Lenses and sharpening

nospam wrote:
In article , Floyd L. Davidson
wrote:

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.

But no matter how you try to squirm, no matter how you
squeal, *unsharp mask is a nonreversible function*.

For 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.

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.

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.

If it is actually measured, there will be an
insignificant difference.

I'm sorry that you have so much difficulty with
precision use of language.

In article , Floyd L. Davidson wrote:
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.

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_computing

Then read this,

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

And note the distinction between reversible and a
non-linear undo.

--
Floyd L. Davidson http://www.apaflo.com/
Ukpeagvik (Barrow, Alaska)

On Mon, 15 Sep 2014 10:15:37 -0700, Savageduck
wrote:

On 2014-09-15 16:39:45 +0000, (Floyd L. Davidson) said:

nospam wrote:
In article , Floyd L. Davidson
wrote:

UnSharpMask is not reversible.

it is with a non-destructive workflow.

I'm sorry that you don't understand the meaning of that.

I know your feelings regarding Photoshop, but using Adobe's *Smart
Object* concept provides a different level of non-destructive workflow.
Creating a new adjustment layer and converting it to a *Smart Object*
gives one the ability to apply any filter, including USM and any of the
other sharpening tools or filters to that *Smart Object*.
If the particular adjustment results are not to one's liking, then
double clicking on that filter in the *Smart Object* layer will reopen
the filter dialog to allow changes to the filter parameters.
In the case shown below I have applied USM to a *Smart Object* and I
can return to it as often as I want to adjust the USM parameters, all
non-destructively.
https://dl.dropbox.com/u/1295663/FileChute/screenshot_900.jpg

All adjustments made to *Smart Objects*, in Photoshop terms, are
non-destructive.

I fully expect you to tell me I am wrong.

I will tell you that you are discussing a point which is not the point
raised by Floyd. So too is nospam, but that is not surprising.

Floyd was referring to a reversible function: run it forwards and you
get sharpening; run it backwards and you get blur. Or the other way
around if you wish.
--

Regards,

Eric Stevens

On 2014-09-15 22:33:57 +0000, Eric Stevens said:

On Mon, 15 Sep 2014 10:15:37 -0700, Savageduck
wrote:

On 2014-09-15 16:39:45 +0000, (Floyd L. Davidson) said:

nospam wrote:
In article , Floyd L. Davidson
wrote:

UnSharpMask is not reversible.

it is with a non-destructive workflow.

I'm sorry that you don't understand the meaning of that.

I know your feelings regarding Photoshop, but using Adobe's *Smart
Object* concept provides a different level of non-destructive workflow.
Creating a new adjustment layer and converting it to a *Smart Object*
gives one the ability to apply any filter, including USM and any of the
other sharpening tools or filters to that *Smart Object*.
If the particular adjustment results are not to one's liking, then
double clicking on that filter in the *Smart Object* layer will reopen
the filter dialog to allow changes to the filter parameters.
In the case shown below I have applied USM to a *Smart Object* and I
can return to it as often as I want to adjust the USM parameters, all
non-destructively.
https://dl.dropbox.com/u/1295663/FileChute/screenshot_900.jpg

All adjustments made to *Smart Objects*, in Photoshop terms, are
non-destructive.

I fully expect you to tell me I am wrong.

I will tell you that you are discussing a point which is not the point
raised by Floyd. So too is nospam, but that is not surprising.

Floyd was referring to a reversible function: run it forwards and you
get sharpening; run it backwards and you get blur. Or the other way
around if you wish.

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.

…and if you have been following any of the PS books and tutorials, you
can get confirmation of what I wrote there with regard to *Smart
Objects* & resulting *Smart Filters*.

--
Regards,

Savageduck

In article , Eric Stevens
wrote:

All adjustments made to *Smart Objects*, in Photoshop terms, are
non-destructive.

I fully expect you to tell me I am wrong.

