ICC Profile/calibration need for b/w negative scanning?

[David Meriwether]

Please clear my confusion. I have an Epson 1280, use vuescan pro. I
scan 4x5 b/w negatives exclusively. My scans of standard 21 step
negative are universally unbalanced regardless of adjustments of bp/wp
(as little as .01) /brightness (lots of variations in combination with
changes of film CI on TMAX 100), film type (I tried several), etc.
Last 3 or 4 steps register 240+ in most cases. No change whether I
scan as 48 rgb or 16 gray. Both tif and raw files show problem (though
opposite appearance since one is positive conversion, other negative).
In terms of result, highlights are completely blown out, no subtlety
at all. As a photographer, the way I would describe the problem in the
darkroom is that the negatives are underexposed, causing shadows to be
too light, highlights lost.

I think I need to calibrate the scanner, but it is not a problem of
color, more exposure. It seems also that the bp/wp/brightness
adjustments would constitute the density calibration. In Vuescan, is
'brightness" equivalent to gamma? I have never profiled this scanner
with it8, etc., and use "built in" as the preference. Will it8
calibration/profile help? Seems like it should but Epson flat beds are
strange. What am I missing here? Any suggestion, advise or direction
would be appreciated.

 

[-]

Just a suggestion, but are you sure your monitor is properly calibrated so
that you can be assured that your monitor is accurately representing the
actual data?

Doug

 

[Robert Feinman]

Please clear my confusion. I have an Epson 1280, use vuescan pro. I
scan 4x5 b/w negatives exclusively. My scans of standard 21 step
negative are universally unbalanced regardless of adjustments of bp/wp
(as little as .01) /brightness (lots of variations in combination with
changes of film CI on TMAX 100), film type (I tried several), etc.
Last 3 or 4 steps register 240+ in most cases. No change whether I
scan as 48 rgb or 16 gray. Both tif and raw files show problem (though
opposite appearance since one is positive conversion, other negative).
In terms of result, highlights are completely blown out, no subtlety
at all. As a photographer, the way I would describe the problem in the
darkroom is that the negatives are underexposed, causing shadows to be
too light, highlights lost.

I think I need to calibrate the scanner, but it is not a problem of
color, more exposure. It seems also that the bp/wp/brightness
adjustments would constitute the density calibration. In Vuescan, is
'brightness" equivalent to gamma? I have never profiled this scanner
with it8, etc., and use "built in" as the preference. Will it8
calibration/profile help? Seems like it should but Epson flat beds are
strange. What am I missing here? Any suggestion, advise or direction
would be appreciated.

I would try setting black and white clipping values to 0. The idea
is to capture all the data from the scanner then do your adjustments
in your image editor.
I have a couple of tips on scanning black and white on my web site
which you might want to try out.
Follow the tips link on my home page..

 

[David Meriwether]

Thanks for the suggestions so far, but the monitor is calibrated, set
to 5000 and gamma 1.8, etc. for a Mac.

On the clipping, I assume you mean exposure clipping, and it is set at
0. Part of the difficulty here is that Vuescan has several interacting
settings (example, bp/wp/brightness, then CI for film type) and the
documentation is not clear about how they interact.

I used the Epson software and have the same problem, which leads me to
think that there is some defect, shortfall, etc., of the 2450 to deal
with dense sections of negatives (dmax etc). Photographically
speaking, it is underexposing the negative. A professional
photographer / digital photographer with a national reputation for
technical ability is having the same problem with a new 3200.

I'm looking for a way to profile the scanner to start from a full
black/white and even step grays, but I cannot achieve that with the
industry standard negative. If I can't get it from any software, then
is it my scanner or all Epson scanners? Just questions to prompt
someone else to think of a solution.

 

[Erik Krause]

Hello, David Meriwether
you wrote...

I think I need to calibrate the scanner, but it is not a problem of
color, more exposure.

Does your scanner support CCD exposure adjustment? If yes, did you try
'long exposure pass'?

It seems also that the bp/wp/brightness
adjustments would constitute the density calibration. In Vuescan, is
'brightness" equivalent to gamma?

Yes. It's a multiplier for the color space gamma.

I have never profiled this scanner
with it8, etc., and use "built in" as the preference. Will it8
calibration/profile help?

No, most probably not. Density problems can not be solved by profiling.
And there is no way to profile for negative film since there are no
targets available.

Seems like it should but Epson flat beds are
strange. What am I missing here? Any suggestion, advise or direction
would be appreciated.

You say the effect is visible in raw files, too? Notice that raw is in
gamma 1.0 space. You will have to adjust manually for 2.2 (windows) or
1.8 (Mac) to judge it. If there are still missing tones in the shadows
(negative) your scanner simply is not capable of scanning the high
density of your film. If long exposure pass does not work, there will
be no way to improve it.