Lightroom Tips

The DNG Follow Up Post

First off, thanks for all of the conversation in the comments on the DNG article the other day. I wanted to post a follow up to give some more thoughts and answer a few questions?

For starters, I have to say there were more DNGers than I thought. I didn’t go through and count each one but it felt like a 40/60 split (DNG/Not DNG). Based on my experience at workshops and seminars, that’s more pro-DNG than what I’ve been used to. And that’s a good thing. Don’t get me wrong. Even though my post talked about some reasons people don’t use DNG and I admitted that I don’t convert to DNG, doesn’t mean I’m not a fan of it. More on this at the end of this article though. Let’s start the Q&A:

Q. Was that Tom Hogarty I saw commenting? Isn’t he the Lightroom product manager for Adobe?

A. Yep, but he’s also the DNG product manager. When it comes to DNG Tom is the man. He wrote a pretty detailed response to each of my reasons that’s worth reading. Just look through the comments from the original post and do a search for Tom’s last name and you’ll find it. Tom also wrote about this on his blog a while back. You can read more here.

Q. Matt, you wrote “And Lightroom doesn’t automatically update the DNG file if you make changes. You still manually need to go to the Photo menu to save the settings.” Isn’t there a setting in Lightroom to automatically save your changes?

A. This question came up quite a bit. The easy answer is yes, there is a setting that will let you write your changes automatically to the file. Its in the Catalog Settings (Lightroom menu on Mac, and Edit menu on PC). But this option is off by default. So if you’re editing DNG files in Lightroom don’t be fooled into thinking that your changes are being saved automatically. Just like raw files, you either need to turn this option on or manually save changes in the Photo menu (Cmd/Ctrl – S).

Q. I understand the “Convert to DNG because you never know what happens 50 year from now” argument, but somehow don’t buy it.  My understanding is that Adobe is the company that maintains DNG: What if they are no longer around?

A. Good point. All the more reason why DNG should become an industry standard. Don’t quote me on this, but I’m pretty sure that Adobe would submit the DNG format to become an industry standard. If this happened they’d probably lose significant control over what happens with the format. Lots of other industries use standards (Pharmaceuticals for example). Without a common document exchanging standard of some sort, they’d face chaos. Imagine if one company changed their documents. Every single company that they dealt with would have to adapt and change their software to account for the change. So by having a standard, everyone’s life is better. Same goes for raw formats. If there’s one standard that the raw files have to follow (say, DNG) then everyone’s life becomes easier.

So if DNG became an industry standard, it would live on even if the company that created did not.

Q. Does DNG work with Capture NX2?

A. Nope, Capture NX2 doesn’t work with DNG. I’m not sure this is a good reason not to use DNG though. Here’s the thing. How many programs do you really need to edit your photos? You’re reading this blog which probably means you’re a Lightroom user. Then use it. You paid for it. Things like D-lighting and picture controls and things like that are all in Lightroom and Photoshop in some way, shape or form.

One more thing. Please don’t turn this into a Capture NX2 debate in the comments. If you use it and you’re happy, then go for it 🙂

Q. OK Matt, DNG seems like a no-brainer. Any reasons not to use it don’t really seem to apply to you. So what gives? Why won’t you start using DNG?

A. Good question. One of the folks who wrote a comment made a prediction that I’d be converting to DNG before long and I think that’s a good bet. I’ll keep you posted if/when it happens.

Thanks again for all of your feedback.



  1. Jesse Morgan 22 September, 2011 at 22:57 Reply

    I tried to work with DNG, using Lightroom 3… however my changes never seem to get saved. Doesn’t matter if I turn on the auto-save meta data at the catalog level or manually save it, nothing is saved. Very frustrating, don’t know if this is a bug or what.

    Has anyone had issues like this?

  2. Carol Straubel 24 June, 2010 at 12:04 Reply

    Started shooting raw and using LR2 last fall so am a novice. Everything I read said to convert to DNG so did at every import. Just upgraded to LR3 and made an error on my first import and both the raw image and Dng images were side by side in my catalogue. As I went through cleaning up I realized that very often there was a very visible color difference between the two versions and I preferred the raw version. I use a Sony a850. What is with the difference?

