Originally posted by OldNoob really educational thread. I always thought that the editing was done on a temporary file copy and that the "Save As" protected the original ,, but now i am learning that is not the case.
Also,, be careful using Picasa to convert raw files ,, it edits EXIF and gives itself ownership of the image.
Yes, Picasa is dangerous. It even was modifying EXIF data in my write-protected JPG files. This ignorance of read-only files is a clear no-go for any software.
This happened with Picasa software about one year ago. I left Picasa immediately because of this, but I do not know if this behavior has improved since then.
LR, C1, ... and other good tools respect read-only DNG, JPG, PNG, ... files, but most of these tools are not able to use (read or create) XMP sidecar in this case.
Originally posted by Canada_Rockies It depends entirely on the program you are using. Adobe Photoshop Creative Suite modifies the image, Adobe Lightroom doesn't, for example.
A little bit unclear for. Which file format and which modifications (image, meta data) do you mean please?
Of course with PhotoShop you can overwrite any original file completely with the edited image. With non-destructive LightRoom you do not overwrite the original image, only the embedded DNG metadata and/or the embedded DNG preview image can be overwritten. The export from LightRoom is of course something else, because here you can deliberately overwrite existing files.
Originally posted by Class A Peter, you seem to be happy with the catalogue being the main container of information.
So why do you not just turn off automatic writing of metadata to image files and then never execute a manual "save"?
Does this not leave your DNG files alone?
Many people prefer to have an additional backup of the metadata in either XMP files or in DNG files, but if you can live without that additional backup and do not need other software to see the LR metadata then my suggestion should work for you.
Thank you, that is a Class A understanding of my original issue and that is exactly the good solution with LightRoom. But I have to manage my DNGs also with other tools good tools (ExifTool, ExifTool-based SW, Imatch, ...) and I need to share ratings, labels, keywords, categories among them and Lightroom. With non-DNG raw files this works perfect through XMP sidecars, but with DNG apparently not at all. That was the reason for my original posting and the unrealistic "back-conversion" request.
Seems, that the only solution for a good workflow is to define one read-only master DNG and a slave writable DNG copy. But this doubles the required hard disk and backup space and increases the backup time dramatically. The additional files make the total number of files in LightRoom, DAM and file manager larger than necessary. Workarounds to circumvent some of the issues are are for sure possible, but they make the backup procedures, version management and DAM more complex.
Peter