Lenses and sharpening

In article , Eric Stevens wrote:

As I said, that genius Floyd did.

Yes, I found that text, but I don't think that it means what you
seem to think it means. He wasn't claiming that JPEG is fully
reversible: everybody knows that it isn't.

He did make this claim:

Floyd L. Davidson
Lenses and sharpening
09/15/2014

"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."

That is an *incorrect* statement. When you have added JPG compression to
the file, the "someone else" *can not* reverse the HPS effect with Gaussian
Blur. The end result may be *similar* to the original image, but the effect
will *not* have been reversed.

Floyd is very very ignorant about these things. You really should stop
playing in his corner.

Based on what Floyd has been saying all along, the obvious series of
processes would be:

1. Sharpen image.

2. Save file as TIFF

JPG you mean. That is what he said.

3. Apply Gaussian blur to TIFF image to recover original image
sharpness.

Applying GB to the JPG will *not* reverse the HPS, contrary to this
incorrect claim.

This series of processes is possible if you sharpen with a high pass
filter but not possible if you sharpen with unsharp mask. i.e. the
original image is recoverable if you sharpen with the high pass
filter.

Not using Floyd's method, no.

Floyd then went further and, as you quoted, proposed an alternative
series of processes:

1. Sharpen image.

2. Save file as JPEG

3. Apply Gaussian blur to JPEG image to recover original image
sharpness.

This is the only method Floyd has suggested. He never talked about TIFF's.

... and claimed that, again, this process also is possible if you
sharpen with a high pass filter but not possible if you sharpen with
unsharp mask. i.e. the original image is recoverable if you sharpen
with the high pass filter.

I.e. he made an incorrect claim, he doesn't know what "reversible" means
and has no idea that JPG adds compression. No surprise there.

I understood him to be saying that inspite of the losses of a JPEG
conversion, recovery of the original sharpness is possible if the
original sharpening process used a high pass filter.

It may look similar, but the effect is *not* reversed. At most, it is
counteracted.

That while saving as a JPEG will always cause losses, this will not
prevent a Gaussian blur operation from recovering the sharpness of the
original image.

Indeed it will.


--
Sandman[.net]

In article , Eric Stevens wrote:

Savageduck:
If you make the adjustments in Photoshop with a
non-destructive workflow there is no use of sidecar files or
catalog entries as in Lightroom.

Eric Stevens:
True, but this has nothing to do with whether a process is
reversible or not.

nospam:
if it can be reversed, then it's reversible.

since you finally agree that adjustments made in photoshop can be
reversed, then it's reversible.

I don't know of any operations in Photoshop which are reversible in
the strict sense that Floyd was using the term.

All of them are reversible, in every sense of the term.

Some aaspects of smart objects might be, but I don't know enough about
them yet to venture an opinion.

We know you don't. That's why we are educating you guys about what can be
done with modern software.


--
Sandman[.net]

In article , Floyd L. Davidson wrote:

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.

If the sharpening is done with UnsharpMask that cannot be done.
USM is not reversible.âEUR�

And that is true!

100% false.

Eric Stevens:
I understood him to be saying that inspite of the losses of
a JPEG conversion, recovery of the original sharpness is
possible if the original sharpening process used a high pass
filter. That while saving as a JPEG will always cause
losses, this will not prevent a Gaussian blur operation from
recovering the sharpness of the original image.

Floyd L. Davidson:
Again, that is extremely close but lets not suggest that the
"sharpness of the original image" is *fully* recovered. In
other words "sharpness of the original image" is not the same as
"original sharpness".

Savageduck:
So, it isnâEUR(Tm)t a fully reversible and/or non-destructive
process?

I've never claimed it was in any way a "non-destructive process".

Reversible does not necessarily mean revertable from one specific
state to another specific previous state. It means incremental
variation is incrementally reversed. How far it can be taken is
another matter.

We already know you have no idea what "reversible" means, Floyd. No need to
remind us with *every* post. The scenario you described is not of something
that has been reversed. You failed, and you know it. That's why you're
dancing around like a scared little boy right now unable to add any more
actual arguments to the thread.

Savageduck:
BTW: Nothing personal, but your Usenet client seems to have a
problem with Unicode (UTF8) text encoding,

Nothing personal, but Usenet is an ascii text medium.

Hahaha! Yes, this is the level of ignorance that Floyd possesses! He
actually thinks that Usenet is *ASCII*.


--
Sandman[.net]

In article , Floyd L. Davidson wrote:

Eric Stevens:
If you want to argue with what he said then you have to use
the same meaning that he did.

nospam:
i used the common meaning of the term reversible.

Floyd L. Davidson:
Look up the common meaning of the term "reversible process", and
stop making absurd claims. Your problem is not knowing what we
are talking about, even now after all this discussion and effort
to explain it.

nospam:
i didn't say reversible process. you are twisting what i said as
well as lying.

i said usm is reversible with a non-destructive workflow.

that is a true statement, and not limited to just usm. again,
that's the whole point of a non-destructive workflow.

And off we go again with you using a different definition just to
confuse the issue.

It's the same definition. It's just that you have no idea what it means. No
surprise there.

The discussion is about how a high pass sharpen algorithm is a
"reversible process" and an unsharp mask algorithm is not.

If you use modern software, it's 100% reversible. Your kindergarden tools
need not apply.

nospam:
your problem is you can't admit that you have no idea about how a
non-destructive workflow actually works, so you pretend you do and
toss out some buzzwords like non-linear undo (which is laughably
wrong) and then try to claim it's only for cartoon characters.

you clearly spewing and also looking like an utter fool.

I am well aware of what a non-destructive workflow is and does, and
that is why I'm not doing something as stupid as relating it to a
non-reversible process such as the unsharp mask function.

Yes, you are ignorant, we know.

You do not seem to be able to differentiate the terminology required
to discuss the topic at hand. Apparently "Abobe for Dummies" doesn't
have even one paragraph, much less the necessary chapter, to help
you with that.

Ironic, when you don't even know what "reversible" means.

nospam:
he is using his own narrow definition and intentionally
dismissing *anything* else.

Floyd L. Davidson:
Because a typical dictionary may have 14 meanings for a word is
not a license for a reader to choose which one to abuse. The
*writer* chooses, not the reader.

nospam:
it seems you cannot discern between reading and writing.

*i'm* the one who said usm is reversible in a non-destructive
workflow, which makes *me* the writer. therefore, according to
you, i get to choose.

Kind makes you look less than astute. You did write that... after
you *read* a reference to "non-reversible functions". If you want
to respond to that you do not have the option of redefining the
terms.

Incorrect. When the original writer is ignorant about the English
language, it is the duty of us more knowledgable to steer the poor soul
correct by showing him examples of correct usage.

Now look up what a "reversible process" is. The term of art, not
the simple term.

Yes, please look it up. I've done so twice for you.


--
Sandman[.net]

On 18 Sep 2014 08:03:40 GMT, Sandman wrote:

In article , Eric Stevens wrote:

Floyd L. Davidson:
That is a good move on your part.
Start sticking with what Adobe calls it, and in the
process use appropriate terms.

nospam:
adobe didn't come up with the name. it's what
everyone calls it, because it's non-destructive.

Eric Stevens:
But that doesn't make the processes employed
reversible.

nospam:
who cares.

what matters is the results, not micromanaging every step of
the way.

a non-destructive workflow is reversible. period.

Eric Stevens:
So you accept that you are not talking about the same thing that
Floyd was talking about, and that you don't care.

Sandman:
Floyd has no idea what he's talking about, so as soon as someone
knows what they're talking about, they're by definition not
talking about whatever it is Floyd is babbling about.

On this occasion, at least, Floyd most certainly knows what he is
talking about.

Haha, no.

A problem seems to be that very few other people seem to.

Well, we all know that YOU rarely have the first clue about what you're
talking about, so I have no problem understanding why you're here
supporting ignorant Floyd.

Floyd's usage is strictly in accordance with
http://en.wikipedia.org/wiki/Reversi...rmodynamics%29
as it applies information theory. If you think there is no room for
reversible processes in information theory see
http://tinyurl.com/otp5pug
--

Regards,

Eric Stevens

On Thu, 18 Sep 2014 01:19:07 -0400, nospam
wrote:

In article , Eric Stevens
wrote:

That wasn¹t too tough to find:
Posted: Mon, 15 Sep 2014 13:44:18 -0500
Message ID:

Wherein Floyd stated the following:

³A non-destructive workflow means you can *undo* and then *redo*.

That is not a reversible 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.

If the sharpening is done with UnsharpMask that cannot
be done. USM is not reversible.²

Note, the words, ³save it as a JPEG,².

As I said, that genius Floyd did.

and that genius is completely wrong.

a non-destructive workflow doesn't 'destruct' so there's really nothing
to 'undo'.

all of the adjustments are done en masse, with the item in question
simply removed (or its parameters altered), which means it's never
'done'.

If it were never done, how come you think it can be undone?

it's not undone. it's redone with different parameters.

So, you are not reversing it: you are doing it again, but differently.

it's not a pixel level editor, it's a parametric editor.

do we have to go through the discussion about rendering again?
--

Regards,

Eric Stevens

On Wed, 17 Sep 2014 21:32:17 -0700, Savageduck
wrote:

On 2014-09-18 04:17:59 +0000, (Floyd L. Davidson) said:

Savageduck wrote:
On 2014-09-18 01:00:46 +0000, Eric Stevens said:

On Wed, 17 Sep 2014 06:05:14 -0700, Savageduck
wrote:
On 2014-09-17 09:22:00 +0000, Eric Stevens said:
On Tue, 16 Sep 2014 22:27:43 -0700, Savageduck
wrote:
On 2014-09-17 04:08:19 +0000, Eric Stevens said:
On Tue, 16 Sep 2014 07:53:15 -0700, Savageduck
wrote:
On 2014-09-16 10:36:29 +0000, (Floyd L. Davidson) said:

--- snip ---

The reverse process performed on a lossy, compressed JPEG is not going
to reverse the HPF to return to the original state. That was lost once
the save was executed.
That's why I never included a conversion to JPG in
my example of a
reversible process.
Â...but that genius Floyd did.

--- snip ---

No one who understood what we were trying to talk about would claim
that a JPG conversion is a reversible process.
Â...but that genius Floyd did.
I've had a look and I cant see where. Could you refer
me to the
message?

With pleasure.

That wasnâEUR(Tm)t too tough to find:
Posted: Mon, 15 Sep 2014 13:44:18 -0500
Message ID:

Wherein Floyd stated the following:

âEURoeA non-destructive workflow means you can *undo* and then *redo*.

That is not a reversible 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.

If the sharpening is done with UnsharpMask that cannot
be done. USM is not reversible.âEUR?

Note, the words, âEURoesave it as a JPEG,âEUR?.

As I said, that genius Floyd did.

So we now we know you can't read.

What I said was that *high pass sharpen is reversible*.
It is, even if a few people are unable to either understand
or accept that it is.

From a lossy, compressed JPEG?
You did say “save it as a JPEG” didn’t you?
Have you also developed the mathematics to reverse the compression and
loss in that High-Pass sharpened file, so that you can return it to its
original state?

HPS might well be reversible, but returning the file to its truly
original state after being saved as a JPEG is improbable.

It's not the file that is being returned to the original state: it's
the sharpening.

However, I have the tools to do that, with HSP, and even USM regardless
of how much you stamp your feet and say I can’t.

But you are not reversing it: you are reverting and replacing it. Not
the same thing.
--

Regards,

Eric Stevens

On Thu, 18 Sep 2014 01:19:09 -0400, nospam
wrote:

In article , Eric Stevens
wrote:

If you make the adjustments in Photoshop with a non-destructive
workflow there is no use of sidecar files or catalog entries as in
Lightroom.

