Archived posting to the Leica Users Group, 1999/10/10

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Subject: Re: [Leica] digital printing - scan negs or prints?
From: "Anthony Atkielski" <anthony@atkielski.com>
Date: Sun, 10 Oct 1999 23:22:31 +0200

From: Simon Pulman-Jones <spulmanjones@lbs.ac.uk>
Sent: Sunday, October 10, 1999 15:07
Subject: RE: [Leica] digital printing - scan negs or prints?


> Maybe at this stage it would be better for me to use a
> (relatively cheap) flat bed to scan prints and forget
> about trying to decide between 2700 dpi or 4000
> dpi film scanners.

No.  If you want quality, you must scan film directly.  The fewer generations
you have, the better the final result will be.

> What are the quality considerations between scanning
> prints and negs/trans?

There are far fewer variables and things that can go wrong when you scan film
directly.  Furthemore, scanning film directly keeps more of the workflow in the
digital domain, where degradation cannot occur, whereas scanning prints places
too much dependence on the analog domain, where every operation degrades image
quality to some extent.

> I was surprised when I saw the article arguing in favour
> of using 7x5 inch print scans for A3 inkjet prints because
> I had assumed that the dynamic range from a print scan would be
> significantly inferior to a film scan.

Your assumption is correct.  Reflected light provides a much smaller dynamic
range than transmitted light or direct illumination (as on a monitor).  It is
_extraordinarily_ difficult to produce a print that can reflect between exactly
0% and exactly 100% of incident light, especially in color, and it is difficult
to illuminate it brightly enough to make the range between 0 and 100 percent
reflectance large in terms of actual luminance.

You are way better off scanning film.  The difference between scanning film and
scanning prints is like night and day.

  -- Anthony