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tga+alpha + opacity

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Nacho Jiménez
tga+alpha + opacity
on Dec 3, 2010 at 12:58:30 pm

I need to make a transparent "base for writing" for a tv program.

If I make a square mask in a red layer, set opacity to 50, and render in tga+alpha (need it in this format) I have to set the background color to the same red color as the red layer, if not the square will turn lighter (if bkgrn is set to white or darker if it's black).

If it's not a solid color (ramp) or I use a red square and a blue circle with 50% opacity both I have a serious problems.

Also there are problems with the edges in this type of pieces, when using curved or diagonal shapes or feather the edges.

¿Is there any way to solve this problem?

¿Can I render with a "border of colour" for every layer of my comp or use an image as background?

The problem is bigger if I animate the pieces.

(Using "latest version" ae 5.5 at work.........) :p

Thank you

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Dave LaRonde
Re: tga+alpha + opacity
on Dec 3, 2010 at 4:30:05 pm

I'm confused by what you need. Do you need a semi-transparent red square with a border? I suggest you add a video layer for reference only to see what it will look like, then remove the video layer when you're ready to render.

You can put a border on your mask with the Stroke effect.

Dave LaRonde
Sr. Promotion Producer
KCRG-TV (ABC) Cedar Rapids, IA

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Kevin Camp
Re: tga+alpha + opacity
on Dec 3, 2010 at 5:44:00 pm

i what you are looking for is in the output module settings (from the render queue). when you output a file with an alpha, there are two ways to produce the rgb (or color) portion of the file: premultiplied or straight (unmatted).

you want to choose 'straight (unmatted)' so the translucent areas of the file do not get premultiplied with the background.

for more info on this check out this page from the manual (it's a newer version, but it still applies to 5.5):

and this tutorial also does a good job of explaining this:

Kevin Camp
Senior Designer

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