To DNG or Not to DNG? That is the question!

All you NAPP members out there, check the Lightroom section of your latest Photoshop User magazine (March 2009) for MY article on DNG!

For those of you who aren’t NAPP members, you’ll want to sign up now!!!

In the meantime, here’s the main bullets points directly from Adobe Lightroom 2 – The Missing FAQ

File size
DNG files are generally 10-40% smaller than their original proprietary format, depending partly on the size of the preview that you choose to embed.

XMP Sidecars
Proprietary raw formats have their XMP data stored as a sidecar XMP file, whereas DNG files have that information embedded within the single DNG file.  The question is, do you find sidecar files a pro or con?

Long Term Storage
The DNG format is openly documented, which means that it should be supported indefinitely, whereas proprietary formats such as CR2, NEF, RAF etc. are not openly documented.  Will you be able to find a raw converter in 20 years time that will convert a proprietary format when that camera model is ancient history?

Manufacturer’s Software
Most manufacturer’s own software will not read a DNG file, only their own proprietary formats.  Do you ever need to open a file in the manufacturer’s own software?  If so, you’d want to embed the proprietary raw file – it can be extracted use the DNG Converter tool, however it does negate the file size benefits.

MakerNotes
While there is DNG support for MakerNotes, some manufacturers don’t stick to the rules, and therefore MakerNotes embedded in an undocumented format can’t always be carried over to the DNG file, however if you’re not sure what the MakerNotes are, you probably won’t miss them.

Check the Photoshop User article for lots more pros, cons and how to’s.

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February 1, 2009 | Victoria Bampton
This entry was posted in 1 - Library, Book Excerpts, LR 1, LR 2 and tagged , , , , , , , , . Bookmark the permalink.
  • http://lightroomers.com Rob Sylvan

    Can’t wait to see it! :-)

    [Thanks Rob! It's already available on the Zinio download, so hopefully the printed ones will arrive soon too! - VB]

  • Pat

    Read your article in the latest NAPP magazine and found it very informative. What I have not seen written about to any extent is saving the DNG files after precessing in LR. Can you address the full finish to the LR work flow. I know images can be printed, exported, saved as various files but I seem to end up with a lot of images that I’ve spent time editing but right now don’t need to export or print. They are DNG files and the adjustments are stored in the catalog. Even though I back up my catalong on another drive, it seems I’m missing something to finish off this process and it doesn’t seem secure to me to leave them at this stage. It seems I should be saving these images as a completed master in some format so I can resize, sharpen and output as I need. Does this saving process have to be done image by image or can it be done in groups? Thanks for addressing this.

    [Hi Pat! As you noted, all of your changes that you do in Lightroom are stored in Lightroom's catalog, and they should be quite safe there as long as you follow sensible backup plans. That said, you can update the DNG files themselves with that information, without creating another file or affecting the raw data. To do so, select the files in Grid view, and go to Metadata menu > Update DNG Metadata & Preview. All of your settings will be written out to the file itself, and the preview updated, as well as still being stored in the catalog. Let me know if you have any more questions. - VB]

  • TheShape

    Very interesting. I am going to have to delve into this a little bit. Thanks for all the info.

  • Phil

    Hello,

    I am having troubles when exporting to DNG via LR2. The files I am editing and attempting to export are .CR2 files.

    My issue is that all of the exported files do not display any of the changes made to them while in LR2. I have done as you suggested to Pat above ie Update DNG Metadata & Preview. Any suggestions would be much appreciated.

    Regards

    Phil

    [Phil, that sounds a bit odd. Are you selecting DNG as the file type in the Export dialog? If it's still not working, drop by http://www.lightroomforums.net and we'll get you sorted out in no time. - VB]

  • Steve S

    Does anyone know of a DNG plugin for MS Internet Explorer that would allow me to see thumbnails in IE? This is available for NEF files.

    [For Internet Explorer? You don't mean Windows Explorer? - VB]

  • Huntley Paton

    I found this very useful, thank you. My question concerns file size. You wrote that DNG files tend to be significantly smaller than their RAW sources (if I read you correctly) but the opposite seems to be happening to me. Here’s my workflow: I import RAW cr2 files into Lightoom 3 beta and then do processing work on them in DxO Optics Pro v5.3.7 for Mac. The RAW file that goes into Lightroom is usually around 23-25mb in size …. when I process it in DxO and import back into Lightroom, however, I now have a DNG file about 70mb big … that’s just way too big for my hard-drive budget. I suppose I can change setting either in DxO or Lightroom to save a smaller version of the file, but does that mean I am saving at a lower quality? I don’t want to do that either! (that’s why I’m trying to get away from jpegs.) Any advice much appreciated.

    [Standard DNG of raw data, yes, are smaller. There's a different type however - linear DNG - which are demosaiced data, which could be described as being half way between a true raw file and a TIFF. Those are the kind of DNG that DXO produce as DXO has to demosaic the data in order to apply its settings, and they are much much larger, as you've noted. There's no easy way round that I'm afraid, when you're going to another program.- VB]

  • Huntley Paton

    Thank you very much for that answer — looks like I will have to stick with JPEGs only as output when doing RAW processing in DXO. Sounds like it would still be a good idea to convert all my raw files to DNG within Lightroom, though. Think I saw an explanation somewhere about how to do that in batch.

    [Yeah, sounds like a plan. The raw files - select them in Grid view and you'll find the Convert to DNG under the Library menu. Just double check that DXO will be able to read those DNG files as I haven't checked that lately. - VB]

  • Huntley Paton

    Will do! And will report back if I learn anything interesting — or disturbing.

    Most grateful for your help!