  3. John Wadleigh 28 April, 2010 at 17:06 Reply

    Again, my main question and concern with DNG is whether it truly still represents a “raw” file type. What I mean is, when photo competitions request your original raw photo as proof of how much edits you made or did not make.. will the DNG file be sufficient? Can someone create a DNG file that has had serious edits to it? YES! In Lightroom for example you can make a ton of changes to a DNG file and the changes are saved in the DNG file itself. So sending that to the competition will not work because they cannot themselves determine if that is the original or not. With a RAW file from the camera, the edits are saved in the XMP, so just send the competition the RAW file and not the XMP. Done.

    I got bit on this recently with a competition and it was quite frustrating! Now I have returned back to only using RAW files.

    It is unfortunate because I really love the benefits of DNG, but its not worth the risk again of possibly not being able to submit my photos.

  4. Scilence 13 April, 2010 at 00:43 Reply

    DNG sucks. CR2 sucks. NEF sucks. I am an expert in image and video file formats and all I can say about those three formats is – the more time you invest researching and converting them and the more technical details you understand – the more frustrated you will become. Also there is no light at the end of this tunnel!

    My recommendation is:
    Shoot RAW
    Use an X-rite color chart to build a proper color profile in Capture One
    De-fringe and and de-noise in Capture One
    Debayer in Capture One (Compressing the dynamic range)
    Save as 16Bit Tiff
    Load 16Bit Tiff in Dxo Optics Pro
    Auto correct vignettes and lens distortions in Dxo based on their lens database
    Save as 16 Bit Tiff

    Open Photoshop CS3/4/5
    Convert the 16Bit Tiff into an OpenEXR 16 or 32 bpc (Lossless)
    (~80 MB on a 5DMkII)

    Convert the 16Bit Tiff into a 16 Bit Jpeg2000 (Jp2) (Almost lossless)
    (~ 6-20 MB on a 5DMkII)

    DELETE Tiffs and RAWs

    Save EXRs or JP2s on a local HD + on a NAS + on BluRay(And send those to your mum in case someone spills beer on all your HDs

      • Scilence 13 April, 2010 at 20:36 Reply


        Looking at my own list makes me sad…
        What have I become?! A tech nerd! A file format geek! A slave to compression algorithms and bit depths! A sad shadow of an artist who actually just wants to shoot photos but got cought up in the massive ropes and insane complexity of a gigantic spiderweb of ill designed technology…

        I feel sorry for myself. I feel sorry for everyone who just wants to be creative.


  5. eddie 20 January, 2010 at 01:05 Reply

    Well, I’m eddie.
    I’m the person who originally asked the question about DNG. I was pretty much ignored…well I did get one response. I figured I’d go elsewhere to find answers. I was going through my bookmarks and came back here. Jeesh, so now you start to talk about it. I figure I have some reading here to do. I better get busy.

  6. Victor Cajiao 16 January, 2010 at 12:39 Reply

    So my question is this. I have my LR catalog file in dropbox so I can use the same one for my desktop and laptop Macs. If I use dng, then that meta data would not be in the side car but inside the pictures , therefore keeping my desktop and laptop in sync might be harder. Am I right about this? If not please school me.

  7. CityShooter 15 January, 2010 at 22:51 Reply

    Hi! A common format would be wonderful.

    The side car files can be very helpful. If you look at the sidecar files in finder/explorer you can see when you made a change to the file. This can be helpful in keeping track of your workflow. It also makes it easy to go all the way back to the original – just delete the xmp file.

    It is sometimes helpful to use the manufacturer’s proprietary software – to see which sensors were being used for autofocus, which focus mode was being used, etc. If you normally shoot raw, you can use the manufacturer’s software to switch the various settings for processing to see how the in camera settings would create a jpg. The raw + jpg workflow is helpful if you need to spit out jpgs on site – this at least gives you some level of processing. (I prefer not to do this since the processed stuff appears on the lcd, but sometimes it is worth it.) This can great learning tool – just check the box and your photo is black and white!

    With the wonderful batch capabilities available, you can wait to convert to dng until the danger of loss of future support appears. You don’t need to anticipate it and lose the options.

  8. Shawn 14 January, 2010 at 20:31 Reply

    I am surprised that Canon hasn’t adopted the DNG idea already. After all, they have never had an original idea before.

  9. Jim Lewis 14 January, 2010 at 16:26 Reply

    Another advantage of DNG is that others can write to it. Ed Hamrick uses it in his VueScan program so that a scan is saved in the DNG format and can be endlessly toyed with at a later date without rescanning.

