Hi,
I’ve got some white PNG titles with alpha I’m using on a timeline which I need to add a slight blur to, but when I add a blur timeline FX to the png clip I’m getting black edges creeping in on the white text
Any way of avoiding this?
Thanks!
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Within the timeline …click on the Comp FX and → Segment Unpremultiplied should do the trick
Thank you! Unfortunately I’m already set to Unpremultiplied 
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Can’t do a screengrab, but yeah we’re set up the same here. OK, I’ll try a different file format maybe and see if that helps. Thanks!
Try using just the matte and filling it with a full white screen.
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In an Action on a timeline segment… a quick way to make the front solid white is to add a Duotone matchbox and make both colors white.
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This worked! Thank you all for your help, much appreciated
If you have Matchbook installed, use id_Premultiply before your blur, and set the Comp effect mode to Premultiplied.
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This is the correct way.
You must always be premultiplied to blur.
EDIT - remind me to file a ticket on MX-Premultiply On Black
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This also works a treat, thank you!
So to add…
I would always try to get supers from design dept as premult. It saves you step of having to premult it first like this to be mathematically correct. Changing the front to white works in a pinch, but its still extra steps you are stuck with.
Secondly, Im dealing with this right now… stacking id_Premults vertically cause some bug and your supers disappear. 2025.2.2 mac. I have 2 vertical segs of supers, both have id_Premult, an Action, and a Comp. If I turn off 1 of the id_Premults, the supers reappear but stacked, it wont work.
Soooo, just to have another method up your sleeve… but this method is teeeedious… you can enter the Modular Keyer in the timeline Action, change the start mode to GMask Tracer to cleanup the schematic, delete the Tracer, then use a Comp node to premult the front. You can save this as a Modular Keyer setup to load into other timeline Actions. Exit Modular and set the surface to Premult.
I wish i could eradicate unpremult supers from existence, but it seems to be the default from Adobe. Its a hassle to deal with and I dont think our clients want to be looking at all these jagged pieces of artwork either.
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Hmm, guess I’d have to see your actual clips/FX pipeline, but on the surface it seems to work OK for me, having multiple video tracks of an RGBA clip:
Both the highlighted clip and the one below it are setup with the same effects.
I suspect maybe something else is going on inside the Actions causing weirdness (which, as a side note, also make sure you’re setting the Surface inside the Action to Premultiplied, as it defaults to Unpremultipled… although that shouldn’t cause what you’re describing, )