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Do I really need to prescan if I post-process?

PostPosted: Tue Sep 23, 2014 12:22 am
by sined.drahcir
Hi!

New here. Just wondering what exactly the prescan does and whether I need it if I post process anyway. All I do right now is turn CCR, Auto Demask and Negafix on to get me on a good start, then make sure there's no clipping, then scan the full copy. Is there any way I can use CCR, Auto Demask and Negafix, and still avoid clipping without a prescan?

I guess the meat of my question is whether the settings (Negafix etx..) of the current prescan are blindly applied to the next scan or whether the settings are readjusted every time the scan button is pressed (without having necessarily prescanned).

Best wishes and thanks for all the help on this forum!

Re: Do I really need to prescan if I post-process?

PostPosted: Tue Sep 23, 2014 2:36 pm
by LSI_Ketelhohn
Dear customer,

The Prescan is necessary to set up the highlights/shadows values (e.g. using the Auto CCR).
This must be done on the image's data before the final scan is done.

Kind regards,
Arne Ketelhohn.

Re: Do I really need to prescan if I post-process?

PostPosted: Tue Sep 23, 2014 3:30 pm
by sined.drahcir
Thanks for the quick reply!

So if I were to keep Negafix on with the auto demask function (but without auto CCR), and use the histogram function with blacks set to 0 and whites to 255, I would be able to keep all information for post-processing with Lightroom, without having to prescan?

Re: Do I really need to prescan if I post-process?

PostPosted: Tue Sep 23, 2014 4:56 pm
by LSI_Ketelhohn
No that way you would loose quality/image information (dynamic range) during the rendering of the image.
The highlights and shadows should be set in SilverFast before the scan is performed.

Kind regards,
Arne Ketelhohn.