  10. Marshalus 14 January, 2010 at 14:58 Reply

    I converted all my .NEF to .DNG files a couple years ago, then dumped the .NEF files, and now I just convert on import from the CF cards. Then I back them up “for ever and ever.” The 20% reduction in file size was great until a couple weeks later when I filled it right back up again.

    I think it’ll be a few more years until DNG is fully mainstream for everyones workflow, and probably another decade before companies like Canon and Nikon create the DNG file right in the camera, instead of their current formats.

  11. Michael 14 January, 2010 at 08:31 Reply

    Q. Matt, you wrote “And Lightroom doesn’t automatically update the DNG file if you make changes. You still manually need to go to the Photo menu to save the settings.” Isn’t there a setting in Lightroom to automatically save your changes?

    Matt, I think there’s been some serious confusion here and a lot of people, including myself, don’t really understand your answer. Perhaps an idea would be to do a post about this topic if you haven’t done so before.

  12. James Fitzell 13 January, 2010 at 21:01 Reply

    While I agree that DNG is a good standard and might be useful in the long term, I have yet to see anyone provide a compelling reason to start using it right now.

    To explain, using the following benefits:
    “RAW compatibility” – I have doubts that Canon/Nikon etc will dump their RAW support anytime soon, or Adobe stop supporting the older formats, but even if this happens I’ll simply convert to DNG at that point… there’s no reason to do this now.
    “Program compatibility” – Sure there may be multiple programs that start supporting DNG files, but even if they support DNG and not my RAW file anymore, they don’t support the Lightroom specific changes to my files (the XMP data) so I’m still stuck.

    To my mind the bigger issue (in my case atleast) is that right now I can backup all my files and all my changes to another drive, and as changes occur I’m syncing across XMP data every time it changes… switch to DNG and suddenly I need to sync across a whole file every time I change one develop setting. I also backup the LR database but I will ALWAYS store a copy of my XMP changes with the file because I want the added protection.

    So with CR2+XMP I copy 15MB once and 1KB many many times. With DNG I copy ~15MB many many times, that’s not progress for me.

  13. Leo 13 January, 2010 at 13:39 Reply

    hey, I hope this question doesn’t get lost among the other comments, but maby you or people who read the blog can help me on this:

    – How do you use Lightroom to turn it into a photo viewer at a non proffessional, not even amateur level. I mean, it’s great for processing and cataloguing and printing and stuff…but when you want your friends/family/etc. just take a look at the 1500 photos of your last trip, it’s a little messy, specially with all the previewing issue and/or if your catalogue runs a little slow. Do you use it like that or use something else?


  14. Dave Stevens 13 January, 2010 at 12:13 Reply

    Good posts on whether to DNG or not. But why is everyone so concerned about 50 years from now? How many images are created each day? Why would someone 50 years from now spend time in looking at your images when newer, fresher, edgier images are available? Will the media that you saved your images on be viable? Will there be computers that will even open them? The best solution is to follow the guiding principle used by the Getty Museum in LA, preserve the printed image. It is the printed image that truly represents the artist’s, photographer’s, journalist’s intent, interpretation and vision. The printed image does not require any software or hardware to be viewed and appreciated. My answer to this question is to print, share more often and worry less about 50 years from now. Print your images the best way possible, use archival materials and share the images, give them to family, friends, whomever. Look at all the masters before digital imaging. They shared their images with the public. Their printed images represented their vision as to how they interpreted the subject. My answer to this question – go print.

  15. RON 13 January, 2010 at 01:12 Reply


  16. Frank 12 January, 2010 at 19:09 Reply

    I have been using DNG for a year and so far see only plusses, especially the 15% smaller image size. I import my CR2 file from my Canon 5DM2, put the images in its folder, import them into Lightroom and then convert them to DNG. If Adobe goes out of business years from now, I am sure there will be some kind of mechanism to convert them to whatever standard then exists. This is one of the many “what if” questions of life that I just don’t lose sleep over.

  17. RON 12 January, 2010 at 13:25 Reply

    I actually make a copy of my raws ( only temp ) and convert them to DNG and then burn both the raws and DNG to dvd so i keep the best of both worlds just in case. Thats my answer to it all.

  18. Barry Pearson 12 January, 2010 at 12:58 Reply

    “Peter” (January 11, 2010 at 7:12 am) talked about convertion to linear DNG being useful in some cases, but being unable to predict whether it would be needed in future.

