Basic question about Vuescan and color...

[Daniel Masse]

Hello !

I have been playing with Vuescan for a while, scanning slides on my Nikon
Coolscan IV. Until now, I chose "White balance" most of the times. But I am
getting tired of having to correct colors in PS... There must be a quicker
way of doing it...

One thing I do not understand : at the end of the scanning process, the
colors seem to be quite nice. Then Vuescan corrects the colors, probably in
accordance with the color balance I have set. Yet, I cannot prevent Vuescan
from correcting the colors, even by setting "no color balance".

My monitor is profiled, and I have entered the monitor color profile into
Vuescan.

I must have missed a point... Is there a good tutorial on color management
in Vuescan somewhere ?

Thanks !

 

[Mendel Leisk]

Hello !

I have been playing with Vuescan for a while, scanning slides on my Nikon
Coolscan IV. Until now, I chose "White balance" most of the times. But I am
getting tired of having to correct colors in PS... There must be a quicker
way of doing it...

One thing I do not understand : at the end of the scanning process, the
colors seem to be quite nice. Then Vuescan corrects the colors, probably in
accordance with the color balance I have set. Yet, I cannot prevent Vuescan
from correcting the colors, even by setting "no color balance".

My monitor is profiled, and I have entered the monitor color profile into
Vuescan.

I must have missed a point... Is there a good tutorial on color management
in Vuescan somewhere ?

Thanks !

I've just started experimenting with Coloraid.de 35mm targets with my
Elite 5400 and Vuescan. Following the guidance in the Vuescan html for
calibrating scanner, my results after producing and using the icc
profile in:

Color|Scanner ICC Profile

Where much improved, and much closer to the original slide.

With the Vuescan generated profile on, I set:

Color|Color Balance to "neutral".

The side benefit of being able to use neutral without having apparent
color cast, it doesn't mess with the color balance, as "white balance"
will.

I'm just now playing with XLProfiler also, but still, got quite good
results thru the Vuescan calibration of scanner workflow.

Good luck.

 

[Daniel Masse]

I've just started experimenting with Coloraid.de 35mm targets with my
Elite 5400 and Vuescan. Following the guidance in the Vuescan html for
calibrating scanner, my results after producing and using the icc
profile in:

Color|Scanner ICC Profile

Where much improved, and much closer to the original slide.

Yes : I believe I'll have to profile my scanner too.

One question remains. Vuescan works in two steps : scan, then color
adjustment accordng to the settings.

My question is : how to get Vuescan not to apply these adjustments, and just
leave the colors as they are after the scan ? When I set "no color balance",
I still get a significant color change.

 

[Don]

One thing I do not understand : at the end of the scanning process, the
colors seem to be quite nice. Then Vuescan corrects the colors, probably in
accordance with the color balance I have set. Yet, I cannot prevent Vuescan
from correcting the colors, even by setting "no color balance".

There's a long standing VueScan bug where the Preview doesn't
correspond to the resulting scan.

The INI file inevitably goes corrupt very quickly if you make any
changes. Try deleting it and then using "none" as color balance.

If that doesn't work, there's another major VueScan problem in that
various (hidden) options interact in weird and secretive ways.
Starting with a new INI may temporarily "cure" that - at least until
you start making changes again. So, at first don't change anything
else besides "none".

Finally, VueScan is notoriously buggy. You may want to try a different
version and see if that makes any difference.

Don.

 

[Leonard Evens]

Hello !

I have been playing with Vuescan for a while, scanning slides on my Nikon
Coolscan IV. Until now, I chose "White balance" most of the times. But I am
getting tired of having to correct colors in PS... There must be a quicker
way of doing it...

One thing I do not understand : at the end of the scanning process, the
colors seem to be quite nice. Then Vuescan corrects the colors, probably in
accordance with the color balance I have set. Yet, I cannot prevent Vuescan
from correcting the colors, even by setting "no color balance".

Vuescan has a useful feature. If you right click on a neutral area, it
will adjust the color balance so that area is a neutral gray without
changing its general value. Often this will get you very close. In
addition afterwards, you are in manual mode. You can further adjust
color balance by fiddling with the sliders. I use the neutral red and
neutral blue sliders for that. Setting the white point with the
histogram helps adjust the overall density range. Using these methods
I usually come quite close to what I want and if necessary I make
further adjustments in my photoeditor. I work under Linux and use the
Gimp for editing. I have done an overall grayscale calibration of my
monitor but nothing beyond that. I haven't profiled my Epson 3200
scanner. I see no difference between what the Vuescan viewer shows me
and what the Gimp shows me.

