Luminous Landscape Forum

Raw & Post Processing, Printing => Adobe Lightroom Q&A => Topic started by: dreed on April 23, 2012, 01:22:40 am

Title: LR and data reliability
Post by: dreed on April 23, 2012, 01:22:40 am

Is there any scope within LR for it to have some concept about how reliable the data in the file is?

Does it, for example, store a checksum such as MD5 or SHA-1 of the file's contents and alert users if it changes?

Title: Re: LR and data reliability
Post by: madmanchan on April 23, 2012, 03:56:50 pm

Hi dreed,

DNG images contain a checksum (DNG tag is RawImageDigest).  When the image is loaded in ACR or Lightroom, we compute the checksum from the image data itself and check the result against the checksum stored in the DNG.  Thus we can detect unexpected changes (e.g., file corruption).  For example, ACR will warn about a damaged file if there is a checksum mismatch.

We do not yet have a built-in way in Lightroom for the user to run this "verification" procedure in batch mode (i.e., select a bunch of DNGs and run the check). 

Title: Re: LR and data reliability
Post by: dreed on April 24, 2012, 11:50:19 am

Quote from: madmanchan on April 23, 2012, 03:56:50 pm

Hi dreed,

DNG images contain a checksum (DNG tag is RawImageDigest).  When the image is loaded in ACR or Lightroom, we compute the checksum from the image data itself and check the result against the checksum stored in the DNG.  Thus we can detect unexpected changes (e.g., file corruption).  For example, ACR will warn about a damaged file if there is a checksum mismatch.

We do not yet have a built-in way in Lightroom for the user to run this "verification" procedure in batch mode (i.e., select a bunch of DNGs and run the check). 

Ok, so if I'm editing DNG files then at least I'll be warned that something is amiss when I start to work with a file, that's great!

But what about those of us that aren't storing DNG?

Are there any plans to calculate a checksum for non-DNG files and store that in the database?

I'm thinking that this would also aid duplicate image detection?

Title: Re: LR and data reliability
Post by: sbay on April 24, 2012, 10:20:08 pm

Quote from: dreed on April 24, 2012, 11:50:19 am

Are there any plans to calculate a checksum for non-DNG files and store that in the database?

I'd love to see a solution for this built into lightroom (currently using an external program for this).

Title: Re: LR and data reliability
Post by: quid666 on July 27, 2012, 06:39:40 pm

I agree that it is essential that a high-profile DAM tool such as Lightroom includes a way to check the integrity of the asset. The worst thing with data corruption is that it is a silent process: if one doesn't happen to look at a particular photo one may never know that it is corrupted.

I put a feature request forward to implement an automatic photo integrity check into Lightroom:
http://feedback.photoshop.com/photoshop_family/topics/photo_integrity_check

If this function would also be important to you please feel free to add your vote.