    The answer is to convert to raw DNG now, and then convert those to linear DNG in future of necessary. (This is possible at the moment, for example by running DNGs through the DNG Converter with a different option set. Obviously the DNG Converter can read DNG files!)

  19. Donald 12 January, 2010 at 09:45 Reply

    So, I’m interested in DNG now. What is the best way to convert my RAW images (from Canon 5D and Panasonic Lumix LX3) AND keeping my LR2 library?

  20. John Birch 12 January, 2010 at 02:07 Reply

    I’ve read Matt’s postings and all these comments and those of Tom Hogarty with great interest. But like Matt, I’m still sat on the fence about converting my Canon CR2 RAW files to DNG. In principal it sounds absolutely the way to go. What could be better than a universal format, adopted by all. However, that’s just the caveat isn’t it, it’s not adopted by all and until the major players like Canon and Nikon start supporting DNG us consumers will still be just that tiny bit wary that we are going to loose something from our original RAW files by converting.

    At present, although I’d like to commit to DNG, I just couldn’t bring myself to ditch my original CR2 files, hence the space saving benefit of a smaller DNG than CR2 is neither here nor there, in fact I’m going to end up doing twice as many backups and at least 4 times as much disk space (I always keep 2 backups). Disk space is cheap you say, but the hassle of doing all this soon mounts up and it’s another dull step in the workflow which takes precious time away from the actual good stuff of working with your pictures.

    In Canon DPP I can view my focus points and see where the camera focused. I can’t do that in Lightroom or any other software I know (correct me if I’m wrong). It’s not a particular facility I use that often, if at all, however it just demonstrates that there seems to be hidden proprietary information within a maker’s RAW file that we stand to loose by converting to DNG. It may not be particularly important information, but I may not find that out till it’s too late.

    I agree with the DNG format in principal and would like to commit to conversion as I can clearly see the benefits. However, I don’t think the question is, should we convert on should we not convert, but rather how to we, the users, can get the point across to the people at Canon and Nikon that consumers want DNG support built in to their cameras and software. Until these two giants within the industry adopt DNG there will always be consumers like me who are slightly wary of dispensing with our original RAW Files.

    Matt, you have much close ties with the industry, why not present some sort of vote/poll on the site here; maybe, just maybe, Canon and Nikon may take note then? How else are we to persuade them?

    One last point, I realise Adobe freely publish the DNG open standard so anyone can adopt DNG, but do Adobe approach companies like Canon and Nikon and try to persuade them to use DNG? If not perhaps they should. It would be interesting to know.

  21. Bryan 11 January, 2010 at 22:45 Reply

    Interesting topic. Seems to be generating more questions all the time. Adobe needs to step up and write a clear concise white paper on DNG without the corporate bias.

    DNG is a published standard as pointed out. DNG like other RAW formats is not universally supported by editing software. There appear to be advantages but I have not used it. I think there is no need to. Long-term FUD about camera RAW format support is just that, and applies equally to Adobe DNG. At the least your existing software will manage current RAW formats (even Wordperfect to quote another thread).

    Seems like Matt may be percieved as biting the hand that feeds him too …


  22. Stephen 11 January, 2010 at 21:27 Reply

    Interesting discussion.
    I convert to DNG on import, and have done so for a couple of years.

    I admit to being amazed regarding the ‘save’ issue. I really did not know about this. Now, I do understand that this is separate from the LR catalogue, which retains the edits I have made to images. This ‘save’ refers to saving those changes into the image data (whether within a DNG or a sidecar). Still, I did not know about it, and cannot remember reading it anywhere in Scott Kelby’s LR book, or Martin Evening’s. Interesting,

    Matt – thanks as always for posting on subjects of real interest to LR users.

  23. Kevin 11 January, 2010 at 19:33 Reply

    I’m new to this feedback stuff. Many people are asking questions here but I see no answers. Is no one answering back or What?
    My question is what changes are being saved back. All my adjustments I have made in lightroom and if so can I get back to the unchanged version. I thought that was the advantage to LR it was non destructive? Please help.

  24. xlman 11 January, 2010 at 19:28 Reply

    I wrote the last post, that i prefer NX2 because it works better with some NEF settings. OK.. BUT, I am totaly agree with this 2 post and Matt. All we need its an standard. it’s a pain works with a lot of formats. DNG its like jpg or mpeg, pdf…
    Adobe its always by the side of profesionals and make a good job giving us this ISO format. All the manufactures must adopted this DNG.