I will tell you that you are discussing a point which is not the point
raised by Floyd. So too is nospam, but that is not surprising.

Floyd was referring to a reversible function: run it forwards and you
get sharpening; run it backwards and you get blur. Or the other way
around if you wish.

there are indeed such functions, but that doesn't matter to users. they
want to edit photos, not learn mathematical theory.

when a user can modify an image and change it later, it's reversible
and that's why it's called a non-destructive workflow.

In article , Floyd L. Davidson
wrote:

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.

yes it is. it's one of the bests thing to happen to workflow.

It especially impresses
Chicken Little, Humpty Dumpty and nospam and probably
other cartoon characters.

resorting to insults means you're full of ****.

a non-destructive workflow is *much* more flexible, powerful and
productive than the old-fashioned way, which is why millions of
photographers practice it, including ones more famous than you.

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.

people use a non-destructive workflow so that any adjustment can be
reversed and/or modified after the fact.

you need to climb out of you narrow-minded thinking and look at what
the rest of the world actually does and why they do it.

For 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.

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.

look again:
Using one and then the other virtually reverses the results.


But the previous reference is in fact precise. The
reason for saying "virtually reverses"

so you admit you said it after all.

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.

there's no visible difference between a high quality jpeg and the
original either. in fact, the difference is barely there even under
close inspection.

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.

In article , Floyd L. Davidson
wrote:
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.

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.

i didn't say it was the same.

See: http://en.wikipedia.org/wiki/Reversible_computing

Then read this,

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

And note the distinction between reversible and a
non-linear undo.

non-destructive workflow is not non-linear undo.

you are once again talking out your butt and refusing to acknowledge
that you don't know something and that there are alternate ways of
doing things.

In article 2014091516100048753-savageduck1@REMOVESPAMmecom,
Savageduck wrote:

All adjustments made to *Smart Objects*, in Photoshop terms, are
non-destructive.

I fully expect you to tell me I am wrong.

I will tell you that you are discussing a point which is not the point
raised by Floyd. So too is nospam, but that is not surprising.

Floyd was referring to a reversible function: run it forwards and you
get sharpening; run it backwards and you get blur. Or the other way
around if you wish.

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.

what it boils down to is his definition of reversible is different than
what the rest of the world uses.

On Mon, 15 Sep 2014 16:10:00 -0700, Savageduck
wrote:

On 2014-09-15 22:33:57 +0000, Eric Stevens said:

On Mon, 15 Sep 2014 10:15:37 -0700, Savageduck
wrote:

On 2014-09-15 16:39:45 +0000, (Floyd L. Davidson) said:

nospam wrote:
In article , Floyd L. Davidson
wrote:

UnSharpMask is not reversible.

it is with a non-destructive workflow.

I'm sorry that you don't understand the meaning of that.

I know your feelings regarding Photoshop, but using Adobe's *Smart
Object* concept provides a different level of non-destructive workflow.
Creating a new adjustment layer and converting it to a *Smart Object*
gives one the ability to apply any filter, including USM and any of the
other sharpening tools or filters to that *Smart Object*.
If the particular adjustment results are not to one's liking, then
double clicking on that filter in the *Smart Object* layer will reopen
the filter dialog to allow changes to the filter parameters.
In the case shown below I have applied USM to a *Smart Object* and I
can return to it as often as I want to adjust the USM parameters, all
non-destructively.
https://dl.dropbox.com/u/1295663/FileChute/screenshot_900.jpg

All adjustments made to *Smart Objects*, in Photoshop terms, are
non-destructive.

I fully expect you to tell me I am wrong.

I will tell you that you are discussing a point which is not the point
raised by Floyd. So too is nospam, but that is not surprising.

Floyd was referring to a reversible function: run it forwards and you
get sharpening; run it backwards and you get blur. Or the other way
around if you wish.

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.

It's reversible only if you redefine the meaning of reversible in
Floyd's original statement.

