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olaf steel
Ghost-like effect
on Mar 24, 2011 at 2:29:26 pm

Hi,

This may have been covered elsewhere, if it has, please direct me to where that post is.

I want to create a sort of ghost effect where one of the actors looks almost transparent. To do this, I shot all my scenes twice without moving the camera for each shot. The first shot would have the actors who are not supposed to be ghosts doing their thing, then the second time I shot it again with just the ghost, keeping exactly the same setup.

I thought that I could just bring them both into FCP, lower the opacity of the ghost clips, and then place them above the other clips on the timeline. However, when I do this BOTH clips somehow are transparent. How do I get around this?
I would like to do this all in FCP, avoiding any other apps, like AE or Motion as I am doing an offline edit.

Thank you in advance for your help.


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Dave LaRonde
Re: Ghost-like effect
on Mar 24, 2011 at 3:14:22 pm

[olaf steel] "I would like to do this all in FCP, avoiding any other apps, like AE or Motion as I am doing an offline edit."

Um, better planning when you shot? This sort of situation comes up all the time on the After Effects forum. So With a tip of the hat to Shane Ross for the idea, plus a key contribution from David Roth Weiss, here's a cut 'n paste response:


Dave's Stock Answer #2:

When you're out on a shoot, and you say, "we'll fix this in post" without knowing PRECISELY HOW you're going to fix it in post, don't shoot it! You'll only end up shooting it over again.

Since post typically costs three times the cost of production, fixing something in post is not a way to save money, but rather a way to spend more of it.

And, before you say "well fix it in post," always consider who's doing the work, especially if you're the one doing the work.

Dave LaRonde
Sr. Promotion Producer
KCRG-TV (ABC) Cedar Rapids, IA


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Bret Williams
Re: Ghost-like effect
on Mar 24, 2011 at 6:30:06 pm

[Dave LaRonde] "Since post typically costs three times the cost of production, fixing something in post is not a way to save money, but rather a way to spend more of it."

Maybe. But I'm constantly telling producers if they had shot another day to get so and so shots, then we wouldn't be having to get all creative in post. They like to remind me that a crew of 5 people on a shoot, all at 500 plus a day is a hell of a lot more expensive than an extra day in post at 500 plus a day.


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Dave LaRonde
Re: Ghost-like effect
on Mar 24, 2011 at 6:38:31 pm

[Bret Williams] "...a crew of 5 people on a shoot, all at 500 plus a day is a hell of a lot more expensive than an extra day in post at 500 plus a day."

True, but typically such crews also know to do things like shoot clean plates if in doubt, record room ambience, and leave tough effects shots to others.

If they don't, that's a pretty good gig you got going, fixing all those mistakes. Make 'em pay for their lack of foresight.

Dave LaRonde
Sr. Promotion Producer
KCRG-TV (ABC) Cedar Rapids, IA


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Bret Williams
Re: Ghost-like effect
on Mar 24, 2011 at 8:13:49 pm

Not really referring to the ghost like effect. Just in general. You know, I saw this effect once on Family Guy when Peter dies and leaves his body. I wonder how they did it? Green screen?


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Simon Webb
Re: Ghost-like effect
on Mar 24, 2011 at 3:45:25 pm

Well, I'm going to assume that your ghost character doesn't overlap the space that your non-ghosts take up. If that is the case, then using a garbage matte around your ghost should do the trick. If it isn't the case, then hours of rotoscoping in After Effects is one possible answer.



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olaf steel
Re: Ghost-like effect
on Mar 24, 2011 at 4:04:15 pm

For the most part they don't overlap.
I don't understand why it doesn't work when I place the ghost clip over the other clip and then lower the opacity of the ghost clip. Perhaps someone could explain this to me so I can get a better idea of how to approach this. Usually I avoid leaving this sort of thing to figure out in post, but in my head it seemed so simple, like doing the technique I described above in Photoshop.


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Dave LaRonde
Re: Ghost-like effect
on Mar 24, 2011 at 4:41:02 pm

[olaf steel] "I don't understand why it doesn't work when I place the ghost clip over the other clip and then lower the opacity of the ghost clip. "

Because your original background is STILL THERE. Since it's a locked-down shot, that still-present background is over the other talent, even if it's at a reduced opacity.

You need to eliminate that background on the upper clip. There are a few ways to do it:
  • Rotoscope it out, a very painstaking, frustrating and time-consuming process, totally out of the FCP's capabilities
  • Re-shoot the ghost on a chroma key background, key out the background and reduce ghost opacity... did you save measurements of the distances of ghost to camera and placement of the other talent, and do you remember the focal length to which you set the zoom lens? Do you remember how high the camera was in relation to the set and talent? Depending on your camera, this could be something of a crap shoot.
  • Re-shoot the ghost on a black background, and use an FCP blend mode like Add, Screen, or Overlay. The same admonitions above about setting up the camera properly still apply. And it would be good to run a test to see if it would work at all.