    However, today, some of us still prefer propietary software (like NX), for a few reason. I dont think Nikon adopt DNG, because at this moment, they don’t sell more any copy of NX2 (everyone goes to lightroom… or most of us), and that its a big problem $$. (dont think?)

    my two cents its for DNG, but i still waiting.
    César López. Spain.

  25. Denis 11 January, 2010 at 17:37 Reply

    My understanging is that the xmp info is saved within the dng file. For raw camera files the xmp file is created alongside the original file.

  26. Ruben 11 January, 2010 at 15:18 Reply

    When selecting all images in library mode and hitting control + s. Lightroom always says ‘saving to XMP file’. This is also the case when saving a DNG file. It this message just wrong? Or is lightroom storing the XMP file somewhere else?

    It’s a bit confusing, and VERY important to know before converting to DNG!

  27. alex 11 January, 2010 at 13:31 Reply

    All good thoughts on the DNG. To be honest, I delete all of my RAW non-keepers. There’s no point to keeping the blinking and blurred photos!

    Also- I have a completely unrelated question, though I’ve been told this is how to ask.

    I set up a “photo booth” at a party recently and would really like to be able to use lightroom to organize the photos in succession (4 vertical- just like the real old school photo booths used to do). I’ve found a way to organize the photos in the print module, but I’m wondering if there’s a way to make a custom paper size. So instead of 4 vertical photos on an 8.5×11″ page, I can make it on a 1.5×8″ page (or whatever the correct size would be). I know for printing I can just do multiples on a page and cut them up, but I’m trying to find a way that I can export directly from Lightroom and have them look like real photo booth sequences. Any ideas? Thanks!

  28. Steppenwolf71 11 January, 2010 at 13:16 Reply

    @Marty Cohen: I’m also not sure about the “Automatically write changes into XMP” thing, but if you mark *all* of your pictures and hit Command + S (on a Mac) or klick “Save metadata to file” under the Metadata menu it will now save all your settings. (take a look at your progressbar at the top left corner).

  29. Marty Cohen 11 January, 2010 at 11:51 Reply

    I am still a little confused about “And Lightroom doesn’t automatically update the DNG file if you make changes”. Two questions– (1) If you go to the Catalog menu and click on “Automatically write changes into XMP” there is a warning that “Changes made in Lightroom will not automatically be visible in other applications”. What other applications and what does this really mean? and (2) I’ve edited several thousand images in Lightroom. So, If it has been unchecked up until now, and, I NOW click on the Automatically write changes into XMP, will Lightroom save the changes into XMP for the images I’ve already edited, or only on all subsequent images I edit?

  30. Steve M 11 January, 2010 at 11:51 Reply


    Sorry if this has been covered in previous comments. I made the move to DNG about 18 months ago but for me, it’s not an either/or proposition. When I offload images from my card, I convert to DNG and place those files in my main library (actually on an external drive). At the same time though, I copy (via LR Import dialog) the original RAW file onto another hard drive. These days with disk space so cheap, I can’t see any downside to doing this. In the end, I always have my original RAW file, my DNG file, and any subsequent edited PSD files. Only the DNG and PSD files are kept in LR. And yes, I have multiple backup copies of each of those.

    Hope this helps,


  31. Denis 11 January, 2010 at 10:27 Reply

    I am a current user of several raw conversion software programs and LR 2.6, which I have used since the “beta” days, is currently the program of first choice. However I also use Bibble 5.0; SilkyPix 4.0, Qimage and Olympus Master, two of which do not offer dng support. I consider raw conversion software to be in a rapid stage of development and have not decided which software to make the sole provider.

    I have been keeping myself up to date on the question of dng conversion since the days of ACR 2.4. but have not been convinced for the need. For a few months I did some dng conversions but stopped when I realized Bibble 5.0 was not going to support dng. In LR and now with Bibble I do not use the option to write to sidecars but rely on the info being stored in the catalogs. I have both Adobe CS4 and Elements 5 but do not use ACR so if I use the “edit in ” feature in LR I send the files as tiffs using LR to process the raw data.
    I will consder converting to dng when and if I consider it necessary to preserve the ability to work with the raw camera files, using the latest DNG Converter available at that time.

