Glare node and alpha rendering

I’ve been having some major head scratching moments, trying to get a good output using glare nodes to render correctly for alpha output. I’ve searched through some old threads and it is discussed a few times, but I can’t seem to get what I’m after.

Basically I have a noodle with multiple glare nodes affecting different layers. It renders fine, with all effects displaying correctly.
I need to supply a version with an alpha channel, so the client can add there own background :mad:. The problem I am having is seeing the effects from the glare nodes, outside of Blender.
I’ve set output to RGBA. I’ve tried outputting with either straight alpha or premultiplied checked. I’ve completely reconstructed the noodle, separating the alpha from each glare node, checking it’s output individually ( fine ) and then using a set alpha node for each step. Major mission. I’m now getting a small amount of the effects showing through, but nowhere near how they should be.

The render layers all render and export correctly. It’s just the effects from the glare nodes which are missing. Any help would be greatly appreciated.


Bumping this up.
I’ve now had to change this animation completely and have a different set up, but would still interested in knowing what is up with the glare node effect, with respect to alpha channels…

To add to what I wrote above. Each effect group containing the glare node, has had alpha separated and checked. I’ve rendered out these individual elements and they looked okay ( in image editor ) It’s only when all the noodles are combined, that the problem starts to occur?

Not so easy to judge without seeing what you’re doing. Could you show us your setup?

Had similar problem with glare node in a video.

Looked fine when Composite was rendered, then rendered layers (3) out separately to be able to use sequencer adjustments on each layer, looked fine inside sequencer, but in final video glare objects were weak.

To correct I made a separate render layer with only glare nodes and brought that strip into sequencer and selected it as ‘Overdrop’.

You can use sequencer for single images, so it could have worked for you, but you shouldn’t have had to take this route. There is
something awry with the glare nodes, and I still assume it is me, until …

Definitely a rule of thumb is:

  • Plan to composite everything. “Fifty digital rolls of film on the floor … perfect.”
  • Every composite input channel needs to be “isolated” and “pristine.” (That can take some doing!) In other words, it needs to express only one thing, and it needs to express it without inter-dependence upon (or, garbage from) any other channel.

So, if e.g. you have a channel of “just the glare,” then you can of course mix that into the final, but you can also use it e.g. as a masking source, maybe after running it through a clipping highpass/lowpass filter of some kind. You can also do things like coloring the glare, doing it “here but not there” etc. Takes extra work but that’s how projects get done.