Purple fringe removal?

[mark_hay]

Is there any additional feature or help to remove purple fringes from high contrast edge areas please in PWP 7?
(I was just looking for a convenient way to do this - and have seen Den's methods previously.
Looks like Helicon Filter has an approach that would be nice to see in PWP.)
Thanks, Mark.

[jsachs]

No plans for this release, but I will take a look at it again.

[jsachs]

I am playing with some ideas for purple fringe removal - if anyone has sample images that illustrate this they are willing to contribute, please email them to me at jsachs@dl-c.com

Thanks

[den]

Jonathan...

I have observed that 'lateral' chromatic aberration seems to be best reduced in the Raw conversion before gamma, color profile, expansion, and sharpening occur.

At the very least, before any post conversion sharpening is performed as sharpening will make the chromatic aberration harder to reduce.

Of course, I am lumping 'Purple Fringing' with chromatic aberration.

Please see this thread on the SNS-HDR message board for an example/illustration: http://www.sns-hdr.com/forum/viewtopic.php?f=7&t=353 that shows significant reduced chromatic aberration when performed during raw conversion before any post-conversion edits.

I have the illustrated image file available that has significant chromatic aberration. Are you interested in a RAW file (CR2)? ...or a 100% jpeg quality, full sized 3456x2304 of a PWP7 RAW Dialog conversion-edits output tiff?

...den...

[jsachs]

I am coming to believe that purple fringing is caused by a clipped pixels spilling over into the blue and red channels of adjacent pixels - most of the examples I have seen have none of the qualities of CA as the purple always seems to be next to blown highlights and does not exhibit circular symmetry and CA is not just one color. Some of the worst examples I have seen from the web were around specular highlights. Another common case is tree branches or buildings against a bright sky.

Anyway I don't need a huge image - a jpeg or tiff is fine.

[mark_hay]

Hi Jonathan - I have emailed you some examples,
thanks, Mark.

[mark_hay]

I have found the Purple Fringe Removal works very well on Jpegs. I saw problems with TIFFs causing PWP to stop but I understand that is a Beta test issue and will be fixed.
I really like the controls including the ability to apply a mask; and this transformation is available also in the PWP workflow. Will be very useful!

[jsachs]

I am not aware of any problems with Defringe that cause PWP to crash. If you have any files that cause this, please email them to me when you get a chance (jsachs@dl-c.com).

[mark_hay]

Hi Jonathan - I will email you the TIF now.
Problem occurs as follows:
1. I open the image TIF file (3888 x 2592 pixels) in PWP 7.0.6 Beta (size about 60MB)
2. I apply the transformation Color - Defringe having set parameters to:
Purple color range
Amount 100%
Radius 3
Threshold 50%
(no mask used)
3. Preview is updated showing defringe has worked.
4. I click OK
5. After about 10 seconds I get the error
After a few seconds its says PWP has encountered and error and needs to close.
(My PC is an HP Pavilion AMD Athlon 3700+ 2.19GHz with 3GB Ram... Windows XP Home Edition SP3.)
thanks, Mark

[mark_hay]

I have just done one quick test and the latest beta release has fixed the problem I encountered when using the Defringe on 48 bit images. Thanks to Jonathan and team!