  32. Kristian Z 11 January, 2010 at 10:11 Reply

    What’s this talk about “save changes”? I’m (still) using CR2 files, and wasn’t aware that Lightroom even had a “save” feature. There’s import, undestructive developing, and export (or any of the other output modules). Where does “save” come into the picture?

  33. Dustin Grau 11 January, 2010 at 09:05 Reply

    I would love to try converting all my existing NEF’s to DNG, but I have 1 lingering question: if I already have NEF’s with XMP sidecar files, and they are no longer in a LR catalog, how can I convert the original raw files AND embed the XMP data into the converted DNG file? Is the only option to re-import the files (with XMP sidecars) back into LR and convert from there? I have the standalone DNG converter utility and I would prefer to use that if it saves a re-import step. Is anyone else in the same situation or otherwise found a solution to this problem?

  34. David Crombie 11 January, 2010 at 08:16 Reply

    I decided to convert to dng for the new year but of course I quickly discovered that Windows Vista explorer cannot display dng images. No problem I thought, install the dng codec supplied by Adobe. I did this and the result was that Lightroom 2.3 and Windows Explorer could no longer delete dng files nor save metadata to the files. Both would hang if I attempted any changes to dng files.
    Thankfully I had created a restore point before installing the dng codec.
    Restoring Windows put everything back to normal.
    I have decided to continue with my Nikon NEF files, but it is a disappointment.
    I would be interested to know if any one else has had similar problems or knows of a fix for it.
    Many thanks.

  35. Mike McCarthy 11 January, 2010 at 07:33 Reply

    Actually, DNG is already an industry standard. Adobe published the ISO (International Standards Organization) documents at the Adobe Labs site so any vendors who want to use them such as Leica, Phase One, Pentax and Hassleblad are a few of the manufacturers who already incorporate DNG directly into their cameras.

    The way ISO standards work is that an organizing body controls the specification of the standard and groups can utilize that specification. Period.

    Ethernet is also an ISO standard as are many things we use every day without any thought.

    As you kind of allude to Matt, just because something is an “open” standard does not mean any one group or company can push it in any particular direction without the ISO organizing body adopting the changes and releasing a new version of the spec if the “recommendations” make sense.

    I work as an Industrial Automation Specialist when I’m not holding a camera and trust me, an open, publicly available standard isn’t a bad thing. As an example there once was a company who was a powerhouse of the industrial automation world back in the early 80s called Modicon. They were one of the first companies to allow their controllers to communicate with each other using a protocol over two wires called Modbus. The communication protocol dies a slow and painful death in the early 90s as faster and more proprietary protocols were released and Modicon was bought up by a large French conglomerate. My point? Even though the original protocol is considered dead, many companies can still use is as it was a well documented ISO standard. Today, it is cheap to use since there are no special hardware required, no licenses required and it is plenty fast enough for many applications today including building lighting and HVAC control among many other applications… 30 years after its invention. Too bad Wordperfect didn’t have the same staying power – as Tom H himself pointed out. Even MS has made it difficult to go backwards with its popular DOCX and XLSX formats since much of the corporate world still uses Office 97 infrastructure and cannot read these newer formats.

    I’ve been shooting DNG since my first Pentax K10D supported it directly in the camera and can’t imagine using a proprietary file format ever again…

    Sorry for the length. 😉

  36. Peter 11 January, 2010 at 07:12 Reply

    There is one huge issue I see with DNG that is not often talked about: As Tom mentioned in his response, DNG supports a huge variety of Bayer data formats, some of which are only ever created by the sensor of a particular camera model. However, if someone decides to write a DNG reader in the distant future, people will most likely not be concerned with supporting and testing an obscure Bayer pattern that was maybe used by 5000 people, of whom maybe only 20 ever converted their files to DNG, of which 12 are no longer alive, and 4 of the remaining 8 lost their data when their last hard disk failed, and two won’t buy the product since it is aimed at professionals and therefore way to expensive and complex to use for them. So why should the software company make that investment and support that particular format? Especially if there are no example files of that type available for testing during development?
    Thus, using the defaults in the DNG conversion settings may be likely to produce files that are not significantly more secure for the future than the original RAWs, yet the promise of the DNG file format gives users a false sense of security.

