Needing to preserve edits of DNG files for Laser Scans and have a deadline by next week, any help would be useful, thanks!

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aarongoldstein7

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This problem is quite complicated and probably going to require some deep thinking, but nevertheless, here we go!

Essentially, I have a collection of .dng files from 4 firefly cameras that are used in combination to create a stitched 360 image. These 360 images (also known as panos) will be used for the colorization of a laser scan and used as a virtual 3D tour, which is all handled in a 3rd party processing software. I have been asked by the client to blur any faces of individuals on site that may be in the photos for confidentiality purposes.

Here's where it gets sticky:
  • When uploading to the processing software, the resulting images must be in .dng format in order to correctly work with the laser scan data.
  • Obviously any edits made to a .dng in Lightroom is handled as instructions rather than permanent edit
  • I have tried exporting as a .jpg and then converting back to .dng, but this does not appear to work

Does anyone have any suggestions on other softwares I should be using or other workflows I should be trying? Again, I need to make sure that these edits are preserved in the final .dng I upload to the processing software.

Thanks for the help!
 
I have tried exporting as a .jpg and then converting back to .dng, but this does not appear to work
Welcome to the forum. What is exactly not working? Can you describe it in more detail? And have you tired saving the image as a TIFF file and then converting?

--Ken
 
Obviously any edits made to a .dng in Lightroom is handled as instructions rather than permanent edit
If you simply save metadata back to the DNG, true.

However, you can export as DNG or use the menu Metadata > Update DNG Preview which rewrites the DNG's embedded picture so that it matches what you see in LR.

It then depends what the processing software does. If it processes the raw data, you're back to square one. If it simply extracts the embedded preview, fine.
 
Welcome to the forum. What is exactly not working? Can you describe it in more detail? And have you tired saving the image as a TIFF file and then converting?

--Ken
Hey Ken, thanks for asking! Basically, I'm making some big blatant edits to the photos in LR (using a radial brush with temp in opposite direction as photo) and the edits are not being preserved when I upload them to a 3rd party program for processing.

I just trialed exported as a TIFF and then exporting as DNG to get it back as a DNG since I've been told by support that the image must be uploaded as a DNG. This worked in that the images were recognized and used, but none of these edits are being saved. I'm trialing this, since I need to actually blur people's faces out.

Other things that haven't worked:

-I updated and saved the metadata after the edits were made and exported as a dng. This was recognized by the software but the edits were not retained
-I exported as jpg, but was not recognized by the software at all
-I exported DNG to JPG and then back to DNG, but was not recognized by the software at all
-I exported as TIFF and then to DNG. This was recognized by the software but the edits were not retained.

Thanks!
 
If you simply save metadata back to the DNG, true.

However, you can export as DNG or use the menu Metadata > Update DNG Preview which rewrites the DNG's embedded picture so that it matches what you see in LR.

It then depends what the processing software does. If it processes the raw data, you're back to square one. If it simply extracts the embedded preview, fine.
So I did try this approach, and it did update the preview. I was hopeful that this would work, but unfortunately it did not. The photos were recognized, but the edits were not retained.

Sadly, I think you're right about the software actually processing the raw file. Any other thoughts?
 
[*]Obviously any edits made to a .dng in Lightroom is handled as instructions rather than permanent edit

There is no reason to expect the image in the Derivative DNG file format to be unedited or even RAW. DNG is a file specification. The data block can contain RAW data or edited RGB data just like TIFF or even like a lossy JPEG.
If you create a Panorama or HDR in Lightroom the image that results is an edited image in DNG format. This is probably what the specification refers to when require information the file that you produce be in DNG format. How else are you going to blur the face pixels other than a permanent edit to the areas that you identify as faces?


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Hi Cletus,

Thanks for the reply. Do you have any recommendations on what routes I could try? I'm pretty deflated after trying all these different things and nothing seems to have the answer

Thanks
 
Hi Cletus,

Thanks for the reply. Do you have any recommendations on what routes I could try? I'm pretty deflated after trying all these different things and nothing seems to have the answer

Thanks

What are the requirements from the client? It seems to me that you are needing to blur the faces on all of the images and export as an RGB DNG file (not as “original”). These files will be showing blurred faces when viewed. If you do not need to create the panoramas, then you are done.
If you do need to create the panoramas, then you might create the panoramas from the original files first in Lightroom Classic and this will save them as a DNG file format. You can further edit the Panoramas to blur the faces and then export the panorama as a DNG file format.


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What are the requirements from the client? It seems to me that you are needing to blur the faces on all of the images and export as an RGB DNG file (not as “original”). These files will be showing blurred faces when viewed. If you do not need to create the panoramas, then you are done.
If you do need to create the panoramas, then you might create the panoramas from the original files first in Lightroom Classic and this will save them as a DNG file format. You can further edit the Panoramas to blur the faces and then export the panorama as a DNG file format.


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Yes, the images only need to have faces blurred. The stitching process is all taken care of by the 3rd party processing software. So with that being said, how would I export as a RGB DNG file?
 
Why did the export JPG + import as DNG not work?

And what if you send them Lossy DNGs?
 
Unfortunately, I have no clue. I'd imagine it has something to do with the the 3rd party program? Maybe the original metadata got screwed up?

