P: Converting raw files to lossy DNG sometimes results in purple-cast previews in the Library module

[Carlos_Oliveras]

I convert whole folders of raw files to lossy DNG on a regular basis, and since earlier this year (at least), I've noticed a problem that affects a very small percentage of the files (sometimes it doesn't happen at all), but it's starting to become a little annoying.

The problem (when it happens) is that some of the resulting lossy DNG files look good in the Develop mode of LR Classic and in Camera Raw. Even the preview from Windows file explorer (and when using image viewers that display the embedded jpg preview) looks ok. But when displaying these problematic files from the Library module in Lightroom Classic, they show a strong purple cast. So, I think there is some problem with the preview generated by LR.

Like I said, this problem happens very rarely, but it keeps happening every now and then. Most of the times I am able to fix the "pink preview" by re-building 1:1 previews, or just removing and reimporting the file. But there must be something going on with the preview generation for lossy DNG files since I also read about it (or a very similar problem) in this thread: https://forums.adobe.com/message/10758722

I am using Windows 10 and the latest versions of Lightroom Classic CC (8.0) and Camera Raw 11.0, but this was happening already with some LR CC 7.x versions. Thanks.

[fuerstchristian]

sounds odd....
2) I was of the opinion that DNG is "lossless" ???????

[Carlos_Oliveras]

There are both flavors, lossy and lossless DNG. Unfortunately, they both share the same .dng extension, which (in my opinion) is a little confusing. But that's a different story unrelated to this problem, of course.
Maybe this issue happens too with the lossless version of it, but so far I've only experienced it when converting to lossy (which is what I use most of the time).

[ccastleb]

Hello Carlos,

If possible, will you please post a download link to some examples of source raw+lossy DNG pairs where this is occurring for you?

And please note the exact DNG conversion settings as well.

Thank you!

Regards,

- Chris

[Carlos_Oliveras]

Hey Chris, thanks a lot for your interest. It's a little hard for me to find examples (because when it happens, I usually rebuild previews until the problem is gone, and also, when I convert, I delete the original raw files at the same time). But thanks to some backup copies, I've been able to locate a couple of raws where this happened later on when I converted them to DNG. 

I don't know if it's relevant, but they were shot in raw+jpeg mode, so I'll include the jpeg just in case. Also, while I only find this issue every now and then, in this case it affected 2 files in a row, and I've found another case where also 2 files in a row were affected. It doesn't seem like a coincidence...

Anyway, you can download the files here (I've included a screenshot of how they look in my LR library):

http://photoshopeando.com/descargas/otros/purple_cast.rar (78 MB)

I will include an image with the settings I use every time I convert a folder of raw files to lossy dng.

Anyway, I am not sure you will be able to replicate the problem with these files because normally, if I remove and reimport the "pinkish" dng file (from LR Classic CC), the issue is gone. In fact, I've tried to re-convert these raw files to dng with a new catalog, and the issue didn't happen. So, maybe there's nothing special about the files themselves... maybe there's something else, but I can't see the trigger or pattern.

Please let me know when you've downloaded the .rar file so that I can delete it from my server (but there's no hurry). Again, thanks a lot for your interest in looking into this.

[ccastleb]

Thanks, Carlos. 

I am unable to reproduce this so far, but as you mentioned the behavior seems intermittent. After checking our internal bug database, there was a similar issue fixed for the last public release of Lightroom Classic CC version 8.0. However, there is still the possibility of the bug occurring under certain conditions such as a threading race condition, which might explain the intermittent reproducibility you have been experiencing. If you have updated to Lr Classic CC 8.0 and still see this happening occasionally, please let me know.

Regards,

- Chris

[Carlos_Oliveras]

Thanks for having a look at this and trying to reproduce the problem, Chris. Yes, I am using LR Classic CC 8.0 (build 1193777).

Like you say, it seems like something intermittent. So far it hasn't been a huge problem (in fact, it happens very rarely, and while it's annoying, it's also easy to fix), but from now on, I'll try to pay more attention when converting files, just in case I notice any pattern or possible trigger. If so, I would post any finding in this thread, in the hopes that it can provide some clue. Or maybe it won't happen again! (I'll keep my fingers crossed).

Kind regards,

Carlos

[kenth13086284]

Hello. I am also having this issue. Using Adobe DNG converter 11.1.0.112. on Mac OS 10.14. Some images the color is correct but some come out red or pink. This only happens when using compression. If I do a non compressed convert then no color problems occur. 

