Blue Sky Nightmare (again)

  • Thread starter Thread starter Billman
  • Start date Start date
B

Billman

I posted questions about this problem with Vuescan before, and I
thought I had it solved, but I'm bumping into it again and wish I
could get some help in understanding what's going on. In particular,
I wish Ed could help identify what the color processing is doing to
produce this problem and how I could correct it. I haven't upgraded
to V8.0 yet - I only just learned about it when I went to post this
message.

The problem I am having is obtaining good scans when blue sky is a
significant part of the image. This time, I started by reseting the
Vuescan default options and changing only the scan mode and media type
for color negatives. The problem I'm experiencing is illustrated and
explained here:

http://www.intergate.com/~wcb/color/color.htm

The images look fine when the preview focuses on a normal landscape
scene, but becomes horrible when focusing on a blue sky picture. Does
anyone have any idea how to solve this problem?

Thanks -- Bill (w c b # trip - net)
 
Billman said:
I posted questions about this problem with Vuescan before, and I
thought I had it solved, but I'm bumping into it again and wish I
could get some help in understanding what's going on. In particular,
I wish Ed could help identify what the color processing is doing to
produce this problem and how I could correct it. I haven't upgraded
to V8.0 yet - I only just learned about it when I went to post this
message.

The problem I am having is obtaining good scans when blue sky is a
significant part of the image. This time, I started by reseting the
Vuescan default options and changing only the scan mode and media type
for color negatives. The problem I'm experiencing is illustrated and
explained here:

http://www.intergate.com/~wcb/color/color.htm

The images look fine when the preview focuses on a normal landscape
scene, but becomes horrible when focusing on a blue sky picture. Does
anyone have any idea how to solve this problem?
Click to expand...

Have you tried cropping a bit tighter (no edges included)? You can also try
an scan another image, shot under the same lighting conditions. If that
looks good, lock its image color and then scan this image.

Bart
 
Bill:

I'm not familiar with VS, but it appears that the mode you're using for the
images that fail tries to force a black-white point in the image. It's
obvious that the building images, for example, don't have a black and a
white.

Dane
 
Billman said:
The problem I am having is obtaining good scans when blue sky is a
significant part of the image. This time, I started by reseting the
Vuescan default options and changing only the scan mode and media type
for color negatives. The problem I'm experiencing is illustrated and
explained here:

http://www.intergate.com/~wcb/color/color.htm
Click to expand...

Try using the "Advanced Workflow Suggestions" in the VueScan
User's Guide.

You might also try clicking with the right mouse button (or holding
down the control key on Mac OS) to choose the neutral color.

Regards,
Ed Hamrick
 
Any reason why you are not happy with the Twain Driver and EPSON Scan
Utility v1.25A?
I have an Epson 3200 and we share the same Epson software. I also
have Vuescan. Most of the time I'm very pleased with the results from
Epson. It's faster and the quality is on par with Vuescan. Vuescan
does have a few other features like the ability to scan once but save
to multiple formats. I like Vuescan and it's my backup option when I
just can't get it right with Epson Scan Utility.
 
eastern said:
Bill:

I'm not familiar with VS, but it appears that the mode you're using for the
images that fail tries to force a black-white point in the image. It's
obvious that the building images, for example, don't have a black and a
white.
Click to expand...

The lower strip looks indeed like a typical case with Black Point > 0.
Vuescan reacts very radically to such cases where there is nothing
even close to black (lack of sanity check measure...)

What strikes me in these examples is though a lack of essential
information about setting: What is media type: slide, image. negative??
What is the selected color balance? What are White and Black point?
Please provide these details and I am sure that we can help.

For example regarding blue sky, Vuescan cannot deal well with images
containing almost only blue sky in conjunction with the White Balance.
Blue can be turned in a kind of lead-gray, literally. There again,
its a lack of sanity check in the algorithm. We spoke a while ago
that the one interesting notion of color adjustment is dealing with
what we consider memory colors (see Fraser's "Color Management").
Memory colors are colors which we consider real or not, based on
our subjective perception: skin tones, grass green, sky etc. etc.

Tools like Paint Shop Pro have even special buttons to inform
algorithms of a presence of skin tones etc. to prevent their
transformation into tones which we would perceive false.

Thomas
 
Have you tried cropping a bit tighter (no edges included)? You can also try
an scan another image, shot under the same lighting conditions. If that
looks good, lock its image color and then scan this image.
Click to expand...

I haven't tried that yet, Bart, but I'm willing to try anything.

Thanks - Bill
 
I'm not familiar with VS, but it appears that the mode you're using for the
images that fail tries to force a black-white point in the image. It's
obvious that the building images, for example, don't have a black and a
white.

Dane
Click to expand...

Thanks, Dane -- another responder mentioned the black-point setting -
I'll give this a try, too.

Bill
 
Any reason why you are not happy with the Twain Driver and EPSON Scan
Utility v1.25A?
I have an Epson 3200 and we share the same Epson software. I also
have Vuescan. Most of the time I'm very pleased with the results from
Epson. It's faster and the quality is on par with Vuescan. Vuescan
does have a few other features like the ability to scan once but save
to multiple formats. I like Vuescan and it's my backup option when I
just can't get it right with Epson Scan Utility.
Click to expand...

Hi, Dave --

My Epson TWAIN driver actually works great on images such as those I'm
having trouble with. I'm seeking help on my Vuescan issue because I
like the flexibility of VS, the generally great response I get from
it, and I like to get a routine workflow going when processing my
images (i.e., no flipping back and forth between scanning programs).

But perhaps I should just cut my losses timewise and go back to the
Epson drivers for these problem images.

Bill
 
Thanks, Thomas --

All of my settings were those that Vuescan resets to with when
selecting the "Default Options" from the File menu. The only settings
I changed were "Transparency" and "Color Negative" - everything else
was "default". Which means that the color mode was "white balance", so
perhaps that is a source/contributor to the problem. I've experience
this:
Blue can be turned in a kind of lead-gray, literally.
Click to expand...

quite frequently with Vuescan+Blue Sky (much to my chagrin).

I'll experiment some more with black point/white point and see what
happens.

Thanks,

Bill
 
Thanks, Ed --

I use the Advanced Workflow process already to lock exposure and lock
film color base, but still got bad these bad scans. And I haven't had
any better luck selecting nuetral colors. I'll try them again from
the default settings and see what happens, but I have a feeling that
these are not the problems. Thomas' suggestions about the black point
and white balance may be more in the right direction of solving the
problem.

I also wonder about the fact that I haven't heard from or seen a
response from anyone that hass experienced or is experiencing the same
problem with Vuescan. Am I the only one having this trouble, and if
so what is it that I don't know? Hmmmm ....

Thanks,

Bill
 
I'd like to wrap up this thread by sharing that I've finally been
successful at getting good scans of Blue Sky images!! :-) (And there
was great rejoicing!)

What I did different was as follows:

(1) Loaded Vuescan 8.0.1
(2) Followed the recommended advanced workflow: preview->Lock
Exposure->preview->Lock Film Color Base-> Lock Image Color.
(3) Used the workflow on a complete, well-exposed image in the strip
rather than on a blank/black strip of film.

I don't know how much of an effect that this last step, (3), had on
what I was experiencing. I'd always followed the workflow on a
blank/black strip of film, but it was late and I was tired so I took
the lazy route and followed the workflow on a complete image rather
than zoom in a blank area.

Anyway, I'm finally getting the results I think I should be getting,
so thanks for all your help everyone.

Bill
 
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