COLOR FRINGING

[Edmond Junker]

Hi folks,,,,I know this topic has already been discussed but at that time i was not concerned and now i have lost the connection......my fault!
If i want to sharpen(slighly) lets say the horizontal edge of a roof(tyles,,,shingles) and i have a very blue sky,the outcome will be a white fringe along the edge.This is particularly annoying as one cannot see it till
the picture is enlarged(i.e printing).The same is true if there is a darker object reaching into a lighter one(trees into a lighter sky).Photoshop cannot do much about it and the picture is most of the time rejected.
Can someone cleverer than i am lighten me up.

[Geraldo Garcia]

Looks like you are talking about sharpening halos instead of color fringing.
Sharpening procedures usually try to improve acutance of the edges by creating a halo that darkens the dark side and lightens the bright side. Some methods may give you more control about that (like smart sharpen in photoshop) but the truth is: if you want a halo free image you have to spend some time over it. On some cases people go over the sharpened image and erase/clone out the white halo manually, but that surely negates part of the perceived acutance. The pseudo RIP Qimage claims to have an improved sharpening algorithm called Deep Focus Sharpening that is supposed to be almost halo-free. It may be worth a look.

[mcbroomf]

There are many ways to sharpen and many programs to use.  There should be a way to get halo free images unless you are asking too much for the image in question. 
I suggest you give more details; the source of the file (ie camera, raw, jpeg), programs you're using and what settings.  Posting examples of before and after your sharpening may be useful.

[louoates]

A similar situation may be caused by adjustments in Camera Raw sliders. For example, in Raw, by sliding the Blue channel luminosity adjustment to the left it will darken the blue sky but will cause some white fringing where the blue abuts other colors. You should be able to see any problems like this at 100% in PS. I love those color adjustments in Raw and have simply fixed the fringes by cloning along those lines that offend.

[Ernst Dinkla]

As mentioned Qimage Ultimate does it well and there are more sharpeners like deconvolution types that will not create halos right away. However any artefacts already in the original file will be exaggerated by any sharpening tool, compressed JPEGs are a good example. Sharpening building on color fringing another.



--
Met vriendelijke groet, Ernst

http://www.pigment-print.com/spectralplots/spectrumviz_1.htm
April 2014, 600+ inkjet media white spectral plots.  

[Edmond Junker]

To all of you who kindly answered my request!
I shall apply all possible methods given to me by each of you and thanks to everyone.So long folks.