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Jessariah67
Jessariah67
Known Participant
April 11, 2023
Answered

Shadow artifacts on text fade ins and outs

  • April 11, 2023
  • 5 replies
  • 603 views

I've been having some issues with text hving just a hair of an outline on and off, but now I have a render (with an alpha channel) where the text is almost "ghosting" as it fades in and out. When I have it playing over the scratch video in AE or the transparent checkerboard, everything fades in and out just fine. But as an overlay, it is ghosting a black shadow of the text as it comes in and as it fades out. Not sure how else to descrive it.

 

Any help would be appreciated!

This topic has been closed for replies.
Correct answer Thaumar

Did you render straight alpha or pre-multiplied? Make sure when importing the render to match the alpha interpretation with the render setting. 

Straight alpha would be best in most cases, but the render might look weird when playing back in a player only showing RGB and not taking the alpha in account. When imported, with straight alpha interpretation, in an application (like After Effects or an editing application for example) the result should match the result in the After Effects comp. 

5 replies

Jessariah67
Jessariah67Author
Known Participant
April 12, 2023

That was it - As soon as I changed the Alpha to "Premultiplied (dirty)," it went away! It was there with both "regular' Premultiplied and Straight. I remember having to use that setting to clean up some christmas snow alpha clip once. 

 

Anyway - thanks everyone for the hlep!

Jessariah67
Jessariah67Author
Known Participant
April 12, 2023

EDIT: There is no shadow at all on the text. I am supplying a shoret clip with the example. You can see that the "thumb" doesn't "ghost" like the white text does. 

 

https://vimeo.com/harkproductions/review/816825971/a5c80ef90d

 

This is an alpha overlay I brought into my NLE. If I fade the overlay out within my NLE, the text doesn't ghost like that, so it's not an artifact being generated in the NLE - it's being rendered into the file (I built the file in AE over a scratch of the base video - and it does not "ghost" in the AE work file, either - just in the render.

Thaumar
ThaumarCorrect answer
Inspiring
April 12, 2023

Did you render straight alpha or pre-multiplied? Make sure when importing the render to match the alpha interpretation with the render setting. 

Straight alpha would be best in most cases, but the render might look weird when playing back in a player only showing RGB and not taking the alpha in account. When imported, with straight alpha interpretation, in an application (like After Effects or an editing application for example) the result should match the result in the After Effects comp. 

Mylenium
Mylenium
Legend
April 12, 2023

If the shadow is generated with a layer style, it will pop in and out due to how that stuff works based on thresholds. If that's the case simply replace it with a proper effect that inherits layer transparency instead of doing its own thing. Otherwise indeed more info is required.

 

Mylenium

R
Community Expert
Rick GerardCommunity Expert
Community Expert
April 12, 2023

If the text is small, then it could be just position artifacts. Without a screenshot showing the modified properties of the problem layer (press 'uu') and a detailed workflow description, it's pretty difficult to diagnose problems. 

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