Luma track matte

[fstof]

I'm trying to create a luma track matte in After effects, but it just wont work.
Here is what I've got:

layer1 - [black & white matte (gradient)] - (Normal)
layer2 - some text(Red) - (Luma track matte)
layer3 - background(whatever) - (normal)

What I am looking for is the red text (layer2) to appear as a gradient(defined by layer1) on top of the background (layer3)

The result is currently only red text on the background

Please help

[Matt Grunau]

A luma matte is going to act as an alpha channel. That doesn't sound like what you are wanting. You are wanting the text to have a gradient on it, or are you wanting the text to fade into the background? If you want a gradient on your text, you need to change you gradient to an appropriate blending mode and then use a copy of the text layer to act as an alpha track matte for your gradient.

Also, in your description, if the gradient goes from the top to bottom of the entire composition, and you text is not large, you aren't going to see much of a difference in the text itself. The gradient should only be as large as the height of the text.

[fstof]

Well, its not necaceraly text with a gradiant.
Specifically what I'm trying is to take some greenscreen footage, and making a matte (playing around with channels until my subject is white and screen is black - no alpha channel).
I then have 2 layers 1-Original and 2-matte then via the track matte trick get the screen removed.

I know keylight is the propper way to do this, but I am trying to do this manually

[dougspice]

So text actually has nothing to do with it? I don't hear anything actually wrong with your approach... and nothing wrong with learning to make your own keyer!

What's the actual problem?

[fstof]

correct, maybe text was not the best example :-)

The problem is that when I set the second layer to a "luma track matte" nothing happens... (I expect the black from the matte to remove the green from the original GS footage)
The first layer is set to hidden and then the rest of the comp is displayed with nothing keyed out, just the normal GS footage

Am I not understanding something here or is AE acting up?

[Matt Grunau]

Try precompising your top layer. And make sure they one you want to have used as a Luma matte is on top and hidden, with the bottom track (the original footage) set to Luma Matte.

And a more accurate description of what you are wanting initially always helps.


Hell, I thought you wanted cut out text with a gradient on top for a nice darkening effect.

[dougspice]

Might help to post a screenshot of your workspace.

[Matt Grunau]

Might help to post a screenshot of your workspace.

What he said.

[fstof]

Try precompising your top layer. And make sure they one you want to have used as a Luma matte is on top and hidden, with the bottom track (the original footage) set to Luma Matte.

And a more accurate description of what you are wanting initially always helps.


Hell, I thought you wanted cut out text with a gradient on top for a nice darkening effect.

By "precompising" I assume you mean putting it in a separate comp and then put that comp in the top layer???

I will give that a try.

As for the rest, its exactly the same (top layer is hidden, bottom original layer set to Luma matte)

I'll see if I can get a screenshot of my workspace later tonight

[fstof]

Okay, here are the screenshots. as you can see in the last one the blue was not pulled out.
I tried replacing layer1 (B&W) with a comp with the same image, still nothing

http://www.dustyvideo.co.za/images/stuff/matte.jpg
http://www.dustyvideo.co.za/images/stuff/screen.jpg
http://www.dustyvideo.co.za/images/stuff/background.JPG
http://www.dustyvideo.co.za/images/stuff/comp.JPG

[dougspice]

Hmm. That all looks correct to me, except possibly one thing I can't see because of the crop on the last image... are you certain that you're viewing the COMPOSITION, and not the footage of the individual TIFFs?

[milksac]

I'm with Matt on this. Try pre-comping the blue matte layer.

[fstof]

tried pre-comping the B&W layer, but did not change anything, will try doing it on the second layer.
And yes it is the comp view and not just the resource view.


This is really silly, I would think this is something pretty basic, but it turns out it is not

[fstof]

Sorted... I dont know why... I created a new projects and redone everything and voala... perfect

Thanks for the help everyone

[fstof]

Okay... now I actually know what the problem is. my preview was set to "OpenGL - Always On" and it looks like it does not reflect any changes done to the blending mode or the track matte selections