Transparency Bug?

Adobe After Effects

Transparency Bug?

Posted by Christopher Kelly on February 4, 2015 at 6:48 pm

Hey all,

not sure why I am just noticing this. Strange bug that is happening to me, wondering if there is a solution.

I have tested it pretty well and it always seems to happen if I ‘create’ transparent aspects on a clip, it makes other areas on the clip transparent that should be completely opaque.

For example, if I create a square mask on a clip, there is a slight transparency within the square. It is very slight, I only really notice it with a hard edge, like a line or the border of another layer.

It also happens to me when I use a layer or shape layer as an alpha matte.

The clip is full opacity, so I know it is not that. And if I delete the mask or get rid of the alpha, that slight transparency is gone.

It is a really slight transparency, it is only really noticeable if there is movement. I create a new layer, drag it under my clip that has a square mask on it, and drag the layer underneath up and down, and see a line that crosses my clip and slightly changes the color.

There is no blending mode, no dropped opacity, no alpha matte (though it has the same issue with an alpha matte) so there should be no change in transparency. Hope this makes sense, any help is appreciated.

Walter Soyka replied 11 years, 7 months ago 2 Members · 10 Replies
10 Replies

Walter Soyka
February 4, 2015 at 8:54 pm

Can you post a screenshot and maybe an AEP?

I’m thinking it might be either motion blur or sub-pixel sampling if it’s happening at the edges, but it’d be helpful to see what you’re seeing.

Walter Soyka
Designer & Mad Scientist at Keen Live [link]
Motion Graphics, Widescreen Events, Presentation Design, and Consulting
@keenlive | RenderBreak [blog] | Profile [LinkedIn]
Walter Soyka
February 4, 2015 at 11:47 pm

[Dave LaRonde] “You should have been a spy, Walter. In that new picture, you don’t look a bit like the last couple of shots you’ve used.”

Ha ha! This might be the first time I haven’t been rocking sunglasses in a profile picture.

[Dave LaRonde] “It’s got a certain ring to it: Walter Soyka, Master Of Disguise…..”

That sure does sound better than Walter Soyka, Ten Years Older!

Walter Soyka
Designer & Mad Scientist at Keen Live [link]
Motion Graphics, Widescreen Events, Presentation Design, and Consulting
@keenlive | RenderBreak [blog] | Profile [LinkedIn]
Christopher Kelly
February 5, 2015 at 4:09 am

Hey Walter,

Thanks for your reply,

here is a box drawn with the rectangle tool on a clip, with a simple color layer offset underneath it.

do you see that line that goes across, at the top edge of the layer?

Now here is the same shot, nothing changed, except deleting the mask that is on the clip.

the line is gone, which leads me to believe that somehow, just a basic mask is causing some kind of transparency? Definitely not motion blur, nothing is moving. No effects are on it, no keying, no alpha. ideas? I tried this on a mac (I am on a pc) and did not see it happening.
Walter Soyka
February 5, 2015 at 4:14 am

Christopher, I’m having a hard time seeing. Can you upload a PNG instead of a JPG (the compression artifacts make critical evaluation hard!), and maybe add a pointer to where I should be looking?

Walter Soyka
Designer & Mad Scientist at Keen Live [link]
Motion Graphics, Widescreen Events, Presentation Design, and Consulting
@keenlive | RenderBreak [blog] | Profile [LinkedIn]
Christopher Kelly
February 5, 2015 at 4:19 am

So in the red circle, there is a line that goes across from the top of the grey solid and is slightly visible on the clip.

could it be my monitor? I know monitors can vary the color of footage quite a bit, but can’t imagine why mine would be making me see ghost lines..

here is without the grey solid, line is gone
Walter Soyka
February 5, 2015 at 4:24 am

[Christopher Kelly] “could it be my monitor? I know monitors can vary the color of footage quite a bit, but can’t imagine why mine would be making me see ghost lines..”

I think it might be. Easy enough to test: scale that gray solid down so it fits fully behind the foreground clip. When the background solid longer extends beyond the edges of the foreground clip, does the line disappear?

Walter Soyka
Designer & Mad Scientist at Keen Live [link]
Motion Graphics, Widescreen Events, Presentation Design, and Consulting
@keenlive | RenderBreak [blog] | Profile [LinkedIn]
Christopher Kelly
February 5, 2015 at 4:30 am

yes! Huh. I need to go watch some of my exports on a different computer. I kept thinking it was a keying error and tried everything possible to get rid of it.
Thanks for your time, Walter!
Walter Soyka
February 5, 2015 at 4:31 am

Glad we got it sorted. Out of curiosity, what’s the make and model of your monitor, and how is it connected?

Walter Soyka
Designer & Mad Scientist at Keen Live [link]
Motion Graphics, Widescreen Events, Presentation Design, and Consulting
@keenlive | RenderBreak [blog] | Profile [LinkedIn]
Christopher Kelly
February 5, 2015 at 4:39 am

Its an Asus VH238H connected through what I think is just an ordinary VGA cable, except the input to the computer has to go through an adapter to what I think is an SVGA input.

which sounds a little silly, but that is how I got the computer.
Walter Soyka
February 5, 2015 at 6:34 am

The artifacts you’re seeing are consistent with analog VGA. Switching to a digital connection like DVI or HDMI should help.

Walter Soyka
Designer & Mad Scientist at Keen Live [link]
Motion Graphics, Widescreen Events, Presentation Design, and Consulting
@keenlive | RenderBreak [blog] | Profile [LinkedIn]

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