Don't rely on the file's Date Created or Date Modified to store precious metadata about a photo. The photo industry long ago standardized on storing photo metadata inside the file rather than relying on file Date Created or Date Modified. For old photos, use the Metadata > Edit Capture Time command to set the date of a photo, and do Metadata > Save Metadata To File to ensure it is stored inside the file.
See my posts in this thread for more details: Lightroom changes creation date of image files.
Yup, understood. The issue is the old photos . I'll have to go through now manually set the date on tens of thousands of old photos, which while probably something I should have done a while ago, is still a pain.
But I still don't understand why Lightroom would be modifying the Created Date when tagging faces. Modified, sure, as it's writing in new metadata. But this feels like a bug - and worse, a bug that can have serious unintended consequences. Reading through your previous thread, though, it's clearly one that's been around a while!
'll have to go through now manually set the date on tens of thousands of old photos, which while probably something I should have done a while ago, is still a pain.
The Edit Capture Time command has two options that can make this go much faster.
If you have a batch of files whose file Date Modifieds are all correct, then select them all, do Edit Capture Time, select Adjust To A Specified Date and Time, verify that the date/time shown in Corrected Time is the same as Date Modified for the most-selected photo, then click Change All. This will not set all the selected photos to have the same capture date, rather it will set their metatadata capture dates to be their individual file Date Modifieds.
If the file Date Modifieds are not correct but Date Createds are correct, use the same procedure but select the option Change To File Creation Date For Each Image.
Of course, try with a few photos first after making a backup using a backup program you are sure preserves file times correctly.
But I still don't understand why Lightroom would be modifying the Created Date when tagging faces.
When you change any metadata of a pic (including face tags), and you save the metadata back to the file (either manually using Metadata > Save Metadata To File or automatically via the preference Catalog Settings > Automatically Write Changes Into XMP), LR creates a copy of the original file with the new metadata, deletes the old file, and renames the copy to the original name (a standard approach of many applications to ensure that if the program crashes while writing the file, you're not left with a half-overwritten original). This has the effect of assigning new file Date Created and Date Modified times.
See the posts I linked to above about why this behavior is not clearly a bug and why photo software cannot rely on the file Date Created to store the capture time or digitization time of a photo.
I think you are talking about two different things. The Create date original and digitized shown in LR is always when the image was taken. That doesn't change. What you are looking at is how the File System see the date and time of when the file was placed on the drive and the last time it was accessed and or changed. But the actual Create date and time stays the same.
If these are old photos you scanned then you may be right as there is no real Capture time associated with those files.
I think you are talking about two different things.
No, ianbnet and I are both referring to the operating system's file Date Created and Date Modified, not metadata dates stored within the file. Ianbnet wrote:
Lightroom resets the created by, modified by and last accessed dates on the file to the current date!
I doubt if LR can change the OS's file created, modified, accessed? Surely it is the OS that does this each time it sees a file change. These dates apply to all files on your computer, not just images. In any case, these OS dates are rather flaky, so no point in using them for anything other than backup up files.
The image capture date, digitised date, and modified date are store in the image file in the Exif part of the metadata. Originally created by the camera, they can be altered by software afterwards in necessary. I'm having to do that with thousands of old transparencies that have been scanned or rephotographed. Tedious!
I doubt if LR can change the OS's file created, modified, accessed? Surely it is the OS that does this each time it sees a file change
On both Mac and Windows, applications can explicitly change the file dates. On Windows, the low-level OS copy-file call will change the creation date, but an application can set it back. On Mac, I'm not sure what the low-level OS calls do, but it appears that higher-level library copy-file calls will preserve creation dates.
OK, I've always assumed that the OS file-system saw the file changes made by a program and altered the dates accordingly. But I don't have knowledge of the detailed innards of the OS/program relationship.
I've always assumed that the OS file-system saw the file changes made by a program and altered the dates accordingly.
Yup, the OSes do that. But applications can explicitly change the dates also. Photoshop and Bridge do that (change file Date Created) on Windows when they modify a file.