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More black backdrop problems

Posted: Wed, 19th Jan 2005, 9:05am

Post 1 of 4

silencer

Force: 250 | Joined: 5th Jan 2005 | Posts: 184

Windows User FXhome Movie Maker

Gold Member

Hi, when using things with black backdrops in Chromanator, i right click and choose add composite but the image becomes transparent. I've tried all the tool options and can't work this out. It happens with a white image on a black background and an image with black in it as well as the background. Any ideas guys

Silencer
Posted: Wed, 19th Jan 2005, 9:09am

Post 2 of 4

Simon K Jones

Force: 27955 | Joined: 1st Jan 2002 | Posts: 11683

VisionLab User VideoWrap User PhotoKey 5 Pro User MuzzlePlug User PowerPlug User PhotoKey 3 Plug-in User FXhome Movie Maker FXpreset Maker Windows User

FXhome Team Member

That is how the Add method is supposed to work. You should only use the Add method when compositing light-based effects, like a lightsaber, or an explosion. For anything else, you should use the Luminosity Key.

Of course, a black background isn't very efficient, it's generally far better to use an alpha channel (if it is a computer generated image) or greenscreen.
Posted: Wed, 19th Jan 2005, 9:14am

Post 3 of 4

silencer

Force: 250 | Joined: 5th Jan 2005 | Posts: 184

Windows User FXhome Movie Maker

Gold Member

sorry i'm new to all of this, whats an alpha channel and how would a create an image with one in a 3d package for use in chromanator
Posted: Wed, 19th Jan 2005, 9:21am

Post 4 of 4

Simon K Jones

Force: 27955 | Joined: 1st Jan 2002 | Posts: 11683

VisionLab User VideoWrap User PhotoKey 5 Pro User MuzzlePlug User PowerPlug User PhotoKey 3 Plug-in User FXhome Movie Maker FXpreset Maker Windows User

FXhome Team Member

An image traditionally has three channels - red, green and blue. By adjusting these channels you can derive any colour you want. An additional channel - the alpha channel - contains transparency information. By using an alpha channel, the computer knows exactly how transparent every pixel of the image should be - so you don't need to worry about keying the image at all. If you import an alpha-channelled image into Chromanator, it will automatically use the alpha.

Regarding using alpha channels in your 3D program, you should check out the program's manual.