Re: 8 bits versus 16 bits edit
Re: 8 bits versus 16 bits edit
- Subject: Re: 8 bits versus 16 bits edit
- From: Paul Schilliger <email@hidden>
- Date: Tue, 08 Jan 2002 19:43:23 +0100
Stephen,
>
Stephen Marsh wrote:
>
>
>Paul, there are two common scanning workflows:
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>* Edit in scanner for as many edits as possible, this will be performed
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>in high bit mode taking advantage of hardware and software in the
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>scanner where possible. After internal processing from higher bits per
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>channel, a 8 bpc image is the result. Some software allows the high bit
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>file to be saved, instead of reducing it down to a regular bit level.
This is what I am doing now. Working with input and output profiles allows me to use the auto endpoints and contrast curves of
the scanner without drifting from the original slide's colors. The scans need a little correcting in PS for contrast and
density, sometimes for removing a cast that is too present in the slide, but this is normally made by simply adding a curves
layer.
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>
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>* Lock down settings or 'dumb down' the scanner with fixed settings and
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>scan every file in high bit mode with the correct custom scanner
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>profile. An image editor is used in lieu of scanner software to tone and
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>colour correct the file in high bit mode. This file or a dupe can then
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>be reduced to 8 bpc mode for a more regular workflow and output.
The scans I have made earlier were made that way, but output in 8 bit p.c. as there was no high bit option with this scanner.
This was the only way to preserve the colors of the slide in non-ICC mode. The raw scans are dark and linear, but by adding a
curve layer, they usually come all right, although certainly not as good as with the first method explained. I think I will
rescan some of the old scans in ICC mode, especially the dark ones, to improve details and tonal values in the shadows.
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>In my high bit workflow tests, the only visual difference betweem the
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>two was edits in high bit looked as if it had a 0.2 pix gaussian blur
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>applied (it looked almost imperceptably softer on a hi res file). This
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>was monitor, on output there was no apparent difference (halftone and
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>stochastic output tend to average out small detail, although contone
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>output may differ).
Thanks for the links to interesting resources.
Banding has not been too much of a problem for me so far, except in a couple of blue skies but there, the images were edited for
the web from files that had already supported a number of transforms, and not from the original scans
Thanks again!
Paul
email@hidden