DNG as an archival format

I'm in the process of archiving all my images, and it's time to decide whether to stick with archiving CR2 files, or whether I should be converting to DNG and archiving those. Does anyone have any useful thoughts, opinions, relevant articles, or experience with DNG inside Photoshop Bridge?

My current archival plan is:
- RAW format on a hard drive in an off site location.
- RAW format on a hard drive in my home, not connected to my PC.
- JPG format online on my PC at home (quick reference/worst case backup).

When I used CS2 and Bridge I switched to DNG for one reason mainly; no more XMP files to move with the CR2. Then I switched to LR which maintains a database but I still use DNG so that I can write the chagnes directly to the files if I choose.

I currently have the following workflow (which I am sure differs from those whom shoot professionally):

Import from CF card to LR, converting to DNG.
Backup copies of original CR2 files to a folder for DVD burns (unedited files)
Backup my LR database every night to an external drive.
Backup all photos on my internal to an external drive.

My advice is this,
Archive in CR2 format for now as that is the original file.
At some point given we are talking digital technology, you will probably have to re-archive to a different media to maintain currency of the data. At that point if DNG is still looking like the best format for long term archive then convert to DNG at that time as you are copying to the new media.
DNG is still too new and lacking enough support to consider it an archive format, although I have hopes it will take off.

The alternative is to archive one copy as CR2 and the other as DNG. This will cover you just in case one of the formats goes bye bye. You should have at least two archival copies anyway just in case.

As to the DNG format itself, It does not seem to have any effect on the image itself, but may lose some of the proprietary metadata in transit. How much the metadata that is lost will affect the final usefulness of the data is probably unknown at this time.

The instant Canon adopts DNG as a camera output format is the day I start converting everything. Until then i am personally sticking with CR2 for my archive format.

I archive to DVD+R and external drives.

I'm going to archive one copy in CR2 and one in DNG, just to hedge my bets. Takes a lot of storage this archiving business!

I convert everything to DNG upon Lightroom import. Before lightroom, I used Adobe's DNG converter....as mentioned earlier, no more xmp files - and since Adobe is in the forefront, I am placing my bets on the DNG format down the road.

I started an all new archive and Digital Asset Management routine after reading Peter Krogh's book "The DAM Book".

I haven't deleted any original CR2 files, but they are all renamed the same as the DNG's, and stored in their own matching folder hierarchy, where I never touch them.

There is an excellent discussion forum on DNG over at the DAM forum at the link below.

http://thedambook.com/​smf/index.php?board=5.​0

I would keep it a CR2 for now. DNG is a file format that Adobe is pushing and pushing hard but no one really has adopted it. Anyone remember Wordstar? At one time it was the defacto word processor and many large companies adopted it. We still have Wordstar documents at work and they are all but unreadable today. Framemaker is headed the same way. With CR2 you at least have a lot of other users so if and when Canon decides to change their RAW file format, you at least have a large community of other users who will be in the same situation as you.
I myself am archiving both CR2 and jpeg. I'm hoping in 20 years or more one of those standards will still be readable.

I don't think i'm going to archive to JPG, it takes a fairly massive amount of processing time. I have around 10,000 RAW images which i'm going to take offline but keep stored, converting to JPG would take 12 hours, but I tried it last night and PhotoShop died after 7000 or so images. I'm going to keep a copy on hard drives in DNG and a copy in CR2, one offsite, that seems safe enough for me. The trick is managing all the different drives and making sure everything's archived.

SWPhotoImaging wrote in post #3373549
I started an all new archive and Digital Asset Management routine after reading Peter Krogh's book "The DAM Book".

I haven't deleted any original CR2 files, but they are all renamed the same as the DNG's, and stored in their own matching folder hierarchy, where I never touch them.

There is an excellent discussion forum on DNG over at the DAM forum at the link below.

http://thedambook.com/​smf/index.php?board=5.​0

Any thread in particular.

Pack the CR2's on DVD's, a GNU/Linux live CD with DCRAW, and an ultraslim computer and screen (with generator! AC formats may change!) into a closet and never worry about it again; now you'll always be able to access your data.

I don't trust DVDs to store essential data. I've lost data from CDs, and DVDs are less reliable.

DVDs less reliable than CDs? Aren't they supposed to last like 70 years longer?

They're both meant to last at least 100 years if you buy good quality media, which I do, but i've had CDs that are unreadable after just 5 years. I just don't trust them.

tim wrote in post #3373974
I don't trust DVDs to store essential data. I've lost data from CDs, and DVDs are less reliable.

Use archival DVDs. They are a few pennies more expensive, but are reliable as heck. I operate a large lab and we have to backup nearly 100 different machines and have not had a DVD failure since switching to archival media. I have found that the most reliable is Taiyo Yuden media although many have taken to putting out fake TY media. There are several web sites discussing the benefits and the fake TY disks. Do a Google on "Taiyo Yuden FAQ fake" and you'll get a bunch of sited discussing the media.

tim, what do you backup on, then?