Getting white edge while compositing

Was wondering if someone can take a look at this, at the moment I’m trying to get to grips with composting but was wondering if there was any way of improving this image that I have below.

You might be able to notice a light outline around the cube after compositing is there any way of removing (stopping it appearing in the first place ). Here is the node structure not sure it anyone needs the blend file



Try clicking ConvertPremul in your AlphaOver node.

Covert premul should work. But to be safe for all cases as in images with sky I would turn the sky button off for all layers except the background.

I’m not sure if this is what we’re dealing with here, but I do know that you have to be very careful when dealing with objects that are rendered with their own lighting-artifacts: shiny edges, casting shadows, or what have you. Depending on how you algorithmically combine the layers, and how you mask them, you can “add-up light” in places such that it all looks wrong and it just doesn’t work. For example, I’ve made mistakes where two objects are passing one in front of the other, and highlights from the rear object can be seen as though they were passing over, or through, the front object. The alpha-information was being combined incorrectly.

You might find that you need to composite neutrally-lit objects, then add the highlighting and the shadows as a separate “beauty pass.” You can control the types of information that contribute to a masking channel, and you might need to omit things like specularity from that.

Cheers guys for the suggestion as I thought I was setting some thing or other

even with the suggestion I can get rid of that other line , It looks like some kind of edging through back

changing the Covert premul just darkens the color to a blackish tint

I guessing that the sky butting is under the render layer pass but i could be wrong as it doesn’t have any effect

any other suggestions


Just had another look at your node setup - you need to connect the alpha from RenderLayer 2 to your AlphaOver node. Then you will either need to enable ConvertPremul (or do as Cyborg Dragon suggests and enable Premul in the Scene options).

I was answering another post when I accidentally came across what may be the solution to your problem. It appears that you may have “sky” enabled in your render settings, either in the renderlayers pallet or in the render pallet (F10 key for both pallets). Disabling this in both pallets completely ommitted the blue halo that you will see in my post here:
The blue halo that surrounds the spheres is much more apparent than can be seen in the post, heavy jpg compression for bandwidth purposes did away with a lot of it. Even with premultiply enabled the halo was still apparent just not as much so.