Artifacts when color-correcting...

Jaime Valles

Jaime Valles

Veteran
Hello, all! I'm working on a MiniDV feature shot with the DVX100 and edited on Final Cut Pro 4. Now I'm getting to the phase of color-correction, and I need your help.

When I do color correction on a clip with large areas of a uniform color, artifacts show up. Big, blocky, posterization artifacts. These do not appear on the original, unmodified footage, only when I change the colors to make it look really dark and cold. I understand that DV has limitations because of the severe compression inherent in the medium. But due to the nature of the scene (shooting day-for-night) I HAVE to do a lot of color correcting on it.

Is there any way to minimize the appearance of these artifacts? Any color-correcting techniques that I could apply to prevent them from showing up, or to at least diffuse them? I know some people here do color correction by up-rezzing the footage to "preserve color space"... Does this help with posterization artifacts? Would adding a grain-type filter be a solution, or would that just muddy up the final image?

I also posted this on DVinfo.net, to get as much input as possible. Any help would be greatly appreciated.
 
Re: Artifacts when color-correcting...

Make sure you're viewing output to a real video monitor, not the computer screen.

FCP has some color smoothing filters. Go through the list.
People have also had good results with filters from:
http://www.nattress.com/

Since you're going from bright (daytime) to dakr (night) you shouldn't be seeing too much artifacting; certainly not as much as the other way.
 
Re: Artifacts when color-correcting...

Well, I'm watching the footage on a 14" Sony NTSC pro monitor, so that's not the cause... Hmm...

I'll try the color smoothing filters, and see what happens and post back. Thanks for the reply.
 
Re: Artifacts when color-correcting...

[quote author=Scottdvx100 link=board=FCP;num=1094919701;start=0#1 date=09/11/04 at 10:49:32]Since you're going from bright (daytime) to dakr (night) you shouldn't be seeing too much artifacting; certainly not as much as the other way.[/quote]

That's exactly what I thought, but it's really severe. And it's not a Render Quality issue, I think. Everything is set to highest quality, and the unmodified footage looks perfect. Odd.
 
Re: Artifacts when color-correcting...

Step through what your color correction is. If you've pushed and pulled a lot of areas then you may be enhancign the grain.
 
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