requesting dxo raw workflow tips

Started Jul 12, 2012 | Discussions thread
Detail Man
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Re: Detail Man
In reply to Detail Man, Aug 2, 2012

Detail Man wrote:

Have Googled the subject of ImageMagick Lanczos resizing, and it appears to be a complicated subject in itself. I may (or may not) figure this out. I have not used ImageMagick - because I am lazy about command-line stuff in my old age, and am spoiled by GUIs. You would want to make sure that it is Lanczos-3, and I am not sure that the "distort" switch is a good idea to use. Dunno. I will read a bit about this - but the ImageMagick documentation and Forum are always confusingly deep for me with my limited familarity with it. Here's the web-page for IM "switches":

http://www.imagemagick.org/script/command-line-options.php

Would suggest that you try using DxO's Bicubic to make 16-bit TIFs, and see if things get better. I know that XnView and FastStone use Lanczos-3. They are 8-bit, but that may work out for you.

I use an old version of Artizen HDR 2.86 that features 16-bit Lanczos-3. It's a weird HDR application that also has individual 16-bit editing capabilities. I just use their resizing tool only. Their newer 3.x version (renamed "Photoroom", I think) only does 8-bit processing in the trial version. They have a "Lanczos Sharper" option that was causing undesirable artifacting for me - so now I only use their standard Lanczos (which I managed to determine from their support is Lanczos-3).

In the end, the DxO 16-bit Bicubic might serve you well enough for your tastes (or the 8-bit Lanczos-3 in XnView or FastStone ). I tend to be pernsnickety, and into esoteric and (perhaps) sometimes "masochistic" rigors. Have a feeling that the ImageMagick resing may be causing you extra problems with artifacts. I would not use it unless you fully understand the command-line "switches", and how to configure it for Lanczos-3, as well as to use an appropriate "window" (which is the anti-aliasing low-pass filter that I previously described precedes re-sampling algorithms)

NikonGuyUK ,

Here is an interesting web-page that I thought of when you brought up "moire-like" artifacting:

http://bvdwolf.home.xs4all.nl/main/foto/down_sample/down_sample.htm

Unfortunately, it does not go into ImageMagick re-sampling command details - and all the ImageMagick Forum stuff that I can find is rather esoteric, flies over my head, and manages rather well to fail to clearly spell-out the command syntax for dummies every time. There must be something out there about ImageMagick that I can understand, but I never seem to be able to find it whenever I have searched. I would be interested if you find anything tangible about it !

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