Subject | Re: Lenses and sharpening |
From | Savageduck |
Date | 09/16/2014 11:08 (09/16/2014 02:08) |
Message-ID | <2014091602083419009-savageduck1@REMOVESPAMmecom> |
Client | |
Newsgroups | rec.photo.digital |
Follows | Martin Brown |
Followups | Floyd L. Davidson (1h & 27m) > Savageduck |
Martin BrownExactly.
On 16/09/2014 05:37, John McWilliams wrote:John McWilliamsMartin Brown
On 9/15/14 PDT, 7:07 PM, Floyd L. Davidson wrote:Floyd L. Davidson
Savageduck <savageduck1@{REMOVESPAM}me.com>wrote:Savageduck
I got what Floyd was talking about when he was talking of high pass sharpening, and reversing it by applying the corresponding reverse parameter blur. However, he also stated above, "UnSharpMask is not reversible". My point addressed the fact that for some of us, that is not an entirely valid statement.
IN an environment that supports a saved original copy so that all edits are non-destructive then that is true.
But the mathematics of blurring and of unsharp masking make it irreversible if you are only given just the processed image. (and not some hybrid Photoshop workflow encapsulated format)So? The fact still remains, regardless of personal opinion about Adobe, Lightroom, & Photoshop, those using that software have the ability to maintain a fully non-destructive, and reversible workflow, that includes reversing the effects of any filter including USM.
Normal imaging processing? You might have noticed that currently, Adobe produces the industry standard software in that category, and those of us who use Lightroom and Photoshop have been provided the tools to maintain a truly non-destructive and reversible workflow.Martin BrownFloyd L. DavidsonJohn McWilliams
That is in fact a valid statement. The USM function is not reversible.
That isn't a opinion, it's a fact.
For one definition of the word!
This seems to have degenerated into a heated and utterly pointless semantic argument over the meaning of "reversible" that is in conflict with normal image processing and mathematical parlance.
A mathematical operation is reversible if a strict inverse function exists that can exactly get you back to where you started.…and if you are going to start that reverse mathematical operation from a compressed, & lossy JPEG, good luck getting back to where you started.
Any operation can be made non-destructive simply by saving a copy of the original before applying the irreversible filter but that isn't very interesting.However, that isn’t quite how things work in a truly non-destructive workflow. What you have described is what at best could be called a pseudo-non-destructive workflow. Just working on a duplicate of the original isn’t the idea. To be truly non-destructive and reversible one has to be able to return to the actual file they were working on. That is going to be either a layered PSD, or TIF. The JPEG which might be produced is just a compressed, lossy snapshot of the actual, non-destructively adjusted, and uncompressed layered PSD, or TIF. It is best to consider it a version, and there is no point in even trying to rework it. Call it “version-1.jpgâ€. Once you are done with readjusting the layered PSD/TIF you can produce “version-2.jpgâ€, and still have the ability to return to the working PSD/TIF to produce a “version-3.jpgâ€.
Some packages do support this sort of safe workflow.I know, I know.