Keyed green screen appears during Cross Dissolve…

[Jeremy Garchow]

More info. How’d you do the key?

[Matthew Abourezk]

I used the “Blue and Green” key effect.

I tried the other key tools but had the most luck with this one.

Talkingbox Digital Media Group, Inc.
http://www.talkingboxdmg.com
(203) 327-6617

[Tom Matthies]

Is the effect rendered?
Tom

[Matthew Abourezk]

Hi Tom,

Not sure what you mean in asking if the effect is rendered.

When I have the clips stacked in the timeline, I render all, and play back. When playing back I see a ghost-image of the green screen appear during a cross dissolve transition.

Talkingbox Digital Media Group, Inc.
http://www.talkingboxdmg.com
(203) 327-6617

[Scott Robinson]

What version of Final Cut are you using? One of my students was seeing the same thing in FCP 4.5 using the same or the Chroma Key filter. I gave him some workarounds but that doesn’t answer the obvious question as to why it is doing that. Interested in hearing replies of others that experienced the same thing.

Scott Robinson
President
Take 2 Productions, Inc.
https://www.take2productionsinc.com

[Matthew Abourezk]

Hi Scott,
I am using FCP 6.0.1

Talkingbox Digital Media Group, Inc.
http://www.talkingboxdmg.com
(203) 327-6617

[John Pale]

Make sure all options, including the light and dark green ones, are selecting in your render menu.

if you have some odd combination of rendered and realtime effects you can get stuff like this.

if all else fails, select all the clips, toggle their visibility off and on to delete the render files…then try rendering again.

[Neil Ryan]

“I am doing cross dissolves of a person we videotaped in front of a green screen.”

What is happening on your background layer during this transisition?

I Find it best to do 1 of 2 things, depending on the composite:
If the backround stays the same during the FG transition, then put the 2 FG clips on separate layers and either use dissolves to fade one out as the other fades in, or adjust the Clips’ Opacity with keyframes.
If the background changes during the transition, make up two SEQs, one with one composite, one with the other; cut the two SEQs into your master SEQ and dissolve between them

Cheers,
Neil.

– – – – – – – – –
Neil Ryan
Post Production
The Pod Multimedia
http://www.the-pod.com.au
– – – – – – – – –

[Lee Berger]

I’ve had the same problem. I solved it by turning on shadow in the Motion tab. My project required a shadow behind the keyed subject, and I noticed the problem when I forgot to add shadow to a sequence. If you don’t want the shadow to appear try setting the x and y at zero or the opacity at zero.

Lee Berger
http://www.leebergermedia.com

[Denez Mcadoo]

I know this is an old thread, but I’m having this problem and have yet to find a good answer.

No one has really touched on it, but I think I know what is causing the problem (at least in my case).

As the opacity drops during the cross dissolve (or simple opacity drop), the key is calculating on the currently darker luminance range, the results change, and a different relationship between the two layers occurs.

I need a fix to this. My problem is that I do secondary color correction in FCP by duplicating the layer, keying out their face, and adjusting the lower layer. Cross dissolves result in the top layer fading in at a different rate then the bottom layer, and faces are visibly darker during this.