-
Correcting chromatic aberrations (purple fringing)
I was using my HDV camera at the full focal length of the lens on some high contrast/brightness shots and have got some noticeable purple fringing. To be expected of course.
Just had a look around for advice on this. Found plenty of tips for creating this effect using channel offsets but not much on how to correct it.
I was wondering whether anyone had any neat tips in FCP, Color, AE, Shake or maybe even using the film strip mode of Photoshop to remove this neatly?
-
2 Replies
-
[Paul Ramsbottom] “I was using my HDV camera at the full focal length of the lens on some high contrast/brightness shots and have got some noticeable purple fringing”
This sounds like trouble to me. I can think of some techniques that might possibly reduce the fringing, but probably won’t eliminate it entirely.
One technique you could try would be separating the RGB channels into layers and applying a Channels > Minimax effect to the blue & red channels. Use the minimum function with a radius of 1 pixel and see what happens… You may also need to very slightly blur the result. This may not work very well.
Another would be to use an edge matte generated from the luma values of the footage to matte a Curves effect with settings to correct the color as best you can. Try a Channels > Channel Combiner effect to go from RGB > YUV then Channels > Shift Channels to shift the R,G and B channels to the ‘Red’ (now the ‘Y’ or luma channel) channel and then apply Stylize > Find Edges. You may need to invert that and blur it some to generate a good luma matte for your Color Correction > Curves effect.
I haven’t tried either of these, just some things that I thought of on the spot, let me know if there are problems with either one and I’ll try to come up with a solution.
Darby Edelen
Designer
Left Coast Digital
Santa Cruz, CA -
Not sure if your still having problems with this?
I’ve found away to correct chromatic abberation, it seems ridiculously simple – but it seems to work like a dream for me at least.
In FCP just go into video filters, ‘channel offset’ and pick the blue channel. Move it to by -1.5 or 2 in the left box and (depending on how bad the fringing is) it should fix it.
I spent HOURS trying all sorts of thing including a couple of plug ins and this has fixed it the best hands down.
you may need to do a couple of layers and matting if its really bad as the offsetting can correct the abberation in some places (say the far left of the screen) and create it in others (on the far right of the screen).
Hope this makes sense, its my first post and just wanted to pass on what I found out at 3am while struggling on a project!
Reply to this Discussion! Login or Sign Up