DNG's in Lightroom without demosaicing

To get the most out of my E-500 Panchromat, I had to develop each image with DCRAW. That left me with an additional 16MB TIFF file for every 13MB RAW file, which is not especially space efficient really. Using the Adobe DNG Converter instead yields a nice, losslessly compressed DNG around 8MB each. After some hours of fiddling I finally managed to convince Lightroom into treating them like files from the Leica Monochrom, so that there is no demosaicing taking place anymore! Here's what you have to do:

• Take your favourite camera raw file and run it through the Adobe DNG Converter. If it's a DNG already, like from Leica or Ricoh, you can skip this step.
• Open the file with your favourite TIFF tag editor and do the following:
  – Set the value of the Tag 262 (PhotometricInterpretation) to 34892. It's supposedly 32803; if not, you're probably looking in the wrong IFD.
  – Remove the Tags 50721 (ColorMatrix1) and 50722 (ColorMatrix2) altogether. They're in the other IFD ;)
• And that's it! Now open the file in Lightroom and admire the beautiful picture.

Big question is – where to get a decent TIFF tag editor? I didn’t find one and eventually stopped searching. Since the TIFF spec’s are open and downloadable from Adobe, I finally put together a little tool for myself. Not pretty, but gets the job done.

Here's such a modified file for your personal enjoyment

 

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