Vuescan Buffer Percentage and Black Point

  • Thread starter Thread starter Alan Smithee
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A

Alan Smithee

Why is it that when scanning Black and White negatives Crop | "Buffer
Percentage" seems to do more to affect the outcome of my black point than
adjusting the RGB Exposure? When I lock my RGB exposure at 1.0 why does the
program still respond to the "Crop | Buffer %" option? Shouldn't it cease to
work especially since I'm in a B&W mode?
 
Buffer ignores a strip around the edge of the image, the width of that
strip determined by what you type into buffer %. If there is an extra
bright or dark area in this zone, it will be clipped. It's typically to
ignore the film holder or edge of slide, but it usually enchroaches
into the image as well.
 
Mendel said:
Buffer ignores a strip around the edge of the image, the width of that
strip determined by what you type into buffer %. If there is an extra
bright or dark area in this zone, it will be clipped. It's typically
to ignore the film holder or edge of slide, but it usually enchroaches
into the image as well.
Click to expand...

Yes it's suppose to ignore a certain area IF I'm letting Vuescan calculate
exposure (sic from the docs "Color balance" for colour films), remember I'm
scanning B&W not colour. But if I'm locking down my RGB exposure I don't
want the program to adjust the exposure which is what it "appears" to be
doing. In my case I have to adjust this setting to near 0% or zero% (the
default is 20%) or Vuescan clips the dark areas of my negative, (or, more
accurately, just cuts the shadows to close for my liking).
 
Alan Smithee said:
Why is it that when scanning Black and White negatives Crop | "Buffer
Percentage" seems to do more to affect the outcome of my black point than
adjusting the RGB Exposure? When I lock my RGB exposure at 1.0 why does the
program still respond to the "Crop | Buffer %" option? Shouldn't it cease to
work especially since I'm in a B&W mode?
Click to expand...

RGB exposure is the exposure of the CCD sensor. This is a pure hardware
setting and if you have locked it, it will not be changed.

However, if you do not lock image color (or set white balance to
'None') then black and white point are determined from the area which
is affected by the buffer setting (which is part of the post processing
vuescan does). Simply lock image color if you don't want this
behaviour.

I'm not sure whether you should lock RGB exposure to 1.0 since this
might be much too low to look through the densest parts of your neg's.
A better idea is to determine a value using 'advanced workflow' (see
manual)...
 
Why doesn't Vuescan have a "moderated" list somewhere?
Click to expand...

Two reasons, really:

1. The author can't handle objective, fact-based reality.
2. The author can't be bothered with what users think or want.

!=> Even a semi-reputable software manufacturer would provide such a
forum on their site!

Oh yes, one more:

3. Most Vuescan "fans" prefer to shoot the bearer of bad news rather
than demand that (at least some of) the many Vuescan bugs be fixed.

There is the *unmoderated*:

alt.comp.periphs.scanners.vuescan

Also, I believe (but don't know for sure) that anyone can create a
Google group which can even be made by "invitation only" i.e. closed.

!=> Alternatively, one of the "many" alleged Vuescan "professional"
users could surely host such a forum on their company's site.

That would take a fraction of the effort they put into obsessively
attacking anyone daring to point out objective facts about Vuescan.

Either way, sounds like a excellent idea to me! ;o)

Don.
 
Honestly a public forum would scare people away from Vuescan.
The latest version has significant cropping bugs with my scanner where
it forgets the cropping settings from prescan to scan and the IR fails
as well... That's progress!
 
Honestly a public forum would scare people away from Vuescan.
The latest version has significant cropping bugs with my scanner where
it forgets the cropping settings from prescan to scan and the IR fails
as well... That's progress!
Click to expand...

That's why the author was never keen on a dedicated public support
forum. Indeed, all that would do is expose even more Vuescan problems
and further demonstrate his inability to fix them.

Which is why he theatrically "resigned" from here so he doesn't have
to answer to such amateur bugs (like the one above) in the... what is
it now... *8th* major version?

Instead, he lurks and occasionally posts glorious praises to his own
program under a fake name...

Don.
 
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