Green screening a spray of tiny clear objects at DVinfo.net

Steven Hoffman · July 24th, 2010, 11:41 AM

I'm trying to make it look like clear crystals are shooting out of a persons ear.

I'm thinking that using a green screen and a hose full of plastic crystals that we can get them shooting out in the desired way, however, I'm not sure if its possible to film them from a distance and not have them completely key out when its time to remove the background.

I'm then thinking of simply using the footage, keyed out, over footage of the subject.

I know its an odd request, but does anyone have any ideas I can try? Is green screen a bad idea for something like this?

Panasonic AG-HVX 200
Green screen,
3 Tota Omni's, and a pro
and around $100 spending money.

Shaun Roemich · July 24th, 2010, 11:49 AM

IF this is possible, I'm going to suggest that a STRONG backlight might be the "key". (Pardon the pun...)

Probably easier to try and find pre-keyed material or CG it yourself...

Dano Motley · July 24th, 2010, 01:20 PM

go to digital juice dot com and check their compositers tool kit. might already have it done for you?

Dano

Dean Sensui · July 24th, 2010, 02:09 PM

Primatte can do this. I've keyed transparent plastic packaging -- the kind that requires a chain saw to open after you bought something like a CF card or similar.

There are several things that need to be carefully set up. One is the green screen -- expose it at 50 IRE. Another is the camera -- do not use any odd matrix setups. You'll want that green to be green. Try to eliminate any sharpening that will create edge artifacts. And shoot only in progressive mode, not interlaced. Of course it should be in 1080 p30 HD.

The HVX can shoot a nice key. I've done it before.

As Shaun suggested, you can use a backlight. While Primatte can key without the backlight, using a point source as a backlight will get the crystals to sparkle. Be aware that any lighting you use on the crystals will also have to make sense in your master shot or it'll look out of place.

OR you can use particle effects if you have After Effects. The advantage is that you can animate it to do almost anything you want, and you can play around with it until you acheive the effect you're looking for.

Bill Davis · July 25th, 2010, 01:56 AM

Another vote for After Effects or Apple's Motion.

Both do particle effects so easily that you should be able to get something with an alpha channel that you can composite over an existing shot in short order.

July 24th, 2010, 11:41 AM	#1
Steven Hoffman Regular Crew Join Date: Oct 2006 Location: Buffalo, New York Posts: 51	Green screening a spray of tiny clear objects I'm trying to make it look like clear crystals are shooting out of a persons ear. I'm thinking that using a green screen and a hose full of plastic crystals that we can get them shooting out in the desired way, however, I'm not sure if its possible to film them from a distance and not have them completely key out when its time to remove the background. I'm then thinking of simply using the footage, keyed out, over footage of the subject. I know its an odd request, but does anyone have any ideas I can try? Is green screen a bad idea for something like this? Panasonic AG-HVX 200 Green screen, 3 Tota Omni's, and a pro and around $100 spending money.

July 24th, 2010, 11:49 AM	#2
Shaun Roemich Inner Circle Join Date: Sep 2002 Location: Vancouver, British Columbia (formerly Winnipeg, Manitoba) Canada Posts: 4,088	IF this is possible, I'm going to suggest that a STRONG backlight might be the "key". (Pardon the pun...) Probably easier to try and find pre-keyed material or CG it yourself... __________________ Shaun C. Roemich Road Dog Media - Vancouver, BC - Videographer - Webcaster www.roaddogmedia.ca Blog: http://roaddogmedia.wordpress.com/

July 24th, 2010, 02:09 PM	#4
Dean Sensui Inner Circle Join Date: Oct 2001 Location: Honolulu, HI Posts: 2,054	Primatte can do this. I've keyed transparent plastic packaging -- the kind that requires a chain saw to open after you bought something like a CF card or similar. There are several things that need to be carefully set up. One is the green screen -- expose it at 50 IRE. Another is the camera -- do not use any odd matrix setups. You'll want that green to be green. Try to eliminate any sharpening that will create edge artifacts. And shoot only in progressive mode, not interlaced. Of course it should be in 1080 p30 HD. The HVX can shoot a nice key. I've done it before. As Shaun suggested, you can use a backlight. While Primatte can key without the backlight, using a point source as a backlight will get the crystals to sparkle. Be aware that any lighting you use on the crystals will also have to make sense in your master shot or it'll look out of place. OR you can use particle effects if you have After Effects. The advantage is that you can animate it to do almost anything you want, and you can play around with it until you acheive the effect you're looking for. __________________ Dean Sensui Exec Producer, Hawaii Goes Fishing

July 25th, 2010, 01:56 AM	#5
Bill Davis Trustee Join Date: Jan 2004 Location: Scottsdale, AZ 85260 Posts: 1,538	Another vote for After Effects or Apple's Motion. Both do particle effects so easily that you should be able to get something with an alpha channel that you can composite over an existing shot in short order. __________________ Classroom editing instructor? Check out www.starteditingnow.com Turnkey editor training content including licensed training footage for classroom use.

July 24th, 2010, 01:20 PM	#3
Dano Motley Regular Crew Join Date: Jul 2009 Location: Montclair New Jersey Posts: 101	go to digital juice dot com and check their compositers tool kit. might already have it done for you? Dano