[filmscanners] RE: Vuescan and multipass algorithm

["" <ake.vinberg@home.se>]

I have posted some ramblings and samples at this address:

http://www.vinberg.nu/photography/articles/multiscan/multiscan_article.htm

This is a LARGE page, lots of uncompressed images, so if you are on a modem
then please be patient.

/Åke

-----Original Message-----
From: filmscanners_owner@halftone.co.uk
[mailto:filmscanners_owner@halftone.co.uk]On Behalf Of Arthur Entlich
Sent: Saturday, May 04, 2002 5:24 AM
To: ake.vinberg@home.se
Subject: [filmscanners] Re: Vuescan and multipass algorithm


This sounds very interesting.  Can you step through the process in a bit
more detail?  Which version of Photoshop are you using, and how does one
"Apply Image in Darken Mode", what menu items and tools are you using
exactly.  I'm new to this approach.

Thanks,

Art

ake.vinberg@home.se wrote:

> I noticed the other day a peculiarity with Vuescan's multipass algorithm.
I
> scanned transparencies using a flatbed, did 16-pass scans. (Very noisy
> scanner, especially after being powered on a few hours.)
>
> The output images seem to be calculated by averaging the value in each
> pixel. The result is a smooth noise level, but no real noise elimination.
>
> As an experiment, I scanned 16 passes and did the noise elimination myself
> in Photoshop, using Apply Image in Darken mode. This mode takes the lowest
> value for each color in each pixel. The resulting image was very clean!
> Noise was completely gone, and real-life Dmax was much better. Colors did
> not seem to be affected, except for improved contrast.
>
> So: It would be great to have the option in Vuescan to choose algorithm in
> multipass scans, between Average and Minimum.
>
> Does this sound reasonable?
>
> Best regards,
>
> Åke
>


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