On 14/09/2014 08:30, Alfred Molon wrote:
In article 2014091316132932858-savageduck1@REMOVESPAMmecom, Savageduck
says...
...and what PP software, & what sharpening methods do you use?
I am not going to advocate one application, or method over the other, I
know what advice I can give with what I am familiar with in my workflow.


Isn't unsharp mask the same across all PP applications? I would have
thought it's an algorithm which is implemented in various PP
applications, or are there differences?

Unsharp mask historically was implemented by physical means to allow
very high contrast images to be more satisfactorily be represented on
printed media. It got adopted by David Mailn of the AAT to bring out
faint low contrast details in nebulae that would otherwise be invisible.

http://en.wikipedia.org/wiki/David_Malin

And from there it entered mainstream digital image processing.

It was in use for advertising purposes for quite a while prior to that.

The details of most algorithms are roughly similar but how they handle
underflow and overflow of pixel values may vary with implementation.

--
Regards,
Martin Brown