Converting JPGs to DNG... Thoughts?

[EdMacke]

I don't want to start yet another debate on the viability and advantages of DNG vs. RAW. Been there, done that, and I've decided to use DNG!

But having made that decision, I'm now wondering about the advantages / disadvantages of converting non-RAW formats to DNG, as well.

It seems like there might be subtle hints on Adobe's part that DNG isn't meant for JPGs: LR's DNG conversion dialog has the default set to only convert RAW images, and the standalone DNG converter doesn't even offer the option of converting JPGs.

However, the OCD side of me likes having all my images - whether from my Nikon DSLR (RAW), my wife's Kodak P&S (JPG only), or my scanner (usually TIFF) - in one format: DNG. Plus, hey, if DNG is good enough to be the "digital negative" for RAW, why not for JPG, too?

Are there any advantages to converting JPGs to DNG beyond my fulfilling my OCD tendencies?

Are there any *disadvantages*?

Note that I'm only talking here about for use as "master images" within LR. I always export my final images to a derivative folder in JPG format to bake in my edits, keywords, etc.

 

[Victoria Bampton]

Advantages - well, it allows you to update the preview without baking it into the original data, but that's about it.

Disadvantages - jpeg is a universal format, dng not quite yet, and the dng's will be bigger than the jpegs.

I'm all for DNG for raw files - but for jpegs, I'd stick with jpeg. YMMV.

 

[EdMacke]

Victoria,

Thanks for the quick response and insight.

Yeah, the previews is actually kind of what prompted me down this path: when looking at the images in Windows Explorer the thumbnails did not include any of my edits. At first, I panicked, thinking my edits had been lost. Ack!

Then, through some Googling and noodling, I came to realize that LR was doing for JPG what it does for RAW/DNG - the original image remains unchanged and edits are in the catalog and (optionally) in the JPG itself. However, unlike DNG, the edits aren't included in the preview used by Windows. Or, at least I think that's what's going on.

So I liked having the previews be "correct" and I liked having my files in one format, hence my thoughts about converting to DNG.

Re: Universal format: That's not really so much of an issue - I only use DNGs as my archival storage format (for using LR with my "master images"). As I mentioned, when I'm finished tweaking, I export every image in JPG format specifically because I can use it anywhere then.

Thanks again!

 

[clee01l]

While I wish I had all my master originals in DNG, I don't think it is important when there is no 12-14 bit RAW file to begin with. Part of the DNG Standard includes embeddding a JPEG inside. So if you convert JPEGs to DNG, in effect all you are doing is putting a DNG/TIFF6 wrapper around your JPEG along with maybe a second copy of the JPEG. Lightroom will write the EXIF data along with any XMP section filter settings back to the original JPEG, just like it does with an original DNG. You don't really gain anything by converting the JPEG to DNG.

 

[EdMacke]

You don't really gain anything by converting the JPEG to DNG.

Well, there is one advantage: getting previews that include my LR edits.

So is that one feature is worth the larger disk space required by the DNG files? Dunno - now I'm curious what the file size difference would be. Maybe a 1'% increase would be worth it, but if it's 1''% larger that's another story!

I guess the good news is that - other than disk space - you don't really lose anything by converting, either.

Thanks again for all the input - at least now I can make an informed decision!