Looks like no one’s replied in a while. To start the conversation again, simply ask a new question.

A stain problem

Okay, I have a big problem with some of the stuff I shot the other day. I didn't clean the screen of my camera and I think there was particles on it because all my shirts turned out like the one below, with that brighter spot on the upper right of the screen (the bright spot on the hair)

User uploaded file
User uploaded file

Heres a closer look at it incase you didn't spot it.

User uploaded file


What is the best way to completely remove that annoying brighter spot?

Mac OS X (10.5.6)

Posted on Feb 15, 2009 1:30 PM

Reply
7 replies

Feb 15, 2009 1:41 PM in response to JosephTorres

The proper way to fix something like this is to use a defect map,
which is a matte that isolates the out-of-focus artifacts on the image.

The easiest way to generate the map is if you have some grey or white card footage,
so you can do a luma-key. If you don't have the reference card footage, you can
try frame-blending with the regular footage. The result should be a matte
that is mostly black, with a blurred grey area where the problem is.

Then you can use the defect map as a Travel Matte - Luma to do separate
color correction on that one spot. For best results, CC red, green, and blue
channels separately.

I know it sounds like a lot of work, but once you get it set up, it should work
for all the footage shot that day.

If you are able to do it, congratulations!
1. You've learned some really cool post-production techniques.
2. You'll never forget to clean your lens again.

Good luck!

Feb 15, 2009 3:09 PM in response to stuckfootage

Stuckfootage, you really are awesome!

But I hope you can deal with my newbie-ness just a little while longer.

I don't really know how to do all that stuff. Could you explain to me how to do each thing exactly?

How to use a defect map. What you mean by white card or grey card footage (as in actual footage of a white or grey card before doing a white balance?). How to frame-blend (the correct way anyways).

Please respond bro, thanks.

Feb 15, 2009 4:54 PM in response to JosephTorres

Look, I respect the fact that you want to learn and fix your mistakes,
but this might be pretty difficult to do. Reshooting might be a lot easier.

What you mean by white card or grey card footage
(as in actual footage of a white or grey card before doing a white balance?)


Yes, do you have it? Or at least an area where the blob is in a completely white
or grey area? Can you apply FCP's Key > LumaKey filter so that the blob is white
or grey and the surrounding area is black? If so, good, although you might need
to use a Matte > Four-Point Garbage Matte filter to make the whole frame black
except for the blob. Can you get that to work?

Feb 15, 2009 9:32 PM in response to JosephTorres

(as in actual footage of a white or grey card before doing a white balance?)

actually a frame or two AFTER you do the white balance....I assume that was just a typo.
Anyway, congratulations on pulling the lumakey and making a defect matte.

Now you have two clips, your original, and a still (defect matte) which is all black
except for a blurry grey blob right where the lens dirt was. Put that matte on your
timeline somewhere out of the way, make a copy of it, and apply
the Channel > Invert filter to the copy.

I assume that your original clip is in the timeline already on V1.
Shift-option-drag it up to V2, and release the option key before you release the mouse button.
Now you have two copies of the clip in perfect sync.

On the V1 clip, apply the Channel > Compound Arithmetic filter,
and set it to Multiply. See the little drop zone called Layer?
Drag the inverted defect matte into that box. You should see
a little image of the inverted matte in there.

On the V2 clip, apple the same Compound Arithmetic filter,
set it to multiply, and drag the (non-inverted) defect matte to its drop zone.

Set the Composite Mode of the V2 clip to Screen.
Now when you look at the doubled clips, they should
add together perfectly and it should look just like the original.
(There might be a little extra overall fuzziness if you need to render.)

Now try adding the Image Control > Brightness & Contrast filter
to the V2 layer. Try pulling down the brightness a little.
You should be able to see how it makes the blob a little less
noticeable. OK?

OK, now delete the Brightness & Contrast filter, and replace it
with the 3 way Color Corrector filter. Work with the levels
(the little sliders below each color wheel) and dial out the blob.
You can start with the mids, get them right, then tweak the
blacks to avoid having a ring.

Good luck!

A stain problem

Welcome to Apple Support Community
A forum where Apple customers help each other with their products. Get started with your Apple ID.