Manual Exposure

[marcopaci]

Hi all,
I'm a newbie to Silverfast SE Plus 8. I'm using also an Epson V850 pro.
I scan 4x5 negatve film to apply Ansel Adams Zone system.
I want my scan tone values are based only on film densities and consistent across frames.
Scanning some stouffer calibration film I noticed that the tones associated to a certain film densities change from film to film depending on the Drange of the film I'm scanning.
How could I surpass this condition?
Can anyone give me a procedure to manually determine the scanning exposure using Silverfast, so that it can be consistent for different films?
Thank you in advance
Marco Paci

[LSI_Ketelhohn]

Dear Marco,

you can deactivate the NegaFix auto adjustment by removing the mark from the auto checkbox in the Negafix settings.
First set the frame around an image so it can adjust itself to the highlights and shadows.
Then deactivate the auto checkbox and you can move the frame without further adjustment.

However please be aware that this is not advised, because it can result in burned-out color values due to the highlights and shadows no longer being adjusted individually.

Kind regards,
Arne Ketelhohn.

[marcopaci]

Dear Arne,
I think this solution doesn't solve my problem.
Acting this way every time I start to scan the software adapts the highlights and the shadows to the first frame I'm gonna scan.
With the zone system I'm gonna expose the film so that to a particular exposure setting during printing corresponds a certain print value.
So using a scanner I want that a certain density value transalate in the same RGB whatever the first immage I'm gonna scan will be.
Is there any parameter to scan this way using Silverfast but using a gamma 2.2?
Thank you in advance for your attention,
Marco Paci

[LSI_Ketelhohn]

Dear Marco,

I do not quite understand what you are trying to do.
I only know the Zone System form developing B&W film.
I do not quite understand how you think this is could be applied to image digitization.

My description is supposed to make sure you get homogenous values in your scans.
Without the automatic adjustment certain values should always provide the same RGB values.

I think you are confusing analog development technics with with the digitization process.
These are two completely different processes.
What Ansel Adams is trying to provide with the zone system is a way of controlled development in a dark chamber where you can not apply control easily.
But this does not apply to the digital world where you have full and direct control of all values.

Kind regards,
Arne Ketelhohn.

[marcopaci]

Anyway is there any way to control the manual exposure of the scanner in Silverfast?
Thank you
Marco Paci

[LSI_Ketelhohn]

That depends on your scanner model.
If the scanner allows this you can do so in the preferences' special tab.
Please note that changing the exposure voids the calibrated ICC profile.

Kind regards,
Arne Ketelhohn.