Controlling white halos in USM

[tomczak]

The more methods of sharpening I try, the more I like USM. If not overdone, the images look mostly natural, except for halos, which are really easy to create. One effective method of dealing with halos is to suppress the light portion of them, which is more obnoxious than the darkened portion of edges. While it can be easily done manually (e.g. USM --> composite(base image=input; overlay=USM-sharpened; Operation=darken), it's hard to do it in a workflow. Is there a way of automating it, or perhaps adding such option to USM?

Cheers.

[MikeG]

No idea how to automate - but, Thanks for a great tip!
Mike.

[den]

(e.g. USM --> composite(base image=input; overlay=USM-sharpened; Operation=darken)

Rather than use two sequential transforms, [USM and Composite-Darken], perhaps just use the USM transform with an 'active' Invert-ed HSV-V tone-map mask where the USM Input mask white = 0 and mask black = 100. This would also give one control to add the white half of the sharpening as well if preferred. I usually like white to be 1/3 of the black amount....

(1) click or open an image;
(2) open the Mask Tool - BrightnessCurve; lower-left Apply Add the default diagonal curve: [0,0], [100,100]; and leave 'active';
(3) click on the image and open the Sharpen-USM transform setting mask white = 0 and mask black = 100 or preference with other preference USM settings. [as suggested perhaps mask white could be changed from 0 to 33.3 without objectionable white halos].

Another way that the above could be done is with two workflows: (1) one to create the masks using the ColorCurves widget where HSV-S and HSV-H curves are set to [0,0], [100,0] plus a Convert widget to 8-bit B/W; and (2) one with the Sharpen widget set to USM preference settings and interrupted to make starting and mask image changes with the mask images open in PWP's working space; and three temporary folders: (1) the starting images; (2) the mask images; and (3) the final destination folder.

However, the effort here to run the second workflow with the appropriate starting image and its associated mask is rather daunting!... but then I am not a wfl wizard... and perhaps the two wfl's could be linked as well.

[den]

Slightly OT...

...The foregoing approach to control white halos when sharpening seems to work well with other sharpening methods [Bilateral Sharpen, Advanced Sharpen, Sharpen, Heavy Sharpen, and HighPass-Soft/Hardlight Blending] and/or when performing 'local contrast enhancment' with these methods... ...Ask if any need more detail...