# JPG to DNG



## CatherineA

I'm new to photography, new to LR and new to this forum so here goes with a very basic question.  My camera only shoots JPG images and I wonder whether it matters whether I choose to Copy As DNG or just Copy. I now know that DNG is designed for RAW files but in my case, with JPG, what would the difference be in what is stored with the two ways of copying files? 

I am trying to get better organized in my approach now, but I have imported both ways and I wonder what the consequences are.

Thank you!


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## Johan Elzenga

Just use Copy. Copy as DNG would only put your JPEG's in another envelope.


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## CatherineA

Thank you Johan. I will switch to doing this from now on.  Have I lost info or data on the images where I selected “Copy as DNG”?


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## Johan Elzenga

No, like I said, you simply placed it in another envelope.


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## Tony Jay

JohanElzenga said:


> No, like I said, you simply placed it in another envelope.


And, just to be clear to the OP, you have not gained a heck of a lot either...
You have put put 8-bit data into an envelope that can contain 16-bit data, but the end result is still 8-bit data and all its limitations...

Just saying...

Tony Jay


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## BarrySchwartz

I agree with earlier comments.  Once something has been processed and compressed from a RAW file of any kind (which is what happened in the camera), there is no advantage to turning the file into a DNG because you can't make the kinds of changes you can do with any RAW file.


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## jid9p80vph

The one advantage of converting to DNG is that the DNG format contains a checksum validation feature, so you can verify that the files aren't becoming corrupted somehow.


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## Johan Elzenga

marcb said:


> The one advantage of converting to DNG is that the DNG format contains a checksum validation feature, so you can verify that the files aren't becoming corrupted somehow.


True, but that function is pretty overrated. Validation does not protect you against corruption, it's just an early warning (if you are disciplined enough to run it regularly). An 'early warning' may sound like an advantage (in case of cancer, or a fire, an early warning can save life), but it isn't really. File corruption isn't like cancer or like a fire. It doesn't spread and the remedy is the same whether or not you detect it early or late: replace the image by a backup image. Maybe I have one or two corrupted images in my archive, who knows. But as long as I don't need them, that doesn't matter. And when I do need them for something, I'll know they are corrupted. With or without validation.


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## jid9p80vph

True, but I would rather have an early warning, so I can recover the last good version from my backups before they rotate...


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## Johan Elzenga

marcb said:


> True, but I would rather have an early warning, so I can recover the last good version from my backups before they rotate...


It's very unlikely that file corruption would trigger your backup system into making a new backup copy.


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## jid9p80vph

JohanElzenga said:


> It's very unlikely that file corruption would trigger your backup system into making a new backup copy.


Fortunately, I've never had to resort to my backups yet. Another big advantage of LR's non-destructive approach .


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## Johan Elzenga

Same here. File corruption and catalog corruption only happens to people who don’t make backups. That is a well-known statistic.


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## johnbeardy

The beauty of importing JPEG originals as DNGs is that it greatly reduces the risk of overwriting the files by editing them in Photoshop. Lightroom edits can also be safely saved back to these DNGs, allowing other applications to see the image's LR-adjusted appearance.


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## CatherineA

johnbeardy said:


> The beauty of importing JPEG originals as DNGs is that it greatly reduces the risk of overwriting the files by editing them in Photoshop. Lightroom edits can also be safely saved back to these DNGs, allowing other applications to see the image's LR-adjusted appearance.



That does sound like a potential advantage. I will need to be further along the learning curve to know how to protect files this way. I’ve only used Photoshop for a few minutes but stilll managed to overwrite and lose two images. I had selected Copy, I think, when I imported those two photos. Won’t go back on PS until I understand a bit more!


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## johnbeardy

When you send a non-raw (raw or dng) image like a JPEG from LR, LR asks if you want to edit the original.  Of course, you don't need to choose that option. But if you do opt to edit the original, that's what PS opens. Potentially, you can then overwrite the original. 

Just play with some test images and see what damage you can do 

John


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## CatherineA

johnbeardy said:


> When you send a non-raw (raw or dng) image like a JPEG from LR, LR asks if you want to edit the original.  Of course, you don't need to choose that option. But if you do opt to edit the original, that's what PS opens. Potentially, you can then overwrite the original.
> 
> Just play with some test images and see what damage you can do
> 
> John



Thanks very much! I guess there are so many things on my screen that I don’t get and just ignore that I ignored that very important question from LR too


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## Victoria Bampton

CatherineA said:


> choose to Copy As DNG or just Copy. I now know that DNG is designed for RAW files but in my case, with JPG, what would the difference be in what is stored with the two ways of copying files?



It's a moot point. Copy as DNG only converts raw files to DNG and does a normal copy for other file types. There are ways of wrapping JPEGs in a DNG wrapper, but not through LR's import dialog.


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## CatherineA

Victoria Bampton said:


> It's a moot point. Copy as DNG only converts raw files to DNG and does a normal copy for other file types. There are ways of wrapping JPEGs in a DNG wrapper, but not through LR's import dialog.



I see! Thank you.


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## clee01l

CatherineA said:


> I now know that DNG is designed for RAW files but in my case, with JPG, what would the difference be in what is stored with the two ways of copying files?


It might be fair to point out that DNG is a file specification that describes the data in the data block.  The data block does not have to be RAW data.   I believe that writing a DNG file out from a JPEG source will simple copy the JPEG data block to the DNG data block.  The header block (container as referenced by others) will contain the metadata translated from the JPEG header block into the DNG header block


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## CatherineA

clee01l said:


> It might be fair to point out that DNG is a file specification that describes the data in the data block.  The data block does not have to be RAW data.   I believe that writing a DNG file out from a JPEG source will simple copy the JPEG data block to the DNG data block.  The header block (container as referenced by others) will contain the metadata translated from the JPEG header block into the DNG header block



Thank you for this information


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