jpg quality after keyword and lightroom

bphillips330 · 5th of June 2007 (Tue)

If I add key words or add a collection and the metadeta is eddited on a jpg picture. Does the quality degrade. I know everytime you open a jpg file and then resave it (if eddited) then there is a slight degredation as it is a lossless file format. If i add a key word to a jpg, does that then "resave that file" and compress even more.

Can i convert a jpg to .dng format and then it does not become lossless or is .dng only for raw files?

In2Photos · 5th of June 2007 (Tue)

It does not degrade the quality.

Yes you can convert the jpegs to DNG, but since LR does non-destructive edits it really doen't matter, especially since both file formats are handled the same way with regards to edits.

Anke · 5th of June 2007 (Tue)

No, the keywording will either be saved in Lightrooms database or an external XML file depending on how you've set LR up.

In2Photos · 5th of June 2007 (Tue)

Quote:

Originally Posted by Anke

No, the keywording will either be saved in Lightrooms database or an external XML file depending on how you've set LR up.

Only for RAW files. All others will have the edits written directly to the file (JPEG, DNG, TIFF, PSD).

davidcrebelxt · 5th of June 2007 (Tue)

Quote:

Originally Posted by In2Photos

Only for RAW files. All others will have the edits written directly to the file (JPEG, DNG, TIFF, PSD).

Either way, as In2Photos said, it does not degrade quality... that metadata is put before or after image data ( I can't remember which) and the pixel data is shifted (unchanged) accordingly... no recompression of the image data.

Anke · 5th of June 2007 (Tue)

Quote:

Originally Posted by In2Photos

Only for RAW files. All others will have the edits written directly to the file (JPEG, DNG, TIFF, PSD).

Blimey, I stand corrected, I thought it was for all

In2Photos · 5th of June 2007 (Tue)

Quote:

Originally Posted by Anke

Blimey, I stand corrected, I thought it was for all

I did as well. I just got Kelby's book and this is in the second chapter. I was a bit shocked.

droiby · 5th of June 2007 (Tue)

Quote:

Originally Posted by bphillips330

If I add key words or add a collection and the metadeta is eddited on a jpg picture. Does the quality degrade. I know everytime you open a jpg file and then resave it (if eddited) then there is a slight degredation as it is a lossless file format. If i add a key word to a jpg, does that then "resave that file" and compress even more.

Did you mean lossy file format?

Anyway, provided you're editting the EXIF information and not image data, there will be no loss in image quality.

Quote:

Can i convert a jpg to .dng format and then it does not become lossless or is .dng only for raw files?

Sure you can, but you've already lost information in going to jpg in the first place. It just means that subsequent edits will not lose you more data.

5th of June 2007 (Tue)	#1
bphillips330 Member Join Date: Oct 2006 Location: ohio Posts: 612 IMAGE EDITING OK	jpg quality after keyword and lightroom If I add key words or add a collection and the metadeta is eddited on a jpg picture. Does the quality degrade. I know everytime you open a jpg file and then resave it (if eddited) then there is a slight degredation as it is a lossless file format. If i add a key word to a jpg, does that then "resave that file" and compress even more. Can i convert a jpg to .dng format and then it does not become lossless or is .dng only for raw files? __________________ Body : 50D and 400/xti + grip Lenses: 50mm 1.8 II / Tamron 17-50 f 2.8 / kit len / 70-200 f2.8L IS!!!! / Canon 1.4 TC II / Sigma 70-300mm dl Macro super Flash: 580 exII A whole bunch of other goodies.

5th of June 2007 (Tue)	#2
In2Photos Moderator, Archive Keeper Join Date: Dec 2005 Location: Near Charlotte, NC. Posts: 19,808 IMAGE EDITING OK	Re: jpg quality after keyword and lightroom It does not degrade the quality. Yes you can convert the jpegs to DNG, but since LR does non-destructive edits it really doen't matter, especially since both file formats are handled the same way with regards to edits. __________________ Mike, The Keeper of the Archive Current Gear and Feedback \| My Pbase Gallery \| mdsportsphoto.com

5th of June 2007 (Tue)	#3
Anke "that rump shot is just adorable" UK SE Photographer of the Year 2009 Join Date: Oct 2006 Location: Royal Tunbridge Wells, UK Posts: 30,148 IMAGE EDITING OK	Re: jpg quality after keyword and lightroom No, the keywording will either be saved in Lightrooms database or an external XML file depending on how you've set LR up. __________________ Anke 1D Mark IV \| 16-35L II \| 24-70 f/2.8 II \| 70-200L f/2.8 II \| 100L Macro \| 50 f/1.4 \| 580EX II Join the Official POTN UK South-East Thread \| Follow me on Twitter \| Tunbridge Wells \| Flickr

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