Thanks for taking the time and trouble to run this test and to post the results.
To me it's clear that VueScan's 7.2.3+ grain-reduction filter is a substantial
improvement over 7.1.23 and 7.1.25
Thanks, Ed, for the improvement.
Maris
----- Original Message -----
From: "Bob Shomler" <bob@shomler.com>
To: <filmscanners@halftone.co.uk>
Sent: Monday, November 12, 2001 6:13 PM
Subject: filmscanners: Vuescan 7.2.3+ Filter|Grain reduction
| Someone recently asked if there was any discernible difference among the
|low-medium-high settings with Ed's improved grain reduction filter in vuescan
|7.2.3. I thought I'd try some small comparisons from a negative scan, a small
|crop of sky and snow from a near-end-of daylight scene -- sky being a common
|area where grain aliasing is noticeable and grain a reduction filter can
|assist with image quality.
|
| I think differences are noticeable. File sizes of almost same 200x200 pixel
|crop are different: 28, 25, 23 and 21 KB for none, low, medium and high grain
|filter setting (decreasing file size indicating a reduction in detail from the
|filter action).
|
| I also included the same crop processed by vuescan 7.1.23 and 7.1.25 (these
|exhibit color differences too). The negative was scanned on a LS-30 at full
|res (2700) using white balance color and IR clean. Six files are at
|
| www.shomler.com/vuescan/
|
| v7203n.jpg, v7203l.jpg, v7203m.jpg, v7203h.jpg, v7125h.jpg and v7123h.jpg are
|approximately the same crop using, respectively vuescan grain reduction
|filters 7.2.3 none. 7.2.3 low, 7.2.3 medium, 7.2.3 high, 7.1.25 high and
|7.1.23 high. Scan was with IR clean on. There are some color differences
|between 7.1.23, 7.1.25 and 7.2.3. Scans are 48-bit mode, reduced to 24bit in
|photoshop 6.0.1. Jpeg is from photoshop, compression maximum quality/12,
|color space AdobeRGB.
|
| Complete image (September sunset on Mt. Shasta, California) may be seen at
|
| www.shomler.com/other/0011329.jpg
|
| Crop is from upper right quadrant.
|
|
| --
| Bob Shomler
|
|
