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Help with processing files

  • gcsf

    gcsf - 2012-10-26

    Hi, I'm attempting to use Cornerfix on DNGs captured by my phone's camera (Nokia N900, using FCamera). I've followed the guide, read the docs, and created lens profiles. Results between the CF-preview and the CF-processed file are drastically different, and I'd like to narrow the gap between them.

    Please see

    Vignetting is better, but the CF-processed image color is very different from the CF-preview.

    1: the source image (in CF)
    2: CF-preview
    3: CF-processed image, opened with IrfanView. All color and monitor profiling is disabled in IrfV. I also see the same results using Scarab Darkroom and Raw Therapee.

    Using XP, SP3, with latest versions of .Net installed, and intentionally using an 'extreme' profile for testing (I have created better, this profile shows off what I'm trying to resolve).

    I have tried various sequences of opening and processing the files (open img -> open profile -> apply; open profile-> open img -> apply; etc), with the same results each time. In the CF 'Image correction options", Luminance and Chroma are set to 1.

    I'm not sure if the color difference is related to IrfanView, the CF processing, the OS, etc. I don't know where to go from here, and am seeking insight into next steps.

  • Sandy McGuffog

    Sandy McGuffog - 2012-10-26

    Well, the first issue is that CornerFix is color managed, so if color and monitor profiling is disabled in IrfanView, then the results on screen will not be comparable.

    What I'd suggest doing is firstly to enable color management in all your apps - without that, you're comparing apples to oranges.

    Secondly, open the original and CF converted DNG in ifRanView alongside each other, and see if there's a difference.

    If there's still a difference, then try the same test with one of the Adobe products, either Lighroom and PhotoShop, and see whether there's difference between the two DNGs.


  • gcsf

    gcsf - 2012-10-31

    thanks for your help. I appreciate the depth of your answer. I wasn't explicit  enough in my question, I had actually spent many hours tinkering with color profile management  in IrfV before posting, comparing, etc, and this image in this post was the closest to the Cf-preview image. I understand the apples-to-oranges problem, just couldn't figure out where this might be breaking down. Your point got me to tinker around more, and I found a solution.

    As suggested, I re-applied color mgmt profiles to IrFanView, but color data still not correct applied. They did shift, but still did not resemble the preview or original image.  I'm still not sure why (I suspect all some of the data in the DNG is not correctly read), and frankly don't care too much, so I moved on.

    The Gimp, using the uFRaw, plugin, works correctly. the profiles are applied to both opened and  and exported images,  with pngs, tiff, jpg exports tested (the DNG files and exported pngs/jpgs/tiffs look 'correct' across multiple computers). This works~

    My next step is working with batches in both CornerFix and the Gimp.

    Thanks again for un-sticking my stubborn mind :)


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