Earth explosion

I am putting together an earth-explosion and have rendered it out as a mov. file using rgba and premul settings. After i place the explosion on a white background i get these gray areas outside the halos and the explosion. how can i remove this gray color? thanks to [email protected] for material by the way.
see mov. file here:


What program are you using to composite the white background?

For this example it might be easier to just set your world color to a solid white.

thanks for reply. i am using final cut pro. the problem is; i want to be able to control the globe as an independent object so i am able to put things behind the explosion as well. it just gives more freedom when making stuff…
must be some other solution on the alpha channel setting or something?

Theres a reason for everything with blender, you may want to look at the alpha channel by plugging a viewer node to the alpha channel out on the render layers node in the compositor.

I really don’t know of any obvious problems that could cause your situation, but if nothing looks strange on the alpha channel in the compositor, upload your .blend and let me look at it.

i didnt find anything… but i am not that skilled yet as well…
here is the blend nbninja8.
thank you.

Okay, I’m pretty sure that it is a problem with the Quicktime codec you are using. I exported a frame as .tga and it looked just fine.

Try exporting this to a .tga or .png image sequence and import that into Final Cut. Final Cut can import image sequences right? Final Cut is such a strict program when it comes to anything other than quicktime.

Just curious, why do you want to do your compositing in Final Cut and not in Blender’s Compositor?

Also, nice job on your materials, I’m seriously going to have to study your .blend to figure out how you did some of those things!

hey. thanks. well as i said; credits goes to [email protected] and blender freepository. but i am glad you liked it. i try it with png. or tga. like you said. i am using fcp i am mixing film and animations. i never managed blender to handle video very well. jagged edges. so i use fcp because it is my main video editor.
thanks. i will try ur suggestions…

well, i tried your suggestion. The files are coming out as undefined documents and not png picture files. Is this right? in that case fcp doesn´t even recognize the files…
i tried with jpg as well, but the pictures does not show up as jpg in my finder. even photoshop cant open them…
am i overseeing something?

okay, have a look at these screencaptures: Here is the result of combining the image over a white background in the compositor with and without the pre-mulitplication checked on the alpha over node.

I’m not an expert and this subject really confuses me, but this is where the problem is.

This problem will be the same regardless of the format, quicktime, tga or png.

So in order to display the image properly in Final Cut you would have to change the alpha type, you can do this in Final Cut and this link shows you how:

Scroll down to where it says Changing a Clip’s Alpha Channel Type
After following the instructions, set the alpha channel to black.

This is new information to me, I don’t usually export files with alpha channels. But apparently there are different types of pre-multiplied alpha channels. Looks like I’m going to have to do some research on that.

That should do the trick.

I don’t know why blender exports the image with no file extension, but you could always add an extension, (.tga) and then it should open in any image program.

When you are preparing files for use in compositing, I suggest that you use the MultiLayer (OpenEXR) file formats, which are specifically designed to be digital-input files (not displayable images). They keep all of the channels of information, separately, and with a high degree of numeric precision. (They might be large, but who cares? Hard drives these days are larger.)

Do the entire process using those formats, up-to and including the final print master. Then, reprocess that final master to generate whatever “displayable” format(s) you need, always working directly from the master each time. You don’t want to compress, don’t want to throw away any information, except in that last step. (And since the master from which you are working contains all that data, of course you haven’t actually “thrown away” anything at all.)

the alpha channel thing did the the trick yes. I didnt know this, and it will help me when making other animations too. thanks so much for taking a serious look into it.
You learn every day:) i will check out the exr too.

add a blur node :smiley: