Vuescan - new features

[Don]

As long as you can see the effect of your adjustments in the final image
(gamma 2.2) this is not a problem, and certainly not a bug.

The fact that you see the result is totally beside the point.

If, according to Bart, Vuescan uses one image (at 2.2) to set the
curve point and then applies it to another image (at 1.0) then it's a
major bug! (See message to Roger for details.)

I'm all for lateral thought and eccentric thinking, but what possible
use can there be for this bug? It just doesn't make any sense.

Don.

 

[Noons]

Pasi Savolainen apparently said,on my timestamp of 2/12/2005 5:03 AM:

the result in 8bit (for those of us without access to stable 16bit aware
applications *cough*GIMP*cough*).

Aye! Too right...

 

[Noons]

Mendel Leisk apparently said,on my timestamp of 1/12/2005 4:06 PM:

I found simply bumping the numbers from default 25/75 to 20/80 worked
very much like PS shadow/highlight: recovered shadow detail in
moderately underexposed slides, along with improved highlight.

Which numbers are these?

 

[Mendel Leisk]

Not at home, so going from memory, they're in the color tab, and are
related to the new curves feature. They are in two *new* fields there.
Hovering the mouse over them gives a bit of explanation.

The defaults are 25% and 75% and these settings yeild a straight 45
degree line in the curve display. Setting them to (say) 30% and 70%
yields a more aggressive contrast s-curve. Setting them to (say) 20%
and 80% does the inverse, reducing contrast a bit.

Which histogram you're going to see depends on another new setting, int
the Prefs tab.

 

[Philip Homburg]

If, according to Bart, Vuescan uses one image (at 2.2) to set the
curve point and then applies it to another image (at 1.0) then it's a
major bug! (See message to Roger for details.)

I have simple XYZ library that basically does the same thing: the image
is kept in XYZ (which implies linear luminance) and the result is of course
displayed after the appropriate color space transformations and gamma
correction.

Any correction I specify is in the XYZ, but the the results only become
visible in sRGB (with avg gamma 2.2).

 

[Bart van der Wolf]

Not at home, so going from memory, they're in the color tab,
and are related to the new curves feature.

Correct, but they only show when Advanced options on the color tab are
selected.

Bart

 

[Daniel]

It is total jerkoffs like you that prompted Ed to stop contributing to this
group,
so those of us who genuinely need advice cannot get it.

Go away jerk

 

[Wilfred]

I have simple XYZ library that basically does the same thing: the
image is kept in XYZ (which implies linear luminance) and the result
is of course displayed after the appropriate color space
transformations and gamma correction.

Any correction I specify is in the XYZ, but the the results only
become visible in sRGB (with avg gamma 2.2).

And AFAIK that's also what Photoshop does - as 'Don' carefully ignored
in my message he replied to:

(I wrote

If you do a curves adjustment in Photoshop, you are manipulating the
image in its own color space (e.g., Adobe RGB). Yet, if you are
working with a monitor profile, Photoshop converts the image for
display to your monitor space. This would be exactly the same 'bug',
since you're not manipulating in the same color space as the image on
the monitor is!

(by the way, if VueScan is configured correctly, it will also produce
a displayed image converted to your monitor space. Yet another
'bug'!)

There's no sense in arguing with Don - he reacts selectively and ignores
the arguments he cannot refute.

 

[Evo2Me]

There's no sense in arguing with Don - he reacts selectively and ignores
the arguments he cannot refute.

Since when can Don refute anything - or want to? When I put him into
my killfile I did not because I don't like dissenting opinions but
because he's nothing more than a zealot [religious allusion
intentional] on his war path against Mr Ed Hamrick and his program.

 

[Philip Homburg]

(I wrote

But Adobe98 is 2.2 and most monitors are also 2.2. So from a luminance
point of view, you are manipulating what you see on the screen.

 

[Don]

I have simple XYZ library that basically does the same thing: the image
is kept in XYZ (which implies linear luminance) and the result is of course
displayed after the appropriate color space transformations and gamma
correction.

Any correction I specify is in the XYZ, but the the results only become
visible in sRGB (with avg gamma 2.2).

It's apples and oranges. I'm afraid you're missing the point, Philip.
The *display* of the final result is totally irrelevant. It's how the
edit is applied:

The settings are *established* using one image.
They are *applied* to a totally different image.
*No* conversion takes place!! <= That makes it a bug in this context!

As I explained in my message to Roger which you seem to have ignored
even though I specifically drew attention to it:

If, for example, you select a curve point based on gamma 2.2 image and
this is e.g. at bin 128, in gamma 1.0 version of the image this point
is roughly at bin 56.

Therefore, applying this "128 curve" without conversion to an image
where the desired data is actually at 56, is a bug!

Don.

 

[Don]

And AFAIK that's also what Photoshop does - as 'Don' carefully ignored
in my message he replied to:

Because it's totally irrelevant and has nothing to do with this
Vuescan bug (as implied by Bart).

(I wrote

But Photoshop *does the conversions* as required!!! Conceptually
that's *not* what's happening with Vuescan, according to Bart!

The comparable case would be if any changes you made in Photoshop are
*not* profile corrected before being applied!!! That's the point!

With Vuescan you're apparently basing editing decision on one image,
and then applying them to a totally different one *without* taking
into account the differences or doing the necessary conversions.

Don.

 

[Don]

But Adobe98 is 2.2 and most monitors are also 2.2. So from a luminance
point of view, you are manipulating what you see on the screen.

Exactly! And even if you didn't Photoshop would do the necessary
conversions both ways.

Don.

 

[Djon]

The graph seems to serve no particular purpose beyond entertainment,
but time will tell...maybe someone will find a use.
Not a problem.

I've been very pleased with Vuescan for a year or so. I delay upgrades
and try to stay behind the curve, just to avoid cutting-edge
thrills...I'm that way with all applications.

I currently use Vuescan on two scanners, a Nikon V and an old Epson
3200 that's got custom carriers and is quite adequate for prints from
MF and LF. Unfortunately the 3200 won't impliment Vuescan's infared,
which works so well with Nikon (Nikon V has 4 LEDs, one of which is
infared/Ice).

 

[DaveG]

(as implied by Bart).

according to Bart!

This has to be the funniest thread I've read in long, long time. Every
time you refute someone or make a claim, you qualify it blaming it on
something Bart might have said,

Have you looked at it yourself? Or are you happy to base your entire
argument on hearsay?

 

[Bart van der Wolf]

This has to be the funniest thread I've read in long, long time.
Every
time you refute someone or make a claim, you qualify it blaming it
on
something Bart might have said,

And what's worse, he apparently didn't (want to) understand a single
bit of it, in a futile attempt to either discredit me (by attributing
things that I never said), or VueScan. His MO is so predictable...,
yawn.

I don't know what provokes his childish behavior, but such a Jihad it
is sad, rather than funny IMO.

Have you looked at it yourself?

Rethorical question? ;-)

Bart

 

[Philip Homburg]

The settings are *established* using one image.

What do you mean 'settings are established using one image'?

Typically in a curves window, you can just select a point on the
curve, and move it up or down. The uncorrected image does not appear as
input.

There is a second method, where you select a point on the image, and the
value of that point gets transferred to the curves window. It is possible that
Vuescan fails to apply gamma in this case, but that is just a one line fix.

If, for example, you select a curve point based on gamma 2.2 image and
this is e.g. at bin 128, in gamma 1.0 version of the image this point
is roughly at bin 56.

If you select bin 128 in the window, then yes, you may end up changing bin
56 in the 2.2 gamma corrected image. But the 2.2 gamma correct image is only
there to display what you are doing. The real image is in gamma 1.0.

Therefore, applying this "128 curve" without conversion to an image
where the desired data is actually at 56, is a bug!

You 'cannot' display a gamma 1.0 image directly. So, in all likelihood,
when you select 128 the right thing is going happen: the curve (with 128 moved)
gets applied to the linear gamma image. Then a gamma of 2.2 is applied and the
results is shown on the screen.

 

[Don]

What do you mean 'settings are established using one image'?

You use the image to determine where to set the point. For example, by
sampling a gray point or averaging out an area of interest, etc.

Typically in a curves window, you can just select a point on the
curve, and move it up or down. The uncorrected image does not appear as
input.

Yes, you can set points directly (i.e. blind) in the curve but that's
a very blunt instrument. Doing that means making assumptions about the
image. For example, using the "standard" S curve (64,128,192) assumes
where the shadows, midtones and highlights are.

However, even in that case, basing this "blind" setting on a gamma 2.2
image while the curve is applied to a gamma 1.0 image doesn't get
around that root problem.

There is a second method, where you select a point on the image, and the
value of that point gets transferred to the curves window.

Yes, that's what I'm talking about.

It is possible that
Vuescan fails to apply gamma in this case, but that is just a one line fix.

It wouldn't be the first time that Vuescan fails to do the simplest of
things which is precisely why it can be justifiably described as buggy
and unreliable.

If you select bin 128 in the window, then yes, you may end up changing bin
56 in the 2.2 gamma corrected image. But the 2.2 gamma correct image is only
there to display what you are doing. The real image is in gamma 1.0.

Which is precisely the root of the problem, apparently.

You 'cannot' display a gamma 1.0 image directly.

I notice quotes around 'cannot' which means you know what I'm going to
say (so just ignore the next bit) but for the benefit of kibitzers:

Actually, one can. That's what linear editing is all about. One simply
recalibrates the monitor to gamma 1.0 as well and then the image does
not appear "dark and contrasty".

So, in all likelihood,
when you select 128 the right thing is going happen: the curve (with 128 moved)
gets applied to the linear gamma image. Then a gamma of 2.2 is applied and the
results is shown on the screen.

Of course, if that were the case, then yes. But that's not what was
reported.

But even in that case looking at one image while editing another (in
the current context) is just asking for trouble. But such convoluted
contraptions are one of the major trademarks of Vuescan and why it is
so buggy and unreliable.

Don.

 

[Don]

Every
time you refute someone or make a claim, you qualify it blaming it on
something Bart might have said,

There is no "blame". It's called identifying one's source,
substantiating one's statements, and establishing the context.

In a word, being objective.

Judging by the above, it's a concept you have extreme difficulty
grasping.

Have you looked at it yourself?

I don't use Vuescan. But, yes, I have evaluated/looked at it in the
past and it was as appalling as it is now.

Or are you happy to base your entire argument on hearsay?

Do you realize you have just insulted Bart by accusing him of gossip?

I suggest you check your definition of "hearsay" (a hint: unknown
and/or unsubstantiated source, gossip).

*In general*, I don't consider Bart's postings "hearsay" and I have
said so many times. Quite the contrary! I consider many of Bart's
messages very valuable with one important caveat:

Namely, he does have one big problem in that he's totally uncritical
of Vuescan (an irrational apologist, really) and has frequently posted
blatantly contradictory statements. For example, after vigorously
"defending" Vuescan for months he inadvertently let it slip he doesn't
actually use it to scan because of the bugs.

Nevertheless, that doesn't prevent me from giving credit to some of
his other messages and/or taking them seriously.

Again, it's called being objective.

Don.

 

[DaveG]

There is no "blame". It's called identifying one's source,
substantiating one's statements, and establishing the context.

In a word, being objective.

Judging by the above, it's a concept you have extreme difficulty
grasping.
No.


I don't use Vuescan. But, yes, I have evaluated/looked at it in the past
and it was as appalling as it is now.

Right. So being objective means arguing your point based on someone elses
experience.

Do you realize you have just insulted Bart by accusing him of gossip?
Wrong.

I suggest you check your definition of "hearsay" (a hint: unknown and/or
unsubstantiated source, gossip).

hear·say
n.

1. Unverified information heard or received from another; rumor. 2.
Law. Evidence based on the reports of others rather than the personal
knowledge of a witness and therefore generally not admissible as
testimony.

So, how exactly have you verified your source?