LR development history in DNG?

[braver]

The only thing which tethers me to LR is that I can see, undo and redo all of my edits to a file.  If this history is to be exported into the DNG, I'd be able to decouple it from LR and put into Aperture or enjoy separately in Bridge or Finder.  So does the current or planned DNG spec provide for the development history preservation?

Cheers,
Alexy

[johnbeardy]

No, you're better off staying with Lightroom . More seriously, I think Aperture 2.0's greater support of DNG makes moving to it more practical for DNG users (it no longer fails to read your descriptive metadata, it can read formats not supported by the OS). Most of all it's another argument in favour of DNG. On the other hand, Aperture still won't write any metadata into the DNG so there's a degree of lock in there.

It's more a question of a Lightroom design choice rather than the DNG specification which already allows Adobe to write such metadata into the XMP data. Whether it's important to write history into a DNG is very much open to debate. The adjustments metadata is written into the DNG, and that's the really important information. History? Well, who cares how you got to the current state? If you're moving work between Lightroom users (eg an assistant processing the job and showing the employer what's been done) then you have the Export/Import as Catalog route. Otherwise, where's the value?

John

[braver]

Actually, there's a lot of value in maintaining different development versions in DNG as snapshots.  Actually I tried exporting the snapshots and it worked!  In Lightroom 2 Beta, I did an import of a shot, edited it, called it a Snapshot.  Saved the metadata back to the DNG with Command-S (get your Apple on!).  Imported into Lightroom 1.41, selected it, switched to Develop -- and here it was, with snapshots called Import, Snapshot, Import 2!  (The latter was the latest one).

I can easily see doing several different things with the RAW original and calling then names in Snapshots, then sending it off and asking, what's better.  The whole thing snugly sits in the same DNG.

I like to have all the torturous decisions and doubts of the past to be recorded for posterity!

[johnbeardy]

You specifically mentioned history, not snapshots.

John

[braver]

Ah, I meant one as a part of another.  So are the snapshots the LR feature or a part of the spec?

[johnbeardy]

The existing spec left Adobe free to add metadata like this, and they do put snapshots in the metadata.

John

[braver]

Yes -- found that experimentally.  It bothers me a bit, when searching the DNG 1.2 PDF, that the word snapshot is encountered only once and apparently relates to the preview --

"A UTF-8 encoded string containing the name of the conversion settings (for example, snapshot name) used for the preview stored in the IFD."

-- I hope it gets officially included there, so that Aperture and others recognize it.

Another thing I wonder about is why ACR doesn't show the snapshots.  It's a family thing with the LR, after all.

Also -- is LR 2 Beta doing DNG 1.2 and LR 1.x doing DNG 1.1?  I see both in my metadata in my snapshot reimport experiment.
Alexy

[peterkrogh]

Alexy,
You have a number of issues you're umping together.

1. Snapshots in Lightroom/ACR.  Snapshots are written to metadata, so they are portable.   WHile it's not in ACR, a Bridge script we have will enable this:
http://damuseful.com/movies/snapper.mov.

The DNG spec does not really need to support this, since it' really about the XMP syntax as defined by the raw processor.

2. The DNG spec does, however, now provide for multiple previews to be embedded into the file (although no one does it yet).  This would enable previews from multiple applications, as well as multiple versions from one application.  The name as part of the DNG spec is soething that needs to be ther to help tie the particular settings to a particular preview.

3. Since Aperture does not own the ACR rendering engine, it wil never be able to reproduce ACR renderings using the instructions - it's just not possible to wire this up.  It *can*, in theory, make use of the embedded rendering to give the user access to the ACR work.  They just have not enabled robust use of the preview yet.

4. Snapshots predated the new DNG spec, since they are ACR specs, not DNG-spec related.

5. LR 1.4.1 and ACR 4.41 both started making DNG spec 1.2 compliant DNG files.

Peter

Peter