Creating Alpha Channel please help

[Steve Roberts]

1. Your composition has to have a transparent background. In other words, the frame should not be completely filled. To check, hit the checkerboard button at the bottom of the comp window. Your white text should be a Text layer or if the Basic Text effect was applied to a solid, then “composite in original” or similar should be selected in the Basic Text effect controls.

2. You need to render using “make movie” to open the render queue. In the Output Module, you need to render to a file format or codec that supports alpha channels. Examples are 32-bit TGA, PSD, PNG, and Quicktime Animation codec.

3. Also in the output module, you need to select RGB+alpha and millions+.

For the boxer, you might need to apply one of AE’s keying effects to key out the black, or interpret the boxer footage (select the boxer in the project window, then file>interpret footage>main) and select “straight alpha” or “premultiplied alpha” if available.

Does that help?
Steve

[Espnetboy3]

Yes thank you i will try this. Although i realized the boxer did have to be keyed. I used the basic color key but I messed with the color difference and there were 3 types of eyedroppers, what do they each do? There was no plus or minus just like on a quarter filled on half filled and one empty it looked like. Also, do i need to make my text on a solid and the solid has to be a totally diff color than wat is in my text correct, or else the alpha channel wont work?

[Steve Roberts]

The Color Difference Key is very complex, and the best explanation for it is contained in Trish and Chris Meyer’s Creating Motion Graphics, Volume 2. I recommend you avoid it and consider Keylight, included on the install CD pf recent versions of AE. The docs for keylight should be on the CD.

However, since the boxer is probably on a solid black BG, AE’s Color Key should do fine.

Regarding the text, my original instructions were backwards: you should leave “Composite On Original” unchecked in the effect controls. My apologies.

Steve

[Michael Hancock]

If you got the boxer from ribbitfilms.com like you said, you should have been able to download a matte for it as well. If you didn’t download the matte, go download it now. We’ll wait! 🙂

Now, once you get the matte, put it on a layer above your boxer and make sure both clips start at the same point in your timeline. Then select Track Matte on the actual footage of the boxer (the lower layer with the actual boxer, not the layer with the black and white version of the boxer–that’s the matte you’re going to track). Set it to Luma Matte, or possibly Inverse Luma Matte or whatever it’s called (I’m not in front of AE right now and I’m tired). This will create the perfect key for the boxer since ribbitfilms already did it for you.

From there you should be ready to rock and roll. If you need to resize the boxer or do anything crazy to him like rotate or put into 3D space, precompose your boxer layer and the track matte layer. Then any resizing your do will affect both. Good luck, let me know if this helps.

Michael.

As far as text goes, do exactly what Mr. Roberts suggested and you’ll be rockin’ and rollin’ in no time.

[Espnetboy3]

Very cool Michael thanks for the help everyone. It did come with a matte layer I didnt realize one would need it. What is this precomping stuff? I hear people talking about it , that is saves time or doing a quick render instead of full?

[Steve Roberts]

Look up “precomposing” in the help.

Basically, you do it when you’ve created layer X inside composition A, and you want to turn that layer X into a comp B nested inside comp A. You precompose layer X and call it Comp B. If you then look inside comp B, you’ll find layer X there.

Nesting is the same thing, but in that case, you create comp B, create layer X inside it, then drag comp B into comp A.

There can be many organizational situations where it is useful, but it is necessary when you use an effected layer X as a layer map for an effect applied to layer Y. The layer Y effect looks to the original layer X as a layer map, before the layer X’s effect was applied. So you need to precomp layer X so the Y effect sees the comp with the effect inside.

An example would be applying the displacement map effect to layer Y, and using a fractal noise layer X as the displacement map. You’d need to precomp layer X so the dispmap effect can actually see the fractal.

Experiment.

Steve

[Espnetboy3]

Thanks you guys are great. I have the creating motion graphics book I need to read it in full. I do some vfx work with shooting background plates and using masks but I would like to go to the next level.