    Converting with the “Linear Demosaiced” setting will eliminate the problem, however, it has several downsides:

    – It uses the converter’s debayering code. If better demosaicing algorithms are developed in the future, or if the raw converter of choice has superior algorithms or does something special before or at the debayering stage, the user can no longer take advantage of that.
    – The user needs to know about the issue, since “Linear Demosaiced” is not the default setting in the Adobe DNG Converter. Most users trust that the defaults will work fine for them.
    – Demosaicing is part of the RAW conversion process, i.e. a linear demosaiced DNG file is no longer equivalent to the RAW from the camera. This ties in with my first point. File size will theoretically increase as well since bayer encoded images only use half resolution for the blue and red channels, whereas debayering blows them up to the same resolution as the green channel (at least in a standard Bayer pattern).
    – It is hard for users to judge how common their sensor format is. In case of Foveon chances are that people know that their sensor is different, but especially in the obscure sensor case, users might not even suspect it.

    I’m not saying that DNG is bad, or that there is a better solution available, but that people should be made aware of the problem instead of the promise that their files will be readable in the future since “it’s DNG”. Just because an application can handle DNG files does not mean it can handle all DNG files.

    There is another thing: By expressing your unwillingness to deal with terms like “Linear Demosaiced” as a user in your last post is setting quite a dangerous example as it leads people to think that such settings are not important choices to make. That setting might determine whether or not some persons files will still be readable in 50 years or not, and it being removed would be quite a shame.

    That 15-year-old kid argument doesn’t really hold up for me. Trust me, 15 year olds have more interesting things to code than a converter for an ancient highly complex file format that – in the best case – their grandfathers camera created and for which no specifications are published at all, just so they can see the seven or so files that are still on readable storage. Reverse engineering a complex file format is a way too frustrating process to be worth it.

    Another problematic yet common mindset I come across a lot is the notion of “as soon as they stop supporting my camera’s file format in the newest DNG converter version (or version of Camera Raw/Capture NX/Capture One Pro/…), I’ll convert my files to DNG with the last converter version that still supports them.” that many people seem to subscribe to. But what about that hidden CD with photos inside the wedding album that was put on a shelf and was forgotten for years? One can be sure that it is only found when the last computer that would have been able to run the last DNG converter that could still convert the photos to DNG has been thrown away …

  37. Ruben 11 January, 2010 at 06:10 Reply

    I like the DNG format and as a IT-guy i can see all the benefits and (sort of) hate manufactures for not embracing one format.

    A question on the saving changes to the DNG file.
    I have recently converted a lot of images in my catalog to DNG, (it was just before the previous post :-)). What happens to those images. The changes/edits i made to them in Ligthroom are stored in the catalog now (correct right?). I all those changes saved to the DNG file, how whould i do that ‘the easy way’?

  38. Barry Pearson 11 January, 2010 at 05:27 Reply

    ISO are currently using DNG in their 5-year revision of ISO 12234-2 (TIFF/EP). It appears likely that profile 2 of the revised version of the standard will be based on version of DNG, and it will use the DNG extension.

    The workings of ISO are secretive, but this news has been appearing in summary reports over the last year or two. See, for example:

    DNG is the only raw image format recommended by the US Library of Congress for digital image preservation. It also features in dpBestflow:

    I have about 30 pages on DNG at my (free, no pop-ups, non-commercial) website. (I started to use it in October 2004!)

  39. Denny 11 January, 2010 at 03:43 Reply

    Just so I get this straight…I have to click “Automatically write to XMP”? I know that DNG doesn’t have XMP sidecar files but I am assuming that checking that box while having DNG files means it will write directly into the DNG file, correct?

  40. Torbjorn 11 January, 2010 at 03:28 Reply

    It’s also an extra backup of sorts. Should you for some obscure reason loose your catalog file and all backups of that, you won’t loose, for instance, keywords and star ratings. (Unless, of course, the images themselves are lost …)

    I have the option for automatically saving changes turned on, as it makes sense to me to have the information in the files themselves, not just the catalog.

  41. BooneJS 11 January, 2010 at 02:06 Reply

    Wow… I’ve converted to DNG on import since the second day of owning LR1, but I never knew about the ‘save’ feature. I guess I’ve never needed it? When I send my images to Photoshop or Nik Software’s Complete Collection, I do so from within Lightroom (and it always applies my non-destructive LR changes, so I’m not starting over). When I create my final “proofs”, I Export to highest-quality JPEG.

    Is “Saving” a DNG, or writing out a .CR2 or .NEF XMP sidecar, only required when you plan on opening an image in another editor from *outside* Lightroom (ie. not use Lightroom’s “Edit In ->” option)?

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