TIP: How to Force the use of DNG sidecar files with Adobe Camera Raw

2016-06-19 • SEND FEEDBACK |
Related: Adobe, Adobe Camera Raw, How-To, Leica, Leica M, Leica M240, Leica SL Typ 601, rangefinder

See my Leica SL wish list and Leica M wish list at B&H Photo.

Modification of orginal RAW files is in my view a risky game: files can be potentially be damaged, modified files are very large and have to be backed-up in their entirety, original shooting settings in the DNG are masked or overwritten. Basically, I prefer to think of my RAW files as original negatives/slides; I do not want them modified—ever. This has implications for forensics and law enforcement as well. Originals should be unaltered originals.

Unfortunately, at least in Photoshop, Adobe Camera Raw does not respect its own sidecar preferences: opening a DNG file modifies the file, writing/overwriting internal data as well as changing the file modification date. Each to his own, but I find this very annoying for backup, sorting by date, etc.

Adobe Camera Raw Preferences for DNG sidecar files

Solution: lock DNG files

The lockDNG and unlockDNG scripts are trivial. They lock or unlock all DNG files in the current directory, using the command line in Terminal. I save them as executable scripts in my PATH.

#!/bin/sh
# lockDNG ©2016 DIGLLOYD INC
# LOCK all DNG files in current directory, recursively
find . -name "*.DNG" -exec  chflags -v uchg {} \;

#!/bin/sh
# unlockDNG ©2016 DIGLLOYD INC
# UNLOCK all DNG files in current directory, recursively
find . -name "*.DNG" -exec  chflags -v nouchg {} \;

Using the lockDNG and unlockDNG commands is simple:

# type 'cd ' then drag desired folder into Terminal window. Example:
diglloydMP:DIGLLOYD lloyd$ cd /Volumes/Archive/2016-0606-TripPhotos 
diglloydMP:2016-0606-TripPhotos lloyd$ lockDNG
./LeicaSL/2016-0606-LeicaM240-WhiteMountains/L1000602.DNG
./LeicaSL/2016-0606-LeicaM240-WhiteMountains/L1000603.DNG
./LeicaSL/2016-0606-LeicaM240-WhiteMountains/L1000604.DNG
...

# Unlock DNG files
diglloydMP:2016-0606-TripPhotos lloyd$ unlockDNG
./LeicaSL/2016-0606-LeicaM240-WhiteMountains/L1000597.DNG
./LeicaSL/2016-0606-LeicaM240-WhiteMountains/L1000599.DNG
./LeicaSL/2016-0606-LeicaM240-WhiteMountains/L1000600.DNG
...

When a DNG file is locked, this forces ACR to use sidecar files. It has some hassle factor: reorganizing/moving DNG files requires unlocking them. The OS X Finder shows lock icons once locked.

Locked DNG files: forces Adobe Camera Raw to use sidecar files