To DNG or not

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katmandu

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So, after reading Scott Kelby's excellent Lightroom book, I decided to scrap my old Lightroom database and start from scratch. Keyword sets, color ratings, all that good stuff. I also decided to convert all my raw files to dng to improve compatibility. I started with 24'' raw files; re-did the physical directory structure, imported and converted; put off the daunting task of keywording.

But... I also have a little over 1,''' assorted jpg, psd, and tif files: clip art, humorous photos, logos, stuff taken with point-and-shoots that were never raw files. A lot of them are taken from other sources and any copyright belongs to someone else (like the famous "arguing on the internet" poster; who knows where that originally came from). I still want to use Lightroom to catalog these images; I've got this powerful piece of image cataloging software, why not use it?

So... converting these images to dng from the lossy, destructive formats they're in... worth it? And how do I keep them separate from the images I created? Special keyword? Catalog? Color rating?
 
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DNG has it's place, but I'm tending to only use it for raw files (which would have sidecars otherwise), and leaving jpegs etc as their original format to keep them compatible with all programs.

I personally keep a separate keyword - !Raw for all the raw files, !Originals for all other original files (p&s jpegs etc), !Edited for edited images, and so forth. The !puts those keywords at the top of the panel to make them easy to find.
 
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katmandu said:
So, after reading Scott Kelby's excellent Lightroom book, I decided to scrap my old Lightroom database and start from scratch. Keyword sets, color ratings, all that good stuff. I also decided to convert all my raw files to dng to improve compatibility. I started with 24'' raw files; re-did the physical directory structure, imported and converted; put off the daunting task of keywording.

But... I also have a little over 1,''' assorted jpg, psd, and tif files: clip art, humorous photos, logos, stuff taken with point-and-shoots that were never raw files. A lot of them are taken from other sources and any copyright belongs to someone else (like the famous "arguing on the internet" poster; who knows where that originally came from). I still want to use Lightroom to catalog these images; I've got this powerful piece of image cataloging software, why not use it?

So... converting these images to dng from the lossy, destructive formats they're in... worth it? And how do I keep them separate from the images I created? Special keyword? Catalog? Color rating?
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Katmandu, DNG conversion does not apply to the "other" formats, only raw files as DNG is a "raw" format.
OOPs, on checking this I became aware of something I hadn't seen or it was so long ago I'd forgotten!! And that is the options in the Convert to DNG menu, so yes you can convert "other" files to DNG by unchecking the "only convert raw" check box. I don't see any advantage to converting non-raw files though.:roll::roll:

Maybe you could just create a collection for them.
 
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Maybe we are misunderstanding (he and I are roommates, don't hold that against me), but the book suggested that JPGs could be converted to DNG. Is this not accurate?
 
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See my edit !:cheesy::cheesy:
I did check it out again. I think I must have drawn the conclusion (why would I take up more space etc/) about this some time ago. I find it useful to be able to sort by file type at times as well and DNGs only would prevent this.
 
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As I understand it, DNG is like RAW in that it's a (relatively) lossless compression, and any "edits" made to it are reversible. While I realized a long time ago that each save of a jpg results in further compression and eventual degradation of the image (and therefore try to keep a "pristine" copy of any jpgs and only edit duplicates), my impetus for converting was to keep that from happening accidentally (such as when I'm slightly inebriated and feeling witty enough to edit a "lolcat" image, or something similar). Now, granted, it won't be much of a loss to the world if some piece of clip-art gets ratty with jpg artifacts after too many edit/save cycles, but...

I do find it easy to keep my images (ie, raw files that I've taken) separate from the rest of the trash (clipart, etc) just with the file extensions... if I don't want the trash, I just filter out all but DNG. So... would there really be any "archival" advantage to converting the trash? Or more trouble than it's worth?
 
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That's your call Katmandu. When working in LR your "trash" won't get degraded as the changes are recorded in the file header and only applied actually upon export.
Personally I have found no reason to convert at this point in time.
 
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When working in LR your "trash" won't get degraded as the changes are recorded in the file header and only applied actually upon export.
Click to expand...

Even for non-raw formats? That I did not realize, and may change my strategy.
 
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I think that is correct, changes are made in the database and can be written to xmp. I think these are only compatible with ACR/PS at the moment though when written to xmp in the header.
 
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Yep, that sounds right to me too Geoff
 
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Sean McCormack;13' said:
Victoria, as Lightroom use the ! as the NOT operator in Find, surly this is a bad prefix to be using?
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Good point. I didn't even catch this.
 
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Sean McCormack;13' said:
Victoria, as Lightroom use the ! as the NOT operator in Find, surly this is a bad prefix to be using?
Click to expand...

That's an excellent thought Sean. I don't use search very often, I have to admit. Still haven't finished keywording that lot yet! Suggestions for what to change it to?
 
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Thank you guys, I'm off to change my keywords!
 
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I convert all my Canon RAW files to DNG. I found I save about 1MB in filesize per image. That adds up quickly to a real savings. I thought DNG is a loss-less format. Katmandu can you elaborate on your "relatively" comment?
 
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I don't think any compression algorithm is truly lossless; although that assumption is based more on voodoo than mathematical knowledge. Is the compression in DNG truly lossless; ie, when it's uncompressed is the resulting image an exact duplicate of the original in every way? I don't know, so I hedged my bets. It's certainly better than jpeg. :)
 
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katmandu said:
I don't think any compression algorithm is truly lossless; although that assumption is based more on voodoo than mathematical knowledge.
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Voodoo loses out to mathematics in this case -- there is such a thing as lossless compression. I don't know how DNGs are compressed, so I can neither confirm nor deny that DNG compression is lossless, but it is certainly possible.
 
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But isn't the concept of compression lossy? In other words, to compress bits of data, you have to strip out bits of data, right? The compression may not cause damage, but certainly removes something to allow for compression.

...I think. :|
 
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One of the simplest forms of compression is called "run-length encoding". It works like this: If you had a data set that looked like "''''''''''1111111111" (that's ten zeros followed by ten ones), then you could rewrite that as "1' ' 1' 1". That's 4 words instead of 2', no loss.

There are many, many lossless compression algorithms out there, most of them far more sophisticated than this one.
 
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Mark Sirota said:
One of the simplest forms of compression is called "run-length encoding". It works like this: If you had a data set that looked like "''''''''''1111111111" (that's ten zeros followed by ten ones), then you could rewrite that as "1' ' 1' 1". That's 4 words instead of 2', no loss.

There are many, many lossless compression algorithms out there, most of them far more sophisticated than this one.
Click to expand...

Interesting, and that makes sense. Thanks!
 
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