Is there any reason to covert JPEGs or TIFFs to DNG?

[peterkrogh]

Valeria,
>Develop TIFF and JPEG files in LR is exactly the same then developing DNG?

The file developed as a TIFF or the same file saved as DNG will look the same with the same settings applied.  No advantage there.

>Or DNG has any self advantage to be developed in LR? If there is not, I can convert both TIFF and JPEG to DNG only when I export files, after having developed them?

While this is true, this sounds backwards to me.

DNG may be a better file for archive, if all your work is done in Lightroom.  I would consider TIFF and JPEG to be better formats for output and interchange.  HWy convert to DNG on output?

>I mean, while I don't save JPEG (that occurs during the exportation) there is no destruction, right? 
Right, Lightroom will not alter your JPEG destructively.  It will only add metadata.
Peter

[Valeria Lages]

      Peter,

      As I do with RAW, I want to keep my old original files from camera and scanner, that's why I will convert to DNG only when exporting them.

      If there is no difference edit JPEG and TIFF or converted DNG files in LR, I will still my actual workflow: I import to LR to rename and apply general metadata, keywords, caption, sort and rate. Then I export twice the files:  1) "as original" to my "original cam/scan" folder and 2) "as dng" to "original dng" folder. After this I re-import DNGs and these will be the files I will work from this moment on.

      If I need I have the original files from camera and scanner. We never know what technology and software can offer in the future and having the hardware native files can be a good chance for something new.

     About JPEGs: if I apply only metadata (keywords, IPTC fields and rating), without develop, am I destroying it while exporting "as original"? Each time I export/save JPEG I am destroying it, no matter if I have only applied metadata or destruction occurs only if I have made changes in the picture (colors, levels etc)?
   
     If this metadata I initially apply doesn't damage the file, I will keep JPEG as "original" because it is smaller than DNG. And then I re-import the "original_DNG" (from the second exportation) to develop and apply specif metadata. But if the firts exportation (only metadatada applied) will destroy the file, I will consider export first as TIFF (that is more universal than DNG) and second as DNG.

      Does it make any sense? 

      Thanks,

       Valeria