Import CR2 files show defects in LrC

[Rob.H]

Lightroom Version Number

13.3

Operating System

1. Windows 11

Hi, this is an issue that pursuess me since a long time, several years. Does not depend on the new LrC / Camera RAW version, I've seen it throughout different PC generations since LR 6 or so. Especially some of my older CR2 files taken with EOS 7D show as defective in LrC and PS but do not in windows explorer or Canon Digital Photo Professional (DPP). In Bridge grid view the pics first are shown correctly, the error is added after some seconds. Looks like it is a problem of Camera RAW. I Created dng files from them with Adobe DNG Converter, the defect is transported to the dng's. Sometimes it is really annoying. Any idea what's the reason and how to get over it?

 

[clee01l]

What you are seeing is corruption in the RAW data block of the file.
The initial thumbnail is the camera JPEG produced by the camera. After a few seconds LrC will replace that with a thumbnail derived from the RAW data block. If that data block is not delineated properly, the Demosaic conversion to RGB pixels will fail. All other apps only expose the JPEG thumbnails.

Does this happen if you import the CR2 file or when the CR2 file is converted to DNG?
Older files will experience “bit rot” over time on the disk drive. If that is your situation, the only way to recover these files is to resort to one of your system backups.

Sent from my iPad using Tapatalk

 

[Rob.H]

Hi Cetus, these pictures have been imported to LrC years ago, maybe at LR 5 times already. Especially a two days series I took with Canon EOS 7D is affected. From time to time some change from a correct view to corrupted. This is independent from what I do, usually happens already when I open the folder in LrC grid view in library. Looks like it's the mentioned "bit rot" or damages from pc crashes from that time.

I was on the wrong way with explorer or Canon DPP, in grid view they obviously show the embedded jpg, in single view they show the corrupted RAW.

I have no backup from 10 years ago so I tried several things and programs if I could save or repair anything. There is another picture viewing and processing program called xnview which was able to create at least non-corrupted TIF 8bit from the CR2 originals (maybe also based on the embedded jpg). I will go on trying.

Since several years I've been running a RAID5 for my RAW's, since two years I'm running RAID6, so I hope It won't go further.

Thanks a lot for your explanation!

 

[clee01l]

I have no backup from 10 years ago

The aforementioned "bit-rot" and disk failure are the reasons the you run a system back up app on a schedule. Of course, it goes without mention that periodically you need to check the backup volumes for file integrity.

In addition to TimeMachine that comes free with MacOS, I also use Acronis (which is also available for WindowsOS) creating 3 separate backups (one Acronis, two TimeMachine) of all of my critical data including my image files that go back as far as 2007.

 

[vbnut]

The aforementioned "bit-rot" and disk failure are the reasons the you run a system back up app on a schedule. Of course, it goes without mention that periodically you need to check the backup volumes for file integrity.

Any folks want to describe how they check the backup volumes for file integrity, or give recommendations?

 

[John R Ellis]

It can be nasty when an old photo gets corrupted and then gets backed up, and you don't notice it for a year or two (or more). Very few people have backups older than a year or so. My Time Machine backups go back about 9 months (on two 20 TB backup drives). Last year I enabled "Forever Version History" in Backblaze, which isn't cheap ($0.006/GB/month, or an extra $72/TB/year).

LR doesn't have file-integrity checking built-in. The late Rob Cole had a plugin that computed checksums and stored them in the catalog, and you can probably find that archived on Github, but I vaguely recall someone saying it didn't work in newer versions of LR (not sure about that).

One thing I do is periodically delete and rebuild image previews. Re-rendering is very likely to flag corrupted files. I rebuild previews in attempts (only sometimes successful) at working around the spurious "photos modified" bugs with LR publish services.