Verifying file integrity from Lightroom 3

[nomad]

Hello,

I have noticed some random file corruption from my catalog's DNGs. The troubling part is that I have only noticed this when I need to open up the file. In other words, the previews look normal. Rebuilding the previews from lightroom does not seem to revela any issues either.

Can someone tell me if there is any kind of systematic verification method available to run from lightroom, whether via a plugin or otherwise? I have been searching this forum and others for the past couple hours and cannot seem to find anything.

Thank you.

Lucas.

[BobSmith]

I believe you could export a temporary set of DNG files (make a new DNG from your existing DNG... or other file).  That process will usually kick up an error if there's something wrong with the original file.  I believe Peter has suggested this before.  And this method of converting to DNG is a large part of what makes ImageVerifyer work.  If the new DNGs are successfully exported you have a good set of original files.  If any kick out an error, they are most likely corrupt.  If your originals are all fine, just toss the temp set of DNGs.

Bob Smith

[JoeThePhotographer]

One thing to be aware of that I have read about is that when using the DNG Conveter method of checking hashes, if the file is really corrupt, DNG converter might not recognize it as a DNG file and therefore will not flag it as damaged.  You have to count the # of dngs you have before and after running the conversion. 

I have read that ImageVerifier automates this process: it will use DNG converter to verify DNGs without actually converting them.  I haven't tried it, but it might be faster.  I don't know whether IV will tell whether a DNG file is damaged beyond recognition.

IMO, the fact that LR does not have a way of automatically checking the DNGs hashes across your catalogue is a major fumble on Adobe's part.  Actually, wait, they just had record profits this quarter.  They must know something I don't know about making money. 

Joe

[Mathew Farrell]

I just figured on a variation of this method - select all images in your catalogue and export them to the smallest possible JPG files. I export to 1px x 1px, lowest quality, etc. That way the resultant files end up something like 8kb rather than megabytes. It takes a similar amount of time to run, but doesn't choke up a load of disk space in the meantime.

The key benefit of doing this through LR rather than DNG converter is that LR keeps a record of files that failed to export. Add a keyword to each of these files (such as Corrupt), or drop them all into a new set/collection. DNG convertor simply gives you a list, rather than helping you group or tag the files in question.
Another benefit of trying to convert everything. For example, as stated above, DNG convertor can simply ignore a file that is really mashed. The LR catalogue, by contrast, expects this to be an image file and reports it as an error.