XResolution and YResolution tags not updated when PPI value is changed

[Sebastien Guyader]

When a user wants to change the PPI= value in the Resize module in order to set the printing resolution for the converted images, the XResolution and YResolution EXIF tags are not updated and report the default value 72 PPI.

[agriggio]

I'm not sure bug is the right classification here. The PPI value was never meant to affect metadata.

[Sebastien Guyader]

So I’ml curious, what this PPI setting is used for?

A French ART user ART was surprised that when he set PPI=300 in ART, other software that he uses to put images together (like Scribus) prior to printing still show his edited images as PPI=72, which corresponds to the `*Resolution` EXIF tag values. I think that a number of software read PPI values from the EXIF tags, but I could be wrong. I sent him a command to modify these values with exiftool, we’ll see if it fixes his problem.

Anyways, if this PPI setting in Resize cannot be used eleswhere, I think it should either be “fixed”, of simply removed if you think it's not ART's job to set PPI.

[agriggio]

There's nothing to fix imo, sorry.

If you want to change xresolution/yresolution, you can edit the tags in the metadata tab.

The ppi setting in resize is used to calculate the output size in pixels when you specify the output size in cm or inches (and also to inform you about the max output size in cm/in to get at least the specified ppi).

I hope this clarifies…

[Sebastien Guyader]

Ok, gotcha. No problem. You can close this issue. Thanks for the clarification!

[Sebastien Guyader]

Since the user was interested in applying partial profiles for applying the PPI in batch, I suggested him to add this to his .arp profile:

[Exif]
XResolution=300/1
YResolution=300/1

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