Scenes don't always have neutral areas although it is surprising how
often you can find one if you look. For that purpose I use reference
densities I've saved for typical other scene colors such as sky, grass,
skin tone, etc. By using such references you can get pretty close to
what you want. I've found that the most important thing about reference
colors is that the order of the magnitudes is right. If the color
should be G<B<R, you don't want to see B<G<R. Beyond that, while the
RGB values do play a role, often it is the differences that are more
important than the actual values.

I also use a digital camera to photograph the scene with a gray card in
it and that helps me determine what the values for other parts of the
scene should be. In your case, you can just take another picture with a
gray card in it.

One important thing I learned from "Professional Photoshop" by Dan
Margulis is that you can never get all the colors exactly right. It is
more important the crucial colors should be plausible, so there is
always a matter of balancing one consideration against another.

 

[Daniel Masse]

There's a long standing VueScan bug where the Preview doesn't
correspond to the resulting scan.

Yes, I was aware of that. My question was : why does the color of the scan
display change, even if I set the color balance to "none" ?

The INI file inevitably goes corrupt very quickly if you make any
changes. Try deleting it and then using "none" as color balance.

I tried that, but it did not work...

Thanks, Don !

Color management is definitely a very very complicated matter... But I'll
get the results I want - eventually...

 

[Daniel Masse]

Vuescan has a useful feature. If you right click on a neutral area,
it will adjust the color balance so that area is a neutral gray
without changing its general value. Often this will get you very
close. In addition afterwards, you are in manual mode. You can
further adjust color balance by fiddling with the sliders. I use
the neutral red and neutral blue sliders for that. Setting the white
point with the histogram helps adjust the overall density range. Using
these methods I usually come quite close to what I want and if
necessary I make further adjustments in my photoeditor. I work
under Linux and use the Gimp for editing. I have done an overall
grayscale calibration of my monitor but nothing beyond that. I
haven't profiled my Epson 3200 scanner. I see no difference between
what the Vuescan viewer shows me and what the Gimp shows me.

That's RIGHT ! I had seen that feature, but I forgot to try it. It is indeed
very helpful, almost good.

Thank you !

 

[Don]

I tried that, but it did not work...

Sorry to hear that... :-(

Color management is definitely a very very complicated matter... But I'll
get the results I want - eventually...

I'm stubborn like that too. ;o)

BTW, I was going to suggest using raw, but then you don't get color
management if I remember correctly (I don't use VueScan). Anyway, good
luck!

Don.

 

[Erik Krause]

Yes, I was aware of that. My question was : why does the color of the scan
display change, even if I set the color balance to "none" ?

One reason could be if you set Media Type (Input tab) to Slide film
vuescan tries to determine the film base color. It needs a clear part
of film to do this, which most likely is not present in a slide. Set
Media Type to Image. Media Type Slide is only usable with advanced
workflow (see manual).

Another reason could be if you checked Restore Colors or Restore Fading
on Filter tab.

I use Vuescan all the time to scan for panorama stitching - where
there should be not the slightest color deviation between adjacent
images - with good success.

 

[Don]

Vuescan has a useful feature. If you right click on a neutral area, it
will adjust the color balance so that area is a neutral gray without
changing its general value.

All scanning software can set the gray point. That's pretty basic.

However, setting the gray point (or any other editing) is really the
domain of image editing and it's better done there i.e. after the
scan. Not only does dedicated image editing software do a better job,
but with all of the other tools it's much more accurate. For example,
instead of a small 3x3 matrix one can select large neutral areas and
average them, or use curves instead of blunt levels gray point, etc.

Don.

 

[Mendel Leisk]

Don't know if I can answer your last correction directly. I do know I'm
continuing to improve my color balance by:

1. Using the ICC profile I generated with Vuescan's calibrate scanner
function.

2. Scanning the IT8 target I used to make the profile, WITH the Scanner
ICC Profile activated, and right-clicking on patch 9 of the target
which appears to be the neutral gray zone (along with the entire border
of the target). I actually did this several times, then manually typed
in the average of all my samples, for each of the 3 (neutral
red/green/blue) fields.

3. Scanning-from-disk my image files with the Scanner ICC Profile in
use, and with Manual Color balance, with the settings established in
step 2.

