It’s amazing how often some Lightroom users still assert that a disadvantage of the DNG file format is that any time the metadata changes in the DNG file, you have to backup the whole DNG file again (and again). This isn’t a disadvantage of DNG – it’s a failure to re-assess and think through your backup strategy.
So as it’s now pantomime season, a deep intake of breath please, and after me – OH NO YOU DON’T!
To explain, I certainly don’t dismiss the need to back up your ongoing work, but you really don’t need to keep backing up these DNG files simply because Lightroom has saved metadata to them.
For one thing, you wouldn’t be backing up all your work, just the portion that Lightroom saves as XMP metadata. This is intended for sharing information with other programs, not backup, and means you’d be missing flags, stacking, history steps, virtual copies, assignment to collections and published collections. So the backup value of these DNGs is quite a bit less than you might imagine.
Back up the catalogue
Instead back up your Lightroom catalogue routinely – mine are set to prompt me every time I exit the program – and that’s your Lightroom work fully covered.
What about the pictures?
With a DNG-based workflow you simply back up your new DNGs. Because these “virgin” copies are safeguarding your photos, you don’t actually have to worry about the “working” DNGs which are shown in your catalogue. The virgin DNGs are your backup.
If things did go wrong, this combination of the catalogue backups and the virgin copies of the DNGs means your work and your pictures can be recovered – 100%.
One problem is that people trust their backup programs. Often we just don’t take a moment to validate that they are indeed backing up what they are supposed to do, and how confident are we that we would know how to restore our work? And we apply the same kind of lazy thinking to DNG backups. We just think that updated DNGs must be backed up.
Separate “virgin” DNGs from the “working” DNGs
But the solution really isn’t difficult – the hard thing is seeing through the assertions that backing up is a disadvantage of DNGs. Maybe our backup software can’t distinguish new or virgin DNGs from existing files which have been updated? But an even easier way is to physically separate new or “virgin” DNGs from the “working” DNGs to which LR writes metadata. Put new DNGs on one drive or in one top level folder. Once these new DNGs are backed up, they can be moved over to the drive for working DNGs – which isn’t continually targeted by the backup program.
So while a DNG-based workflow can be attacked, you really have to choose ground that is much less shaky than the old backup argument. It’s a tired old pantomime dame, keeps getting rolled out and shoved centre stage. Next time you recognise it, just remember – it’s behind you!