True, but this has nothing to do with whether a process is
reversible or not.

Of course it does. Non-destructive adjustments means they are reversible.

Not in the strictly technical sense in which Floyd was using the term.

that's the whole problem.

floyd cannot acknowledge that there are other completely valid meanings.

If you want to argue with what he said then you have to use the same
meaning that he did.

i used the common meaning of the term reversible.

he is using his own narrow definition and intentionally dismissing
*anything* else.

Because the narrow meaning expresses *exactly* what he intends. Your
preferred broad meaning encompasses many alternatives. Hence this
argument.
--

Regards,

Eric Stevens

On Thu, 18 Sep 2014 03:44:23 -0400, nospam
wrote:

In article , Floyd L. Davidson
wrote:

If you make the adjustments in Photoshop with a non-destructive
workflow there is no use of sidecar files or catalog entries as in
Lightroom.

True, but this has nothing to do with whether a process is
reversible or not.

Of course it does. Non-destructive adjustments means they are
reversible.

Not in the strictly technical sense in which Floyd was using the term.

that's the whole problem.

floyd cannot acknowledge that there are other completely valid meanings.

If you want to argue with what he said then you have to use the same
meaning that he did.

i used the common meaning of the term reversible.

Look up the common meaning of the term "reversible
process", and stop making absurd claims. Your problem
is not knowing what we are talking about, even now
after all this discussion and effort to explain it.

i didn't say reversible process. you are twisting what i said as well
as lying.

But Floyd did.

i said usm is reversible with a non-destructive workflow.

Not in the sense of a reversible process.

that is a true statement, and not limited to just usm. again, that's
the whole point of a non-destructive workflow.

your problem is you can't admit that you have no idea about how a
non-destructive workflow actually works, so you pretend you do and toss
out some buzzwords like non-linear undo (which is laughably wrong) and
then try to claim it's only for cartoon characters.

you clearly spewing and also looking like an utter fool.

he is using his own narrow definition and intentionally dismissing
*anything* else.

Because a typical dictionary may have 14 meanings for a
word is not a license for a reader to choose which one
to abuse. The *writer* chooses, not the reader.

it seems you cannot discern between reading and writing.

*i'm* the one who said usm is reversible in a non-destructive workflow,
which makes *me* the writer. therefore, according to you, i get to
choose.

It may be for your definition of 'reversible' but it is not so in the
sense of the standard meaning of 'reversible process'.

not that i need to choose, since they all apply:
http://www.merriam-webster.com/dictionary/reversible
: able to be changed back to an earlier or original state

yes.

: able to be stopped and not causing permanent damage or changes

yes

: having two sides that can be used

if you consider raw and finished to be sides, then this works too.

definitely 2 out of 3 and arguably 3 out of 3.

it's reversible.
--

Regards,

Eric Stevens

On 18 Sep 2014 08:10:13 GMT, Sandman wrote:

In article , Eric Stevens wrote:

Eric Stevens:
The water is muddied by the several
applications which make use of a sidecar file of some kind
to preserve a list of edits which are only executed when the
image file is exported from the editing environment.
Modifying a sidecar file by deleting an editing process from
it does not make that process reversible. It merely makes
that process asthough it never was.

Savageduck:
If you make the adjustments in Photoshop with a
non-destructive workflow there is no use of sidecar files or
catalog entries as in Lightroom.

Eric Stevens:
True, but this has nothing to do with whether a process is
reversible or not.

Sandman:
Of course it does. Non-destructive adjustments means they are
reversible.

Not in the strictly technical sense in which Floyd was using the
term.

Yes, in a very strictly technical sense. In every sense of the word.

I disagree with you. Floyd disagrees with you. Leaving out the
question of native language, what experience or training have you had
to qualify you to dispute Floyd and my use of the term "reversible
process"?

Sandman:
A tip for the future - whenever Floyd says anything, it's a safe
bet to assume the exact opposite is true.

Not so, I'm afraid.

100% so.
--

Regards,

Eric Stevens