What is the Adobe Digital Negative Format (DNG) and why would I want to use it?

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I hear a lot about "DNG" but what is it, and why would I want to use it?
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Photoshop FAQ, Official Rep

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Posted 9 years ago

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Jeffrey Tranberry, Sr. Product Manager, Digital Imaging

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Official Response
Here's a short list of benefits to using the Digital Negative (DNG) File format:


  1. The metadata, keywords and raw adjustments are stored in the file – along with a processed preview of the image. This makes the file portable and keeps your metadata safe and secure.

  2. DNG files are smaller than the original raw file, which will save you disk space and time in the long run.

  3. DNG is an openly specified file format which means the file format isn’t going away. If you use another raw processor that supports DNG, you don’t have to worry about compatibility or portability of your metadata.

  4. Adobe provides backwards compatibility for the latest cameras for FREE in Photoshop CS2, CS3 and CS4, as well as Lightroom 1 and 2, through the Adobe DNG Converter.



Julieanne Kost has created a video on Adobe TV outlining the benefits of DNG in your everyday workflow.

Additional Resources:


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Rob Cole

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1. I'd prefer an option for xmp sidecars too.

2. Only smaller because of reduced quality jpeg preview - correct me if I'm wrong. I believe any reduction in size due to the raw data compression algorithm is small.

3. I am a strong DNG advocate and supporter, although I don't yet use DNG myself.

4. Cool! (although I hope people upgrade to the latest Lightroom anyway!)

Cheers,
Rob
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Gene McCullagh

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To expand on Jeff's first item... Having this data stored within the DNG removes the need for those XMP sidecar files. Many users I've talked to get tripped up when they move the raw files but forget about the XMP files. DNG makes this a thing of the past. It's worth the extra step to convert IMHO!
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TK

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Can someone summarise what is lost when converting to the DNG format? I understand that Pentax K20D RAW files contain data for the masked pixels on the sensor and that this information is lost in a DNG conversion. The vast majority will never miss the lost data, but I wonder what other differences between the original RAW data and the DNG representation there might be. Are black levels changed, for example?

N.B., I convert all my RAW files to DNG because of the benefits 1.-3. listed by Jeffrey.
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Rob Cole

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The question of why you would want to use DNG has been answered. Just be aware that not all other software manufacturer's products will be able to read the converted DNGs. The most obvious being the camera manufacturer's software, but there are others. My advice: convert if you want, but save your original RAWs!!!
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Jeffrey Tranberry, Sr. Product Manager, Digital Imaging

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That's a good point, Rob, and points to a larger question about workflow, back-up and archiving. I know a ton of photographers who use that approach, archiving the original raw files, and using DNG as the working negative. Peter Krogh's DAM Book talks more about this overall strategy.
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Rob Cole

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Yup. I confess, I still occasionally process some photos with Nx2, and I like keeping my options open. But, Lr3 has gotten so good that I rarely use Nx2 for raw conversion now (or anything else).

PS - Another advantage of DNG that has not been mentioned:

- The ability to store DNG color profiles (which can be read in Lightroom).
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Jeffrey Tranberry, Sr. Product Manager, Digital Imaging

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Cool. Good point. Thanks for adding that.
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Baldo Faieta

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This reply was created from a merged topic originally titled
What is Adobe Digital Negative Format (DNF)?.
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Photographe

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Best of all, if you ever decide to go back to RAW (and you've kept those RAW files somewhere), you'll become an expert in SQL!

http://feedback.photoshop.com/photosh...
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Rob Cole

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Good point Photographe. To summarize: unless Adobe adds a reversion feature, converting from DNG back to RAW (should you need or want to), is a multi-step procedure involving either loss of edit history, virtual copies, stacking, and collection affiliation..., or extensive manipulation of lrcat database via SQL, in short:

1 - Round up the original raws from backup and place in same folder as DNGs.
2 - Rename if necessary to match.
3 - Save XMP (to DNG)
4 - Extract XMP using ExifTool (to sidecar)
5 - Delete the DNGs
6 - Resync the folders (losing some stuff)
or use SQL like Photographe did for lossless reversion, instead of steps 3,4, & 6.

(backup your catalog first - blah,blah,blah,...)

Oops - forgot to mention: I've heard John Beardy's Syncomatic plugin can help too (for transferring metadata and settings, instead of going through xmp) - maybe consider that option.

(see link above for more info)
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Jill Lynch

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So every adjustment (Including masks) you have made from lightroom is saved in the DNG file!

Why do I have all these dngs with sidecar files in my directories!? Are sidecars only neccessary for raw files? If my catalog file was deleted but everything was saved as a dng -- the adjustments would be in the dngs -- and I wouldn't lose anything right?
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Jeffrey Tranberry, Sr. Product Manager, Digital Imaging

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Could the Sidecars be remnants from prior to the files being converted to DNG?
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Rob Cole

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Lightroom will never write DNG sidecars, but it will read them. Some other apps (e.g. Bridge/Photoshop) will only write them if DNG is read-only. But when you convert to DNG, the xmp sidecars associated with the original raws will not be deleted, unless you elect to delete original raws upon conversion.
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Rob Cole

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Jill - not *everything* is in xmp. You won't lose develop settings nor critical metadata like keywords and ratings, but you will lose edit history, virtual copies, stacking, collection affiliation, and whatever else is only stored in the catalog.