The strange thing is it's not all of the files only some from my camera turn pink. however when it does happen it's 100% repeatable. I can't ever compress that file without it turning pink or red. 



I'm assuming that Photoshop and DNG converter share a code base and therefore are sharing this bug? Also it seems to be platform agnostic as I'm on OSX and the OP is on windows.

Here are some example files, original, converted uncompressed, and converted compressed.
https://drive.google.com/file/d/1onG6M0QAlypEAQ7X5xC4iaIsOnMN9rhq/view?usp=sharing



UPDATE:
I tried this now.
Convert Cr3 to DNG(uncompressed) with DNG converter 11

Then I used DNG converter 7.2 to convert that DNG(uncompressed ) to DNG(Compressed)

That worked! No color issues. So it seems that the newer DNG converter has a bug that is not in the older software. 






Chris Castleberry can you comment on this? Is this the right place to report this issue or should it be forwarded to somewhere else?

[MQI]

Hi Kent, we are having trouble reproducing this issue in house on Mac OS 10.14 (and 10.13) using DNG Converter 11.1. We also tried with your .cr3 image - still can't repro. Two questions:1. Are you positive you are using DNG Conveter 11.1.0.112? you can find this info by clicking on "About DNG Conveter"
2. Can you always see this issue with just converting this .cr3 file by itself or with a bunch of other files?
3. Could you provide more details on the exact step you did with "This only happens when using compression"? Perhaps a screenshot?


Thank you.
Michelle Qi

[kenth13086284]

Hi Michelle!

Yes I am sure.


2. Yes every time I convert this cr3 file it is pink when using (v11) with compression on. By this I mean Change Preferences -> Check Use Lossy Compression.

3. If I convert the cr3 file to dng with no compression I dont see pink. (v11). By this I mean Change Preferences -> Uncheck Use Lossy Compression.


4. If I take the dng file from step 3 without pink and run it though v11 again this time with lossy compression on it will also be pink.

5. If I take the dng file from step 3 without pink and run it though v7.2 this time with lossy compression on it will not be pink and it will be compressed.


Basically right now I have to run the file through two different versions of DNG converter first to go from cr3 to dng(uncompressed) then the second to go from DNG to DNG(compressed)


Also to clarify. Some photos turn out pink when being converted and some don't. But they are consistent. The ones that will turn pink always will turn pink no matter how many times I run the software on the cr3 file.

Additional information. They dont all turn pink. Some turn red. Some turn a copper color like a old sepia photo. but whatever color they turn is consistent every time they are converted.

[kenth13086284]

Michelle please let me know if you need more information or some kind of log file. I'm happy to help get it fixed.

[MQI]

Thank you Kent for your responses and detailed info! We can reproduce what you're seeing in the Finder/Preview. This appears to be an issue with Apple’s preview software. We’ve logged the issue with Apple. Hopefully they will fix it in an upcoming OS release.

Thanks again.
Michelle

[kenth13086284]

Hi Michelle. Thanks for the info. I'm curious why is 7.2 ok but not v11? Am I loosing some image data using 7.2 to compress verses using v11?

[Carlos_Oliveras]

About my original issue, I've noticed an improvement. It probably improved with LR Classic 8.1, but I'm not absolutely sure since when things got better.

Anyway, the thing is that,  while the purple-cast preview generation still happens every now and then after converting a folder of raw images to lossy dng, now it's much easier to correct it:

- If I rebuild the preview manually (Library>Previews>...), it will fix it. Previously, it did nothing - I had to remove the image from the catalog and import it again to have LR really rebuild the preview.

- If I select a "bad" preview image and then switch to the Develop module, the image will be displayed correctly. This was already happening, but the problem was that, when returning to the Library module, the weird preview was displayed again. Well, not anymore - now, the correct preview "sticks", when going back to Library so, if I find any bad preview, I don't even have to rebuild the preview, I can just switch to Develop, then back to Library, and the preview is ok.

While this is not a complete fix, it's enough to quickly correct any "bad" preview, should it happen.

Thanks for your continued improvements in LR Classic.

[Todd Shaner]

Chris Castleberry,  I discovered a similar magenta/pink discoloration issue at the below Lightroom Forum post.  This happens when applying a Spot Removal Tool Clone spot to a raw file and then exporting it to DNG file format with use 'Lossy Compression checked. The returned lossy DNG file  exhibits a strong magenta/pink cast in the clone spot.

EDIT: Just tested this on a Windows 7 system using LR 5.7.1 with Export DNG Compatibility set to 'Camera Raw 7.1 and later' and 'Lossy Compression.' It does NOT exhibit the issue.

