Just what is a sharpening halo you ask?

[Jim Poor]

I've noticed some folks saying the don't see or know what a sharpening halo is. I have to admit, the first few times someone said my images had one I had no clue what they meant. Now most of the time I catch them, but still miss now and then.

Once you know what they are, they stand out like a sore thumb. So, I took an image and over did it and sharpened the whole thing a lot to introduce really obvious halos. Arrows show where they are.

Most of the time they are noticed in areas of high contrast like dark limbs, beaks, legs etc against a lighter BG like the sky. They can also be seen with dark BG and a light subject, but not as easily.

Selective sharpening is the best way to eliminate them. Select just your subject and be careful to select just "inside the lines" so as to not get any of the BG in the selection. To be sure, you can contract your selection using the Select > Modify > Contract menu.

[Alfred Forns]

Great idea Jim !!!! Never thought it might not be understood but you are correct !!!!

[Fabs Forns]

Excellent idea, Jim, thanks!!! :)

I have a tutorial on how to sharpen in sky or uniform backgrounds here:

http://birdphotographers.net/forums/...ead.php?t=6040

[Ian McHenry]

That's really good Jim.
I notice too that sometimes when noise reduced this also produces a halo.
If this happens I usually just accept the noise. LOL.
Any comments on this please.
Cheers: Ian Mc

[Jim Poor]

Not sure about noise reduction per se, but since it is basically a blurring effect I imagine careful selection is just as important. I know when blurring a BG one can get a bit of "zone" around the image that I wouldn't really call a halo. I've only recently started doing noise reduction the the NR filter. I've just been doing surface blur in most cases.

Shadow Highlight will produce a halo too, but it looks more like a glow than a bright distinct line most times.

[Fabs Forns]

That's really good Jim.
I notice too that sometimes when noise reduced this also produces a halo.
If this happens I usually just accept the noise. LOL.
Any comments on this please.
Cheers: Ian Mc

Ian, noise reduction should not give you a halo, unless you have the option to sharpen activated, which complicates things.

[Ian McHenry]

Thanks Jim and Fabs.
I'll check both points out next edits.
E.G.
Watch "Shadow Highlights" and noiseware settings ( no sharpen).

[Jim Poor]

Oh, I forgot to mention that for minor S&H adjustments, a radius of zero will avoid halos too. Anything more than minor needs to be done selectively though.

[Ian McHenry]

Thanks Jim.

[George DeCamp]

Nice job Jim!!!

[Gary Roberts]

Good information here. Thanks

Gary