my serching has so far failed to turn up?
Posted 06 June 2005 - 08:56 AM
Exposure? or smoke properties ( physical ones ) fi that, shooting in studio, air conditioning hitting the smoke might tend to "disperse"smoke.
Posted 06 June 2005 - 09:22 AM
My concern is general. I haven't done it before!
The plan is to project onto a column of rising steam, as smoke would disperse. Fraught with technical problems, I imagine.
Posted 08 June 2005 - 08:25 AM
I can offer (having never done this either!) a little, perhaps obvious advice.
You say you want to film the projection from all angles. To do this you will need to film it in 2 setups, one for each side of the smoke.
Smoke only picks up on film when it is backlit, so filming from the same side as the projector will get you nowt!
Are you projecting film or video?
If film, you will need it to be dual perf (if it's 16mm) so you can turn the film around in the projector to mimic the "other side" of the projection. If video, make sure you get a projector that has a rear projection mode, as this will reverse the image for you.
Shoot in a totally darkened room (or at least allow no light to spill onto the smoke other than the projector's lamp) - bear in mind that if you do want to light the room you will have to light to the exposure you get for the projector - I'd do some testing, if I were you!
If you get enough smoke in a fine enough plane (this will be difficult!), then you should get an image of *some* kind - obviously it'll be distorted and diffused to some extent - how much will depend on the volume and thickness of the smoke.
You might want to try, just thinking aloud here, shooting with a polarizing lens on your camera and "encasing" the smoke in two sheets of perpex or glass to help "wrangle" it into a fairly uniform sheet (there's a job no-one wants - smoke wrangler!). If you decide to go this route, then you may find that shooting from the front and back (perpendicular to the panes of glass) becomes unacceptable due to reflection, as the polarizer will be all but ineffective.
Hope that helps - if you shoot it, I'd love to see some frames, it's an intreaguing idea!
Edited by Dominic Jones, 08 June 2005 - 08:32 AM.
Posted 08 June 2005 - 08:45 AM
I don't know whether it was an in-camera effect or done in post, but I suspect the former - wasn't this done for the Seaquest TV series? Someone had an AI computer in his quarters which would manifest itself in a column of falling vapour. I seem to remember it only looked to be a couple of feet high.
Also, I'd definitely look at real dry ice rather than smoke. It's the densest, whitest, heaviest vapour you'll find in a common special effects shop and these are all characteristics that'll help you. Steam will rise but it isn't very dense, and heavy fog is grey, and doesn't fall as hard as dry ice. Even liquid nitrogen, which creates a very rapidly-falling mist, doesn't produce the thick white effect that dry ice does.
You might also talk to someone who's done water screen projection, which is a similar trick involving a spray of water. You tend to get a fairly obvious effect rather like a Photoshop radial blur, as all the light beams become visible radiating from the projector. I've seen it done from a barge on the Thames for a corporate event, it's a spectacular effect.
Posted 08 June 2005 - 10:30 AM
Posted 08 June 2005 - 11:28 AM
Posted 08 June 2005 - 12:44 PM
1. As has been mentioned, smoke/fog needs to be backlit or you won't see it.
2. Again, the fog is going to dissipate immediately unless held by something, and if it's not in a "sheet" as mentioned, but just a round puff of smoke rising up, it's going to deform and the image will just look like some light hitting the fog, not a recognizable image.
3. By "shoot from all angles" are you talking about a rotating shot all in one take? Or separate takes from different angles?
If you're trying to get the "3-D" look of whatever is being projected, then it will have to have been shot that way initially, and if you're moving around the column continuously, you would need a rig that the camera AND the backlight (on the opposite side of the smoke) are attached to, so they both rotate around the column at the same time/angle.
Maybe I'm way off here, so be specific about the look you need.