Rick Hughes wrote:
The sharpening filter algorithm finds a contrast boundary and then darkens the one side and lightens the other.  Works fine but if you over-do the filter you end up with very obvious white edges called halos all over the place.  The way to sharpen without the halos - copy the image to a new layer - sharpen the image - and then set the layer mode to darken.  Halos disappear.  However, if the image already has halos this doesn't work.

An example is found in my photos.

The photoshop unsharp mask creates dark edge, not white. To remove halos, set the duplicate layer to lighten and not to darken. This is about unsharp mask PS. Are you talking about this?

Rick Hughes wrote:
The sharpening filter algorithm finds a contrast boundary and then darkens the one side and lightens the other.  Works fine but if you over-do the filter you end up with very obvious white edges called halos all over the place.  The way to sharpen without the halos - copy the image to a new layer - sharpen the image - and then set the layer mode to darken.  Halos disappear.  However, if the image already has halos this doesn't work.

An example is found in my photos.

fireshoot wrote:

The photoshop unsharp mask creates dark edge, not white. To remove halos, set the duplicate layer to lighten and not to darken. This is about unsharp mask PS. Are you talking about this?

It's more of a hack and not a technique. There is a way to do it but for some reason it's still not implemented in photoshop as a simple slider.
The idea is to NOT sharpen edges that are already sharp by masking them out using edge detect filter.

Or...use another method of extracting details from the image instead of Gaussian Blur (which is used in both Unsharp Mask and High Pass filters). Median for example.

Andrey Bautin wrote:
It's more of a hack and not a technique. There is a way to do it but for some reason it's still not implemented in photoshop as a simple slider.
The idea is to NOT sharpen edges that are already sharp by masking them out using edge detect filter.

Or...use another method of extracting details from the image instead of Gaussian Blur (which is used in both Unsharp Mask and High Pass filters). Median for example.

Yes. I use a different technique about unsharp mask. Can see it in this my old video tutorial. That video is one way. Good sharpness needs 3 steps.Capture sharpen, Artistic Sharpen, final sharpen for printing.
The video show is the second of this.
https://www.youtube.com/watch?v=2zZzKla7hGo