 

[simplicity]

I've just started experimenting with Coloraid.de 35mm targets with my
Elite 5400 and Vuescan. Following the guidance in the Vuescan html for
calibrating scanner, my results after producing and using the icc
profile in:

Color|Scanner ICC Profile

Where much improved, and much closer to the original slide.

With the Vuescan generated profile on, I set:

Color|Color Balance to "neutral".

The side benefit of being able to use neutral without having apparent
color cast, it doesn't mess with the color balance, as "white balance"
will.

I'm just now playing with XLProfiler also, but still, got quite good
results thru the Vuescan calibration of scanner workflow.

Good luck.

The slide profile that comes with the 5400 works just fine with the
Minolta native sw. Using that profile, my raw scans viewed in PS are
very close to the original.

Scans corrected by a scanner's sw (auto or manual) can mess up the image
looks and can lead to wrong and unnecessary solutions. It is a crap
shoot much like letting a camera's auto exposure take control. Scan raw
and you at least start at a known state.

 

[Daniel Masse]

One reason could be if you set Media Type (Input tab) to Slide film
vuescan tries to determine the film base color. It needs a clear part
of film to do this, which most likely is not present in a slide. Set
Media Type to Image. Media Type Slide is only usable with advanced
workflow (see manual).

No, I always use "image" when I scan slides

Another reason could be if you checked Restore Colors or Restore
Fading on Filter tab.

I never did check these boxes...

I use Vuescan all the time to scan for panorama stitching - where
there should be not the slightest color deviation between adjacent
images - with good success.

Until now, I always used Vuescan without paying that much attention to the
colors : I make the corrections within PS. But I just had to scan a bunch of
slides, and I tried to save some time by getting the scans closer to the
true colors. Now, I am using the method suggested by Leonard, and I am
getting better results.

Still, I am quite curious to find out the reason why I cannot retain the
colors displayed in the original scan (a color change always occurs, even
when I specify "none").

 

[Erik Krause]

Still, I am quite curious to find out the reason why I cannot retain the
colors displayed in the original scan (a color change always occurs, even
when I specify "none").

Vuescan converts the colors into the chosen output color space (color
tab). I never found out why the display changes if I use another output
color space (which should affect the file data only). If you want to
see what vuescan shows during scanning, you should try 'Device RGB' and
color balance None. At least this worked for me.

 

[Jeff Randall]

Dan:
What version of VueScan are you using? Maybe I missed it, but what
scanner are you using?

If you are scanning with the Pref tab Display raw scan checked and
Input tab Lock exposure unchecked, then when you press Preview, the raw
scan is output to the screen and if you select Color tab Color balance
None then VueScan applies the Color balance (in this case None). The
"corrected" preview image should be the same as the raw. Look at the
Preview histogram. The upper is the raw and the lower is the corrected
-- they should look *similar*. If you check Lock exposure and press
Preview again, the preview will look different because the first
Preview was made with Exposure = 1, the second with what ever VueScan
determined to be the correct exposure during the first Preview.

If you really want no color correction, check the Output tab Raw file.
If you scan at 48-bits then the raw gamma will be = 1. If you scan at
24-bit, the raw gamma will be = 2.2.

Jeff Randall

 

[Jeff Randall]

Another thought...Are you sure that the Color tab brightness and
brightness R, G, and B are set = to one as well as setting Color
balance to None? If not the final preview image (after applying the
Color tab settings) will be different from the temporary raw image that
is output to the screen during preview scanning.

jr

 

[keyes04]

There's a long standing VueScan bug where ....

The INI file inevitably goes corrupt very quickly ....

If that doesn't work, there's another major VueScan problem ....

Finally, VueScan is notoriously buggy.

Don.

Don,

I just don't understand why these people won't listen to you. Ed
needs to get his army of software engineers to earn their pay, and get
his marketing department to do a better job. I mean, look at what
Bill Gates has done by getting all of his engineers and marketing
folks in line! Even more sales of flawless and effortless software
for the masses, and therefore more customers than ever before, with
Microsoft software still being considered the "standard." If Ed works
his large staff harder and smarter, he too might produce the same high
quality, reliable software as Bill Gates does with his equally large
staff.

C.R.

(Happy owner of an old Epson 1650, and a Nikon Coolscan V that doesn't
know it's not supposed to operate with VueScan - kinda like a
bumblebee doesn't know it can't possibly fly.)