How do I modify TIFF physical resolution metadata

Question

I have several pyramidal, tiled TIFF images that were converted from a different format. The converter program wrote incorrect data to the XResolution and YResolution TIFF metadata. How can I modify these fields?

tiff.ResolutionUnit: 'centimeter'
tiff.XResolution: '0.34703996762331574'
tiff.YResolution: '0.34704136833246829'

Ideally I would like to use Python or a command-line tool.

Answer 1

One can use tifftools.tiff_set from Tiff Tools.

import tifftools

tifftools.tiff_set(
    PATH_TO_ORIG_IMAGE,
    PATH_TO_NEW_IMAGE,
    overwrite=False,
    setlist=[
        (
            tifftools.Tag.RESOLUTIONUNIT,
            tifftools.constants.ResolutionUnit.CENTIMETER.value,
        ),
        (tifftools.Tag.XRESOLUTION, xresolution),
        (tifftools.Tag.YRESOLUTION, yresolution),
    ],
)

Replace xresolution and yresolution with the desired values. These values must be floats. In this example, the resolution unit is centimeter.

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This is also possible with the excellent tifffile package. In fact there is an example of this use case in the README.

with TiffFile('temp.tif', mode='r+') as tif:
    _ = tif.pages[0].tags['XResolution'].overwrite((96000, 1000))

Be aware that this will overwrite the original image. If this is not desired, make a copy of the image first and then overwrite the tags.