What is the difference between a Lossy DNG and the original DNG and how would I export it as such?
 
Unfortunately, I have no clue. I'd imagine it has something to do with the the 3rd party program? Maybe the original metadata got screwed up?

What is the difference between a Lossy DNG and the original DNG and how would I export it as such?

There can be may types of DNG file. A RAW DNG is not an image but the data block contains individual values from the sensor photo sites. To convert a RAW file so that you (and other software) can see an image, there is a process to combine individual photosite values int their color pixels. This is called demosaic’ing. The result are RGB pixels. Once the data is in RGB pixel form, it can be saved. It can be saved as a JPEG, a TIFF, a DNG or any number of other RGB image file formats. When saved as DNG, the data block now contains RGB pixels.

When saved, the data bloc can be compressed to make it smaller or uncompressed. A Lossless compression algorithm will produce the same pixels when the compressed file is Reexpanded for viewing or further processing. A lossy compression produces a smaller file but you do not get the same pixels back when re-expanded. IOW, pixels are lost and not recovered. JPEGs are always lossy compression and pixels get lost every time you save the JPEG. This is why it is recommended that you Shoot and save in a Lossless RAW format. Many manufacturers create their own proprietary RAW formats like CR2 of Canon and NEF for Nikon. Some manufacturers use the public DNG file format and place the RAW data in the DNG Data block.

No matter how your data starts off. It arrives in Lightroom Classic as an RGB pixel image. Any processing that you do to that image in Lightroom changes individual pixels. To preserve those changed pixels (including the face blurs), you create a derivative of the original image. The export process takes those RGB pixels from Lightroom and saves them as a new file. In the export dialog, you can choose the file format for the new image file that you create. Your file format choices include JPEG (which is always lossy), TIFF (which can be compressed, uncompressed, 8 bit ot 16 bit pixels etc) and finally DNG (which can be Lossless compressed or lossy compressed).

I think you want to import your original images into Lightroom Classic. Process them to include blurring faces and export them using a Lossless DNG file format. After that you can send the new exported files to the third party process for finalizing.


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There can be may types of DNG file. A RAW DNG is not an image but the data block contains individual values from the sensor photo sites. To convert a RAW file so that you (and other software) can see an image, there is a process to combine individual photosite values int their color pixels. This is called demosaic’ing. The result are RGB pixels. Once the data is in RGB pixel form, it can be saved. It can be saved as a JPEG, a TIFF, a DNG or any number of other RGB image file formats. When saved as DNG, the data block now contains RGB pixels.

When saved, the data bloc can be compressed to make it smaller or uncompressed. A Lossless compression algorithm will produce the same pixels when the compressed file is Reexpanded for viewing or further processing. A lossy compression produces a smaller file but you do not get the same pixels back when re-expanded. IOW, pixels are lost and not recovered. JPEGs are always lossy compression and pixels get lost every time you save the JPEG. This is why it is recommended that you Shoot and save in a Lossless RAW format. Many manufacturers create their own proprietary RAW formats like CR2 of Canon and NEF for Nikon. Some manufacturers use the public DNG file format and place the RAW data in the DNG Data block.

No matter how your data starts off. It arrives in Lightroom Classic as an RGB pixel image. Any processing that you do to that image in Lightroom changes individual pixels. To preserve those changed pixels (including the face blurs), you create a derivative of the original image. The export process takes those RGB pixels from Lightroom and saves them as a new file. In the export dialog, you can choose the file format for the new image file that you create. Your file format choices include JPEG (which is always lossy), TIFF (which can be compressed, uncompressed, 8 bit ot 16 bit pixels etc) and finally DNG (which can be Lossless compressed or lossy compressed).

I think you want to import your original images into Lightroom Classic. Process them to include blurring faces and export them using a Lossless DNG file format. After that you can send the new exported files to the third party process for finalizing.


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Cletus,

I tried uploaded the data with the lossy DNGs and it recognized the format. However, it doesn't appear that any of these edits were retained when the images were stitched together and corrected by the 3rd party program. Any other ideas?
 
I suspect we're all wasting our time if we don't have answers to certain questions about the 3rd party program. What is it called? Is it based on something else - eg ImageMagick. And again, what exactly is the error with JPGs?

In this last case, I'm surprised that the 3d rendering app can't handle JPG. My guess is that its task requires uncropped files and standard EXIF info about the lens, which JPG could supply (assuming you did exported with it - another question)
 
Cletus,

I tried uploaded the data with the lossy DNGs and it recognized the format. However, it doesn't appear that any of these edits were retained when the images were stitched together and corrected by the 3rd party program. Any other ideas?
Can you send one of these lossy DNGs to me at wetransfer.com? My email address is "cletus.lee(at)icloud.com". You need to substitute the appropriate symbol for (at).
 
Hey Cletus,

We got some feedback from the the software company. Apparently, the software accepts jpg files so that isn't the actual problem. I found out that there 2 things in the metadata that can't be changed: the photo orientation and the dimensions of the photo. I found after looking at the EXIF of the DNG, exported DNG, and exported JPG, that for whatever reason, the orientation tag is being scrubbed on only the JPG export. So with that being said, I'm not sure how to preserve this in Lightroom.

Do you have any recommendations?
 
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