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Unsharp mask - new techncial article

Doug Kerr

Doug Kerr

Well-known member
The unsharp mask tool found in Photoshop and many other image editing applications is a powerful facility, and may here have great skill in using it.

Still, there is a fair amount of mystery regarding what really goes on "under the hood" with this tool, and even about why does it have that name.

I have just published on The Pumpkin a new technical article, The Unsharp Mask Process in Photographic Image Processing, available here:

http://dougkerr.net/Pumpkin/Index.htm#UnsharpMask

It describes the principles involved and the working of unsharp mask algorithms that are documented (or described in some detail in credible technical publications). It also discusses the term "unsharp mask" and what (if anything) it has to do with various forms of the process.

It is not a treatise on the effective use of the tool.

Best regards,

Doug

"Make everything as simple as possible, but no simpler"
 
Asher Kelman

Asher Kelman

OPF Owner/Editor-in-Chief
A nice start!

I'd consider a diagram of the mask A and/B n the film carrier exposing a piece of paper under the enlarger. Then, perhaps, use that same paradigm to deal with the edge math later on.

Asher
 
J

John Angulat

pro member
Hi Doug,
I just finished absorbing your latest effort. Very nicely done.
My best "take-away" was your explanations of radius and threshold, especially relating to gaussian blur.
Some many commercial publications (and goodness knows I've purchased a few!) barely offer any insight. Most left me scratching my head or wanting for more details.
A special thanks for the A-G graphs. I find it far easier to wrap my head around a graph rather than an image.
Thanks!
 
Asher Kelman

Asher Kelman

OPF Owner/Editor-in-Chief
Doug Kerr said:
Hi, Asher,


Thanks. Just something I did while waiting for my soup to get hot.

Do we know who will finish it?

Best regards,

Doug
Click to expand...

You often designate a version and I know from experience that you revisit your work with new layers of insight! So expect you will update it.

Asher
 
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