View Full Version : black renders in render

11-10-2008, 08:08 PM
Hi guys. Anyone had problems with renders in lw that have some black outlines around objects? I can't get rid of them even if it has alpha channel. It seems to happen when I use hdr backdrop.
Here's a sample render. I have to use matte choker in AE all the time and its a pain.

Andrew March
11-11-2008, 03:10 AM
Upload a jpeg to here please.

11-11-2008, 04:16 AM
Upload a jpeg to here please.

The zip file has a tga with alpha. When imported it to photoshop or AE there's some kind of black line around the object. Its very very thin but noticeable when you zoom in.

CC Rider
11-11-2008, 06:58 AM
I just imported into AE and it looked great to me...no black lines visible.
Here is a screen shot of what I saw.

CC Rider
11-11-2008, 07:12 AM
You are correct that you can see a very faint outline that disappears when you apply the "Remove Color Matting" effect, but it is barely noticable...unless you zoom in past 100% which really isn't a fair test.

But it is there and enough to cause problems for you obviously.
I pretty much always use the remove color matting effect to get the cleanest possible composite. Or import the footage using the "Premultiplied" setting. Usually achieves the same thing...


Richard Hebert
11-11-2008, 07:26 PM
I sometimes have this problem and use a matte choker as well. Using pre-mult. works as long as it isn't a 'glass' surface, a cockpit canopy for example. With glass, the transparent areas tend to darken using the pre-mult. I'm using a much older version of AE (AE 5.5) so I'm not really sure if this could be my culprit. Judging from what you've written though, it probably isn't. Has anybody else had any compositing issues with transparent areas in AE?


11-11-2008, 09:35 PM
I get that and just run a batch process to remove black matte

11-11-2008, 09:38 PM
Believe me in japan they are very anal about this stuff. Even that very very faint line will not pass my TD. I dont know why lw is outputting this.

11-11-2008, 09:55 PM
I see the black line.

LW has a premult setting in the Output tab of the Render Globals panel, try changing that perhaps?

11-11-2008, 09:57 PM
Render Globals panel, I ticked off render lines all the time. What else in there should I turn off?

Btw lw forum is giving me virus alert.

11-11-2008, 10:20 PM
In Render Globals on the Output tab is an Alpha Format option. Try rendering with both options and see which one comes out correctly for you.

CC Rider
11-12-2008, 08:08 AM
If you are using AE, using "Remove color matting" effect will get rid of it completely.
I use it all the time, works like a champ.