[xinaesth]

Yes, I just tried converting to lossy DNG for the first time and noticed a similar problem.

If you move the spots significantly it prompts it to re-compute any 'dirty' areas properly.

[Todd Shaner]

I see the same behavior. Clone or Heal spots are not being properly applied to the lossy DNG image data. Moving the clone/heal spot slightly causes it to be properly reapplied.
As I mention above LR 5.71 does NOT exhibit this issue so something was changed in the LR/ACR lossy DNG conversion process that's causing the issue.This post is still marked 'In Progress' so hopefully it will be fixed in the next update.

[FeedbackCommunityMember]

To anyone still experiencing this issue...

I came across this thread (and several others) looking for a solution to a magenta cast on files converted from RAW to DNG using the Adobe DNG Converter.. So I noticed many people were experiencing the same issue; however, in some cases conversion was working fine before (without the color pink/magenta cast) with a previous version of the program.. This was important.

In my case I solved the problem by using the command line option: -dng1.3
While the default (-dng1.4) does produce the undesirable color cast.

To set the DNG version on the program GUI:
Preferences -> Compatibility -> Personalized/Custom -> Version -> DNG 1.3

Hope this helps!

[Todd Shaner]

I've found the reason only some Lossy DNG export files exhibit the green tint in the Library Preview. The image has to have a crop applied and 'Resize to Fit' selected in the Export module. To demonstrate:

1) In the LR Develop module crop a raw file to about 3000 px long edge.
2) In the Export module select Image Format DNG, check Lossy Compression, select Resize to Fit Long Edge 1000 px and export.

The Lossy DNG file will appear with a green tint in the Library module and appear normal in the Develop module. If the file is exported it also appears normal with no green tint so this is strictly a Library Preview issue. In addition the long edge will be less than the 1000 px selected in the Export module. So there are two issues! In the below example the 6016 x4016 NEF file was cropped to 4042 x 2698 and then exported using the above settings. Note the long edge of the export DNG file is 672 px and not 1000 px.



It appears Nikon NEF files exhibit a green tint, but Canon CR2 files exhibit a pink tint as mentioned by others in this post. Here's a Canon 600D CR2 file example:

[Carlos_Oliveras]

I agree with Todd - I haven't bothered to post anymore in this thread since sometimes I get tired of "working" for the LR team (assuming there is such thing as a LR team). But yes - some time ago I also did realize that most of the dng's with green/pink casts were created from raw files where a crop had been applied.
However, I still experience this problem with some raw files without a crop, so I guess there's something else going on. But then again, it looks like applying a crop and then converting to DNG increases the chances of this problem arising.
Anyway, as with so many other LR-related bugs, I've just given up on hoping they'll fix it, and I've just learnt to live with it.

[Bob Somrak]

Amazing sleuthing job there Todd.  Well done.

[Todd Shaner]

"However, I still experience this problem with some raw files without a crop, so I guess there's something else going on."

I notices that as well. Some files exhibit the issue with no crop applied. No idea why, but Adobe should be able to duplicate issue as I outlined.

[Todd Shaner]

I just discovered that using Sync from the original file with 'Check All' selected fixes the lossy DNG pink square Spot Removal issue. Give it a try.

[Todd Shaner]

I just made another discovery concerning the pink square Spot Removal issue using LrC 10.3. If you uncheck 'Embed Fast Load Data' in the Export Module> File Settings Spot Removal works properly with no pink squares. So we have another workaround. I also noticed files synced to the Web in LrC 10.3 work properly with no Spot Removal pink squares.

[sameerp13]

I have the same issue, some intermittent pictures that are imported in Lightroom (LrC 11.0) has a pink tint on it. I came to conclusion that it is something to do witht he way Lr coverts my RAW (CR3) to DNG. I tried to disable "Embed Fast Load Data" option in Lr, but in vain. Interestingly this tint is only visible outside of Lr. Also, it is not visible in RawTherapee. I used Adobe DNG converter and applying this technique of disabling "Embed Fast Load Data" coverts the image without the Pink Tint. Then I can import or add to Lr's catalog. This is one of the most annoying flaw in Lr I have found. Needless to say so many of my imported pics have this tint and does not look good. I think my saving grace would be to re-export them, so far I have tried to export the tinted pics in jpeg and it does not show any pink tint.

[Rikk Flohr: Photography]

This is an older bug that is no longer reproducible under the current Operating Systems and Lightroom versions. We are closing this bug. Should a similar bug arise, please create a new bug report. This thread will be closed.