Why is LightRoom not seeing the bottom 3/4 of image?

[bkorb]

It was okay when I first started working on the photo, but suddenly decided (in the develop module) that the bottom half was black. Exporting to PS showed a black bottom half, so I went back to the Loupe view. A-OK. Back to develop, black bottom. Back to Loupe, now a black bottom 3/4. I looked at the .NEF file and it was untouched, so I removed the .XMP. Still black bottom 3/4. I went back to the SD card and re-imported the file. For a brief moment, I saw the whole photo, but within 2 seconds, the bottom 3/4 was black. If I can figure out how to attach images, I'll attach one .PNG from OS/X showing the blackened image and another from Linux using DigiKam with the entire image present.

THIS IS A SERIOUS PROBLEM.

The question, do I need to do more diagnosis, or can I send in the non-working-for-LightRoom .NEF image as a bug report?

[bkorb]

These photos are the same files on shared drives, so the actual .nef content is the same:

[dj_paige · Accepted solution]

This is a corrupted file.

Many programs use previews to show you the image, and the image in the preview may not show the corruption. That is why, in LR, after you import the photo, you see the entire image for a few seconds (the preview in the NEF file doesn't show the corruption) but then LR generates its own rendering of the raw image, and since the file is corrupted, part of the file appears missing.

The corruption is caused by some hardware error in the chain of events, it could be a bad camera card, bad transmission to the computer, bad hard drive or even bad memory chips.

Lightroom never changes the image portion of your files, so the cause can't be Lightroom.

[bkorb]

That is, indeed, very interesting because I can edit the photo with DigiKam. Unless the camera pre-loaded the .NEF with a full size preview, DigiKam would have had to extract ... I guess that is what happened. I pulled up another RAW photo editor. It saw the full scale image, but I forced it to re-interpret. Same problem.

So, instead of a bug report, an RFE (Request for Enhancement):

* take note when there is a substantial difference between a preview and a newly derived one

(yes, I know there are ways to force this to happen, but warnings are nice things)

* provide an obvious way to extract the best available .jpg file

In my particular case, I wasn't enthralled anyway. What might have been a cull is definitely a cull.

[dj_paige]

In my particular case, I wasn't enthralled anyway. What might have been a cull is definitely a cull.

You would be wise to try to determine the hardware cause of this problem, because it will most likely happen again, but on photos that are not culls.

Also, this is not the right forum for feature requests.

[bkorb]

Maybe so. I don't quite know where to look. I was re-processing an 18 month old SD card and two images had the issue. This image was a cull. One that was not already had a successful .TIF. Clearly, the data were all there a year ago during the first processing. (I've learned some new techniques and wanted to apply them to an old shoot.) So it seems the SD card degraded somehow over the past year. Since that SD card was only written to once, this ought not to have happened. I could do a bad sector check, but I don't trust it anymore. It's only a $5.00 32GB card, so I'm going to keep it as an archive and mark it "BAD". (For those who don't know, SD card images do degrade over time, if you don't refresh the data. But it should be stable for a few years -- much more than just one.)

Here is a good writeup on flash memory: What's the life expectancy of an SD card? - Super User

[dj_paige]

As I said, the problem could be anywhere in the entire chain of hardware. You need to test importing this photo with different hardware, and on a different computer if at all possible.

[bkorb]

Thank you. The two image copies were from two separate imports -- in fact, using different card readers on different platforms (Linux and OS/X). Since I've processed well over 10,000 images in the intervening year, I will assume a degradation of the medium. Thank you tho, for suggesting other possibilities.