Keyed green screen appears during Cross Dissolve...

Hi all, the subject tells the story.

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

The keying was effortless and the results look good, but about 40% of the time when I do a dissolve or a cross dissolve of the keyed woman, I see a ghost image of the green screen during the transition.

Any thoughts or pointers on this one?

Thanks a bunch,
Matt

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

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

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

Hi Scott,
I am using FCP 6.0.1

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

"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
- - - - - - - - -

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.

By the way, nesting the layers, then adding dissolve does not seem to work.

For a fade to black, I add a black color matte layer and manually keyframe it's opacity.

However, I still have no work around for cross dissolves...