Disabling addition of mandatory tags to new groups?

[amphibian]

Hi! I've had a google and a look-around for mentions of this first

As per the title, I'm wondering of any way to prevent addition of mandatory tags.

I'm testing this by trying to delete all but `Software` in `IFD0` group.

To do this I use `exiftool -all= -tagsfromfile @ -IFD0:Software dst.jpg`, but I see that some mandatory tags (XResolution for example) are added because we create the IFD0 again.
( https://www.exiftool.org/writing.html#Mandatory )

I can delete mandatory tags eg `exiftool -IFD0:XResolution dst.jpg` and the tag is gone from `IFD0` while other tags remain.

Is it possible to run `-tagsfromfile` or other exiftool commands and prevent these mandatory tags from being added when new groups are created? Or is there a simple way to detect which mandatory tags were added and remove them (another operation..) in the same command?

This is the image I am testing with (I've found the entire repo quite helpful, too):
https://raw.githubusercontent.com/ianare/exif-samples/master/jpg/Canon_40D.jpg

[Phil Harvey]

The mandatory tags are added to conform with the EXIF specification.  You are violating the EXIF spec if you don't add them.

But, knowing this, here is the command to do what you asked:

exiftool -all= -tagsfromfile @ -IFD0:Software -xresolution= -yresolution= -resolutionunit= -ycbcrpositioning= dst.jpg

Then you will get this if you try to validate the file:

Code Select Expand

> exiftool -validate -warning -a dst.jpg
Validate                        : 4 Warnings
Warning                         : Missing required JPEG IFD0 tag 0x011a XResolution
Warning                         : Missing required JPEG IFD0 tag 0x011b YResolution
Warning                         : Missing required JPEG IFD0 tag 0x0128 ResolutionUnit
Warning                         : Missing required JPEG IFD0 tag 0x0213 YCbCrPositioning

- Phil

[amphibian]

Thanks Phil! I have a couple more questions but they're outlined very roughly in a couple of notes, and I'd like to reproduce the results before I post. If I can' t figure them out then I'll post here