View Full Version : Need help to the extreme!

03 March 2005, 02:53 AM

I have two questions.

First: I have recorded some effects against a black background. When I try to place this effect layer on another video layer as a background, there is no blending in After Effects! I can't get it to work. To make things worst, the Alpha under Interpret Footage is greyed out. So sad. I got this cool fireball against a black background (in miniDV avi format) and I don't know how to composite it (first time to do something like this). I tried compositing using Premiere or Vegas, it doesn't look right (probably cause I am doing something majorly wrong)since the fireball is semi-transparent and lacking depth in color. This project is harder that it should be! I read that After Effects should be able to do this properly with Lumicenct Premultiply but it ain't working! Help please!!!

Question two: I also have the firstball against the black background, and I want to composite this into Photoshop on a stationary background. I also can't get blending to work here also. I am soooo confused with transparencies..... It would be nice if someone could help me understand this better (with words or links to external websites).


03 March 2005, 05:41 AM
The reason why your alpha selection is grayed out when you bring the footage into AE is because your footage has no alpha channel. Shooting any footage using a DV cam will never yield an alpha channel. You must either key out the black background or rotoshape the fireball to seperate the fireball from the background so that you can composite it onto another background.

Read through AE's docs on keying and roto-ing.


03 March 2005, 10:08 PM
hi or else u can also use screen mode in after effects but the foreground might be visble slightly so try to duplicate the layer and use screen even for the duplicated layer.

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03 March 2005, 10:08 PM
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