Banding with alpha assets in Premiere

[Multipasser]

it's driving me crazy why perfect straight alpha exports give banding in Premiere.

Lot of the time I deliver assets to editors or tv stations with alpha channels.

Many times there is some kind of flare/glow on a text or asset layer.

the only way to get rid of this is to turn this off.

But what if an editor does not want to do this, because it changes other things in the timeline?

Do I need to interpret the files different in order to get rid of the banding?
I tried 16bit and 32bit. Same result. Only the 'composite in linear color' checked off does the trick.

This is the ugly banding you get on soft glows in Premiere.

While it should be like this:

should be like thisalpha png

[R Neil Haugen]

How are you creating the alphas?

[Multipasser]

With after effects. 
Any straight alpha gives this result. 
No matter what fileformar.  Qt lossless. Qt 4444 ProRes. PNG alpha.  The all do the same. 

[R Neil Haugen]

Have you tried remultiplying?

[Averdahl]

I have never seen or heard that turning off Composite in Linear Color gives any other issues. What i have seen and heard for years is that having it enabled (default) gives issues such as the one you describe.

I have disabled Composite in Linear Color in all timelines for years and have had no other issues realted to this setting.

I have never seen a solution for those issues you have, so just disable Composite in Linear Color is, imho, the best way to solve issues like this. Premiere Pro has no issues when the opacity is either 0 or 100 but it has issues when the opacity is anything between 0 and 100. It has unfortunately been like this since CS5 and only a few times during the years it has been fixed, until a new version of Pr is released. The last time it was fixed was probably a decade ago...

the only way to get rid of this is to turn this off.

But what if an editor does not want to do this, because it changes other things in the timeline?

By @Multipasser

[Multipasser]

Thanks. Odd it is still an issue since CS5.

I hope they fix this because it is annoying.

Don't know yet about what issues they get when disabling.

So what does that button do? Just use GPU for compositing? That's it?
Maybe other plugins that use GPU's and suddenly are forced to use CPU can give other results in color or effects.
I'm just thinking out loud. 

But if they complain about the banding I know it is a known PR issue and the only fix is to turn the button of!

thanks

[R Neil Haugen]

Averdahl is a very experienced long-time user professionally. So his comment that he has never heard of any issue from turning of f"composite in linear color" is quite accurate for everything up through network deliverables.

That is only needed for certain things, I'm not even sure what because I've never needed one. Maybe EXR comps or something like that, very unusual for most editors to deal with.

The other thing is you didn't say whether the alpha was pre-multiplied or not. Premiere doesn't give options for alpha handling but defiinitely prefers the pre-multiplied form. If not pre-multiplied, you need to turn off composite in linear color.

Which most of us just leave off period.

[Multipasser]

Thanks

I Always render straight alphas. Will try premultiplied. But you get ugly results with glows and flares or I need to use mattes and render the straight alpha flat. That's better that gives you basically the same result as a straight alpha. 

[Tom_edit]

Disabling linear color can introduce some issues, most notibly with things like the dissolve transition where it will no longer gradually step in opacity and will suddenly jump in opacity in the initial stages of the transition (can also cause issues if you dissolve a layer above another layer I think..? or something like that?) I saw a video a while back now that explained this a bit better than I can paraphrase but unfortunately after 30min of digging I can't find it again 😕

[Averdahl]

Are you sure? 🙂

The problem you mention happens when Composite in Linear Color is enabled and goes away when one disable it.

Disabling linear color can introduce some issues, most notibly with things like the dissolve transition where it will no longer gradually step in opacity and will suddenly jump...

By @Tom_edit