How export jpg from corrupt dng?

[DavePinMinn]

Yeah, it seems like it should be easy...  Windows 11, LR 13.5.1.

I have a dng file that Lightroom says is corrupt.  And there appears no way to have Lightroom FIX the corruption, so I'd like to save the good-APPEARING jpeg from the file.  The backup dng, created at the time the DNG was created with no error, is ALSO bad.

I've tried exporting it - and yes the file type is set to jpg - it fails.

I've tried doing it from Bridge - it fails.

I've even tried sending it as an email - it fails.

In Camera Raw I can SEE the embedded jpeg, but I can't find any way to EXTRACT the jpeg from there either.

How do I make Lightroom (or Bridge) give me the jpeg that's stuck in the corrupted DNG file as a full-sized jpeg?

[dj_paige]

LrC cannot perform any task on a corrupted file. There are third party utility programs which can extract JPG previews embedded in a RAW or DNG file. I have no idea if they will work on corrupted files.

The best solution is to restore a backup of the original DNG (or original RAW).

[DavePinMinn]

That would be good, but unfortunately, the original DNG is also corrupted.  Interesting that Lightroom can display the jpeg preview, but can't export the embedded jpeg.

[Rob_Cullen]

You might also try the Plugin to extract JPGs from Previews- IF you can see previews!.

Extract JPGs from Previews Plugin

I cannot say it will work.

And in worst scenario, if you can view previews in Loupe or Full-screen, do a screen-clip, using Windows Snipping Tool or an app like 'Greenshot'.

[DavePinMinn]

Thanks for the replies.  In the end the plugin from Jeffrey Friedl wasn't useful as it only made very small extractions - the largest was about 1680 px.

Eventually, I did a brute force extraction, splitting the image into a series of layers and assembling them in Photoshop.  They were saved as .png files, then put together as a panorama in Photoshop to give me TIF images in the 3700x4800 size range.  They'll be fine for what I need.

These were older images that may have been converted during the period when it appears the DNG converter wasn't always perfect, so it's fortunate that only 2 of the thousands of images had problems.  Hopefully.

[dj_paige]

In the end the plugin from Jeffrey Friedl wasn't useful as it only made very small extractions - the largest was about 1680 px.

That's what is is supposed to do, it extracts whatever preview LrC has created, in this case 1680px.

[DavePinMinn]

Then it worked perfectly...