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I accidentally shot in 12 bit color instead of 14 bit, and now, no matter what Linux program I use, the .NEFs are green and underexposed.

As I said, I'm using Linux, and my camera is a Nikon D5300.

How can I automatically adjust the colors and exposure of all my files to be make them look the way they were intended?

Edit: Here's a link to one of the raw photoes: https://www.dropbox.com/s/ylhyob45wf9cq7d/DSC_0440.NEF?dl=0

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    The fact that you shot it in 12 bit instead of 14 bit won't matter mush. Can you provide a photo as an example? Is the image green as a result of incorrect white balance or is it a raw interpretation issue? What program are you using? When you say underexposed do you mean that you shot them underexposed or that the histogram looked fine in camera and then got changed when opened in the raw converter?
    – Hugo
    Oct 20, 2015 at 15:50
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    @Hugo — this is actually a common problem. See for example rawtherapee.com/forum/viewtopic.php?f=3&t=5406
    – mattdm
    Oct 20, 2015 at 15:54
  • So in this specific case the fact that they were in 12 bit actually mattered! What I intended by sayng it didn't was that underexposure can be corrected quite well even in 12 bit. But in this case it leads to problems. Anyhow the images are fine at least. As long as you edit them with another converter or wait till the interpretation error is fixed.
    – Hugo
    Oct 20, 2015 at 16:01
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    For information: the issue is about software (see link) and not about the bits themselves. I used 12 bit for years and the difference with 14 bits is barely visible. You mention D5300, check here: diyphotography.net/… Also, again for info only: if the camera has about 13 bits of original dynamic range (D5300 for example sensorgen.info/NikonD5300.html) and you shoot at 400 ISO, you already have less than 12 bit in the input data. 14 bits are not needed beyond ISO 200-400. Surprise!
    – FarO
    Oct 20, 2015 at 17:09
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    Use a different raw converter. It is software bug.
    – Iliah Borg
    Oct 21, 2015 at 1:22

1 Answer 1

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As written in the comments (see http://rawtherapee.com/forum/viewtopic.php?f=3&t=5406) the issue is not intrinsic to 12 bits, but it is caused by a wrong interpretation of the RAW data by dcraw (the common RAW decoder used in most Linux software). The link above provides a temporary solution (set black point to -450) while waiting for an updated dcraw (you may try to compile the latest version, too). Thumbnails won't be correctly displayed anyway.

However, don't jump immediately to 14 bits unless you know you need them: I used 12 bit for years and the difference with 14 bits is barely visible.

Not only is barely visible, often the different is actually nothing: if the camera has about 13 bits of original dynamic range (the D5300 for example http://sensorgen.info/NikonD5300.html) and you shoot at 400 ISO, you already have less than 12 bit in the input data. 14 bits are not needed beyond ISO 200-400 ISO. Surprise!

If you use ISO of 100-200, you can still check here for real examples to understand what you actually gain for those two sensitivities: http://www.diyphotography.net/12bit-vs-14bit-raw-and-compressed-vs-uncompressed-does-it-matter/

You may want to check what is the file size difference for photos with extreme dynamic range at 100, 400, 1600 ISO. As for extreme dynamic range, stay inside a room of your apartment, one with some dark shadows, while at the same time you have a sunny landscape (buildings, sky, and so on) visible through the window. This should offer you more than 14 bits of dynamic range. Set the camera to Auto, check the exposure, then set it to manual with that exposure. Use a tripod, take one shot at each of the sensitivities I listed, then change bit depth, take again the same three shots. Download the files, compare the size and check if the additional space 14 bits require is justified by the additional highlights and shadows you can recover.

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  • It works! Is there a way I can do this to all my raw files?
    – A.J. Ruckman
    Oct 21, 2015 at 15:27
  • You don't mention which software you use, you should look how to script the operation of that software...
    – FarO
    Oct 22, 2015 at 12:42

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