Hi, I have been reviewing the metadata in my SilverFast DNG files. I noticed that the IFD0:ModifyDate is in an unexpected format. Should I be concerned? I reached out to SilverFast, but they didn't have any answers. Thanks.
[IFD0] ModifyDate : 17.09.2024 09:25:07
Yeah, that probably needs to be fixed. Is it just ModifyDate or other the other date/time tags affected as well?
Try this. Test it first to make sure it works.
exiftool "-ModifyDate<${ModifyDate;s/^(\d\d)\.(\d\d).(\d{4})/$3:$2:$1/}" /path/to/files/
Example:
C:\>exiftool -G1 -a -s -ModifyDate y:\!temp\Test4.jpg
[IFD0] ModifyDate : 17.09.2024 09:25:07
C:\>exiftool -P -overwrite_original "-ModifyDate<${ModifyDate;s/^(\d\d)\.(\d\d).(\d{4})/$3:$2:$1/}" y:\!temp\Test4.jpg
1 image files updated
C:\>exiftool -G1 -a -s -ModifyDate y:\!temp\Test4.jpg
[IFD0] ModifyDate : 2024:09:17 09:25:07
Thanks. I'll test it when I have some free time later today and let you know.
SilverFast automatically adds IFD0:ModifyDate. SilverFast only enables a user to add IPTC:DateCreated, IPTC:TimeCreated. All dates/times, including System File Dates and Composite dates, are in the correct format. Only the ModifyDate is in an incorrect format.
I typed: exiftool "-ModifyDate<${ModifyDate;s/^(\d\d)\.(\d\d).(\d{4})/$3:$2:$1/}" ~/Test/sample.dng
The result: zsh: bad substitution.
According to SilverFast, ModifyDate has been in this format for at least 9 years. SilverFast is changing the DNG filter next year, but no guarantee this ModifyDate issue will be resolved.
Use single quotes instead of double quotes in zsh to avoid the shell interpolating the $-variables (see my signature).
I'm surprised that SilverFast could screw up the date so badly for so long.
- Phil
Thanks Phil. Single quotes worked. I'm surprised as well. It would have failed the most basic test case. Even more surprising, there doesn't seem to be an urgency to fix it.
Love ExifTool. Thanks so much for this lifesaver of a tool!
Btw, what changes cause the IFD0:ModifyDate to change? In my DNG files, the IFD0:ModifyDate reflects the date the image was scanned. I edited my DNG files using SilverFast, but the IFD0:ModifyDate didn't change, likely because SilverFast edits of DNG files are non-destructive. Using ExifTool, I added IPTC:DateCreated (later than the IFD0:ModifyDate) and IPTC:TimeCreated values to the DNG files, but that didn't change IFD0:ModifyDate either. I didn't expect that it would accept a Create Date later than the Modify Date. Perhaps SilverFast never expects the IFD0:ModifyDate to change which could explain why correcting the format wasn't a priority for SilverFast.
IFD0 ModifyDate should be changed whenever the file is modified. ExifTool doesn't do this because it gives you the power to do what you feel is best.
- Phil
Thanks. Good to know. I tested the ModifyDate in SilverFast, both in its original format and in the corrected format. When I edited the image, the ModifyDate didn't change in either instance. I'll ask SilverFast if SilverFast expects it to change.
A lot of programs don't change the ModifyDate. But I've seen better programs update the XMP:MetadataDate tag if the only change is the metadata.
SilverFast populates the ModifyDate when a file is generated from a scan and when subsequent files are created from the original scan. Non-destructive changes to DNG files don't change the ModifyDate. SilverFast doesn't generate an XMP:MetadataDate value.