get rid of static grain in post? at DVinfo.net

Leonard Levy · March 14th, 2009, 03:26 PM

I have static grain in an interview shot of a guy against the sky.
Classic problem I know I should have known better but I didn't see it even in my 8" panasonic monitor.

Any ideas for how to fix it in post on a Mac?

Shot in HDV on a canon. I have Final Cut Studio 6.04 and an old version of after affects that I've never learned to sue.

I have tried to mask off the sky using a secondary color correction for a key and then applied a gaussian blur to that. It helps but I'd like to do better. I don't want to blur out the subject as that's already too soft.

I'd love to get rid of it all over the image, but if I can fix only the sky it would be a big improvement. Fortunately in the shot the whole background is far away so it is all much softer than the subject.

Lenny Levy

Bob Hart · March 14th, 2009, 07:46 PM

There was a method posted here way in history back which described dealing with an edge/corner brightness brightness falloff problem but it is unlikely to help you here.

It relied on the defects in the image remaining constant in the frame and required the shooting of a mask against a plain background to be applied against the original image in a separate layer.

Unfortunately, it may be beyond you to shoot that mask as your groundglass will surely have moved by now.

In theory you could try, as the groundglass texture detail itself will not have changed unless you have cleaned or dismantled it. Only its horizontal and vertical position will have if the camera/adaptor alignments have not otherwise been disturbed.

However, this does not account for the zoom and relay focus positions which will be impossible to reproduce precisely. Only a fixed relay lens system would offer any chances.

Assuming you were able to create this mask. you would need to be able to move it about on top of the original image to get the individidual "grains" in each image to co-incide. The edit system may not permit you this degree of precision.

Chances are, you will have a problem of angular misalignment, especially if you have dismantled the adaptor from your camera. If you have done this, that is likely your lot.

Hopefully others who know more can enlighten you on the method.

You may be able to create a partial mask from your original footage to deal with the sky by pulling the colour out, making the image a negative, then playing around with the brightness and contrast levels on the masking layer. It might be easier to simply shoot a new background plate of perfect sky and apply that.

March 14th, 2009, 03:26 PM	#1
Leonard Levy Trustee Join Date: Feb 2006 Location: USA Posts: 1,684	get rid of static grain in post? I have static grain in an interview shot of a guy against the sky. Classic problem I know I should have known better but I didn't see it even in my 8" panasonic monitor. Any ideas for how to fix it in post on a Mac? Shot in HDV on a canon. I have Final Cut Studio 6.04 and an old version of after affects that I've never learned to sue. I have tried to mask off the sky using a secondary color correction for a key and then applied a gaussian blur to that. It helps but I'd like to do better. I don't want to blur out the subject as that's already too soft. I'd love to get rid of it all over the image, but if I can fix only the sky it would be a big improvement. Fortunately in the shot the whole background is far away so it is all much softer than the subject. Lenny Levy

March 14th, 2009, 07:46 PM	#2
Bob Hart Inner Circle Join Date: Dec 2003 Location: PERTH. W.A. AUSTRALIA. Posts: 4,477	There was a method posted here way in history back which described dealing with an edge/corner brightness brightness falloff problem but it is unlikely to help you here. It relied on the defects in the image remaining constant in the frame and required the shooting of a mask against a plain background to be applied against the original image in a separate layer. Unfortunately, it may be beyond you to shoot that mask as your groundglass will surely have moved by now. In theory you could try, as the groundglass texture detail itself will not have changed unless you have cleaned or dismantled it. Only its horizontal and vertical position will have if the camera/adaptor alignments have not otherwise been disturbed. However, this does not account for the zoom and relay focus positions which will be impossible to reproduce precisely. Only a fixed relay lens system would offer any chances. Assuming you were able to create this mask. you would need to be able to move it about on top of the original image to get the individidual "grains" in each image to co-incide. The edit system may not permit you this degree of precision. Chances are, you will have a problem of angular misalignment, especially if you have dismantled the adaptor from your camera. If you have done this, that is likely your lot. Hopefully others who know more can enlighten you on the method. You may be able to create a partial mask from your original footage to deal with the sky by pulling the colour out, making the image a negative, then playing around with the brightness and contrast levels on the masking layer. It might be easier to simply shoot a new background plate of perfect sky and apply that.