This is why people plan how they're going to do special effects, and think long and hard about them.

Dave LaRonde
Sr. Promotion Producer
KCRG-TV (ABC) Cedar Rapids, IA


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Scott Sheriff
Re: Ghost-like effect
on Mar 24, 2011 at 5:14:52 pm

Dave,
"This is why people plan how they're going to do special effects, and think long and hard about them."

When did it become the norm to shoot VFX without doing test shots?
I must have missed that.

Scott Sheriff
Director
http://www.sstdigitalmedia.com

I have a system, it has stuff in it, and stuff hooked to it. I have a camera, it can record stuff. I read the manuals, and know how to use this stuff and lots of other stuff too.
You should be suitably impressed...


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Dave LaRonde
Re: Ghost-like effect
on Mar 24, 2011 at 6:17:53 pm

[Scott Sheriff] "When did it become the norm to shoot VFX without doing test shots?"

If I had to guess, it was about the time someone came up with a show (and movie) like Jackass.

In last summer's A-Team movie, there's a line from Murdoch as he's piloting a helicopter: "Hold on guys, I'm gonna try something I saw in a cartoon once!"

They all seem to spring from the same mindset. Actually, it's pretty much the same mind set. In looking over the OP's history, he has a knack for shooting first and hoping for a miracle later.

Dave LaRonde
Sr. Promotion Producer
KCRG-TV (ABC) Cedar Rapids, IA


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Mark Suszko
Re: Ghost-like effect
on Mar 24, 2011 at 7:37:16 pm

Hey, Olaf, I'm going to take a stab at your problem. I am thinking what you want to do is first lock the bottom track in full opacity, then put your track with the "ghost" on the next-highest video track. The part you may be missing is, change the "blend mode" of the top clip. Look under Modify>compositing modes, then way at the bottom of that drop-down menu you have numerous choices. Play with a combination of the composite mode and opacity settings for the clip, and I think you may get close to your goal.

If you decide you need to get rid of the background in the clip containing the ghost, you can try what's called a "difference Key". This is what isight webcams use to cut you out of the background and layer you into footage of riding a roller coaster or whatever. It will not be as clean as a chromakey, but requires no reshoots.

Beyond that, you can use the 8-point or 12-point masking tool and keyframe it relatively tightly around the ghost, feather the edges of that mask, THEN play with opacity and blend modes again.


Good luck, don't give up. Like me, use the "guess-and-press" method until you get what you want. Works for most things, but not 747's:-)


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olaf steel
Re: Ghost-like effect
on Mar 24, 2011 at 8:13:08 pm

Thanks a lot for that Mark.
I'm not at my editing computer right now, but I'll try it tonight. I appreciate you trying to help out as I do already know that better fore-planning would have ensured I avoid this mess, as other people have been saying.

I'll post back with how things went.

Thanks again. Truly appreciate it.


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Mark Suszko
Re: Ghost-like effect
on Mar 25, 2011 at 8:33:39 pm

So Olaf, how's it going?


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olaf steel
Re: Ghost-like effect
on Mar 26, 2011 at 6:19:11 pm

Thank you for your tips, Mark. I just started trying them today. Its working, its just a matter of trial and error, as you said. So far the best results have come from selecting "Multiply" in the "Composite" modes section. Then I have added an 8-point garbage matte around the ghost, leaving enough space around the edges for movement so I don't have to keyframe it too much. Then I've feathered it almost to 100 because of the difference in color between the layers, because where they overlap, the colors obviously become darker.
Do you think there is a way that I can somehow color correct the ares not covered by the mask? Possibly darken them somewhat?

I definitely think I'm on the right track though. Luckily the ghost and the other actors never overlap.

I couldn't figure out how to use the "difference Key" though. It doesn't seem to make a difference really.

Again, thank you so much for your help. This is much lighter work now.

Olaf


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olaf steel
Re: Ghost-like effect
on Mar 26, 2011 at 6:41:31 pm

I have just found what I think I'll use. I'm going to put a little more distance between the ghost and the main character that is not a ghost.

First I reduced the opacity of the ghost layer to about 60, then I'm added an Image Mask to the ghost layer and made it so that it covers the area around the ghost, leaving enough space around it to move around. As the ghost is walking forwards, I have keyframed the mask to follow the ghost.
As I mentioned before, there is a problem with the lighting - it's darker where the layers overlap. So, I added a mask feather to the ghost layer and feathered it almost to 100. Now there is no noticeable difference between the two layers.


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