…and if you have been following any of the PS books and tutorials, you
can get confirmation of what I wrote there with regard to *Smart
Objects* & resulting *Smart Filters*.

Well, yes. But that's not what Floyd is talking about. He could have
said isentropic, which would probably stop some of the bickering.
--

Regards,

Eric Stevens

On Mon, 15 Sep 2014 20:55:33 -0400, nospam
wrote:

In article 2014091516100048753-savageduck1@REMOVESPAMmecom,
Savageduck wrote:

All adjustments made to *Smart Objects*, in Photoshop terms, are
non-destructive.

I fully expect you to tell me I am wrong.

I will tell you that you are discussing a point which is not the point
raised by Floyd. So too is nospam, but that is not surprising.

Floyd was referring to a reversible function: run it forwards and you
get sharpening; run it backwards and you get blur. Or the other way
around if you wish.

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.

what it boils down to is his definition of reversible is different than
what the rest of the world uses.

Oh! - Hullo rest of the world!
--

Regards,

Eric Stevens

On Mon, 15 Sep 2014 20:55:29 -0400, nospam
wrote:

In article , Eric Stevens
wrote:

All adjustments made to *Smart Objects*, in Photoshop terms, are
non-destructive.

I fully expect you to tell me I am wrong.

I will tell you that you are discussing a point which is not the point
raised by Floyd. So too is nospam, but that is not surprising.

Floyd was referring to a reversible function: run it forwards and you
get sharpening; run it backwards and you get blur. Or the other way
around if you wish.

there are indeed such functions, but that doesn't matter to users. they
want to edit photos, not learn mathematical theory.

It mattered to Floyd and it mattered to me. The fact that it doesn't
matter to you is no ground for you reinterpet the meaning of
'reversible' and take over the conversation.

when a user can modify an image and change it later, it's reversible
and that's why it's called a non-destructive workflow.

Fine, fine. If you wear a reversible jacket do call it, too, a
non-destructive work flow?

Of course not. There are several subtly different meanings to the word
'reversible' and you seem to have only learned one of them.
--

Regards,

Eric Stevens

Savageduck wrote:
On 2014-09-15 22:33:57 +0000, Eric Stevens said:

On Mon, 15 Sep 2014 10:15:37 -0700, Savageduck
wrote:

On 2014-09-15 16:39:45 +0000, (Floyd L. Davidson) said:

nospam wrote:
In article , Floyd L. Davidson
wrote:

UnSharpMask is not reversible.
it is with a non-destructive workflow.
I'm sorry that you don't understand the meaning of
that.
I know your feelings regarding Photoshop, but using
Adobe's *Smart
Object* concept provides a different level of non-destructive workflow.
Creating a new adjustment layer and converting it to a *Smart Object*
gives one the ability to apply any filter, including USM and any of the
other sharpening tools or filters to that *Smart Object*.
If the particular adjustment results are not to one's liking, then
double clicking on that filter in the *Smart Object* layer will reopen
the filter dialog to allow changes to the filter parameters.
In the case shown below I have applied USM to a *Smart Object* and I
can return to it as often as I want to adjust the USM parameters, all
non-destructively.
https://dl.dropbox.com/u/1295663/FileChute/screenshot_900.jpg
All adjustments made to *Smart Objects*, in Photoshop
terms, are
non-destructive.
I fully expect you to tell me I am wrong.
I will tell you that you are discussing a point which
is not the point
raised by Floyd. So too is nospam, but that is not surprising.
Floyd was referring to a reversible function: run it
forwards and you
get sharpening; run it backwards and you get blur. Or the other way
around if you wish.

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.

That is in fact a valid statement. The USM function is
not reversible.

That isn't a opinion, it's a fact.

âEUR¦and if you have been following any of the PS books
and tutorials, you can get confirmation of what I wrote
there with regard to *Smart Objects* & resulting *Smart
Filters*.

--
Floyd L. Davidson http://www.apaflo.com/
Ukpeagvik (Barrow, Alaska)