Subject | Re: Lenses and sharpening |
From | nospam |
Date | 09/16/2014 02:55 (09/15/2014 20:55) |
Message-ID | <150920142055311939%nospam@nospam.invalid> |
Client | |
Newsgroups | rec.photo.digital |
Follows | Floyd L. Davidson |
Followups | PeterN (14h & 41m) |
yes it is. it's one of the bests thing to happen to workflow.Floyd L. DavidsonnospamFloyd L. DavidsonnospamFloyd L. DavidsonFloyd L. Davidsonnospam
UnSharpMask is not reversible.
it is with a non-destructive workflow.
I'm sorry that you don't understand the meaning of that.
i absolutely do know the meaning, since it's all i use.
it's you who doesn't understand what a non-destructive workflow means
A non-destructive workflow means you can *undo* and then *redo*.
That is not a reversible function.
it is to the user, which is what matters.
in other words, the user sharpens today and then tomorrow or next month or whenever, they can readjust it or remove it entirely. that means to the user, it's reversible.
that's why a non-destructive workflow is so powerful.
Non-destructive is wonderful.
It especially impresses Chicken Little, Humpty Dumpty and nospam and probably other cartoon characters.resorting to insults means you're full of shit.
But no matter how you try to squirm, no matter how you squeal, *unsharp mask is a nonreversible function*.the function is not used standalone so that doesn't matter.
look again:Floyd L. DavidsonFor example, you can add sharpening with a high pass sharpen tool to an image, save it as a JPEG, send it to someone else, and they can use a blur tool to reverse the sharpen.nospam
not perfectly. you even said 'virtually reverses' in your description.
that's another way of saying 'there is some loss.'
I don't see the term "virtually reverses" in that sentence.
nospam
Using one and then the other virtually reverses the results.
Floyd L. Davidsonso you admit you said it after all.
But the previous reference is in fact precise. The reason for saying "virtually reverses"
is because if the sharpen and blur algorithms are not exactly the same and using precisely the correct parameters, the reversal isn't total. Which is to say that if it is done by inspection the result will be such that there is no visible difference.no visible difference is another way of saying there's a difference, but you just can't see it.
If it is actually measured, there will be an insignificant difference.so there is a difference, just as i said.
I'm sorry that you have so much difficulty with precision use of language.i'm not the one with the difficulties.
i didn't say it was the same.Floyd L. DavidsonIn article <87bnqh1mby.fld@barrow.com>, Floyd L. Davidson <floyd@apaflo.com>wrote:nospam
Not the case. It is the high pass sharpen tool that is the inverse of blur. They can use the exact same algorithm with different parameters. Using one and then the other virtually reverses the results.Floyd L. Davidsonnospam
If the sharpening is done with UnsharpMask that cannot be done. USM is not reversible.
in a destructive workflow that is true.
in a non-destructive workflow, it is not true.
Obviously you didn't understand what the term "reversible" means, and thought non-destructive is the same. It isn't.
See: http://en.wikipedia.org/wiki/Reversible_computingnon-destructive workflow is not non-linear undo.
Then read this,
http://en.wikipedia.org/wiki/Undo
And note the distinction between reversible and a non-linear undo.