jpegs and DNG questions

  • Thread starter Thread starter frank10
  • Start date Start date
Status
Not open for further replies.
F

frank10

Guest
Can jpegs be converted to dng files? Is there any lossy compression performed in the process? Will lightroom store changes in the dng file or in it's catalog or both?
 
Sort by date Sort by votes
Jpegs can be made into DNG's. though I don't know why you would want to. I seem to remember the DNG was a much larger file and you don't gain any of the raw/dng benefits when developing, AFAIK.

You could try a couple and find out for your self.

Yes, the metadata is always saved in the Catalog but you can opt to auto save it in the dng file or use Cmd/Ctl-s to save for selected files.

Don
 
Upvote 0 Downvote
Don,

The benefit would be having the metadata in the one file instead of separate. I tried a couple and it really increases the file size.

My wife likes to view our photos with Picasa. It handles DNG files nicely, but I don't know if it picks up on the separate meta data files
 
Upvote 0 Downvote
Frank, I'm confused. In general, jpeg metadata is contained in the jpeg file. How are you encountering metadata in a separate file?

I understand your practical problems in sharing the family piece of your LR workflow with the family. I was using the DNG route to share processed images with non-Adobe apps, so the neophytes in the household could access them. Unfortunately the capture date bug with DNG conversion/import has put that on hold for the time being.

In the meantime, I'm still not sure I understand where your separate metadata file is coming from, for jpegs.
 
Upvote 0 Downvote
I'm not explaining it well.

I understand that lightroom stores image adjustments with the dng file while leaving the core image unmodified. it does this also with jpgs? Maybe the confusion is that I'm calling image adjustments metadata.

my end goal is to have non lightroom users be able to see "corrected" versions of the images.
 
Upvote 0 Downvote
Aaah. I see.
I understand that lightroom stores image adjustments with the dng file while leaving the core image unmodified.
Click to expand...
Yes, and some of the data it stores is a preview image which can be extracted by DNG aware software, that's what you're seeing in Picasa.

it does this also with jpgs?
Click to expand...
When you import jpegs, here's what happens. Any adjustment data (development, and other metadata like keywords) is stored in the LR catalog, the jpeg pixel data are not touched. In addition, you can ask LR to store the both the adjustments and/or the other metadata, in a special location within the jpeg file. This also does not touch the pixel data. Unfortunately, only LR and Adobe Camera Raw know how to handle that data, so any other graphic program will see the original unedited jpeg image.

As you note, you can convert that JPG to DNG, you can enable the same metadata embedding, and with this file type, you get an embedded preview, so other DNG software can display it. In my experiment, however the file size was twelves time larger, again as you noted.

The last option is to just export the adjusted jpeg for your wife to view. This has the 'pro' of being way smaller than the DNG conversion. It has the 'con' of going back to tracking 2 files.

As I noted in my first post, like you, I've been struggling with this dedicated LR workflow, family image sharing dilemma, since I started with LR. Like you, I think the current solution is DNGs. I work strictly with raws, so the DNG conversion actually produces slightly smaller files, so this is a win -win. (Temporary glitch with capture-time file naming).

Those are the fundamental trade-offs, that I see. You'll have to evaluate your individual priorities.
 
Upvote 0 Downvote
Great answer Brad!
 
Upvote 0 Downvote
Brad,

Thanks for the explanation. The increase in file size isn't going to work. I'm shooting in RAW going forward so the DNG format will work well for those file.

I have 1' years of jpeg photos that I need to organize. It would be nice to use DNG if it somehow maintained the original jpeg and kept the filesize small.

I wish I could go back in time a few months and switch my camera format from jpg to RAW. I had a family event where I set the white balance wrong and the images aren't that great.

Victoria,

I'm enjoying your lightroom book!
 
Upvote 0 Downvote
This doesn't help Frank unless some of his older photos are tiff but tiff to dng comes down from, for example, a 14 meg image to a dng of 8 meg.
I am fairly sure I read somewhere that the conversion of jpeg to dng was 'being looked at' by Adobe in terms of the file-size increase in that, I believe the size increase is due to storing a tiff version of the jpeg within the dng.
[Note - I have found the source of my info above - from another LR2 site far less authoritative than this one;)]
 
Upvote 0 Downvote
Frank, I'm very glad to hear it!
 
Upvote 0 Downvote
Status
Not open for further replies.
Back
Top