Licensor URL: the link to where an image can be licensed

Licensor URL holds the address of a page where someone can obtain a license for the image: a checkout page, a price list, a contact form. Google Images uses it for the "Get this image on" link next to licensable results. The badge itself depends on a different field, the Web Statement of Rights.

A field inside a structure

It is not a flat tag. IPTC defines Licensor as a PLUS structure (plus:Licensor, namespace http://ns.useplus.org/ldf/xmp/1.0/) holding a name, an ID, postal address, phone numbers, email and URL, with up to three licensors per image. LicensorURL is one field of one entry. Google's documentation insists on this: the URL must be a property of a Licensor object, not of the image, so a hand-written packet with a bare top-level plus:LicensorURL does not qualify.

ExifTool flattens the structure so you can write the field directly. -struct shows what is really stored:

exiftool -XMP-plus:LicensorURL="https://example.com/buy/1234" photo.jpg
exiftool -G1 -s -struct -XMP-plus:Licensor photo.jpg

[XMP-plus]      Licensor                        : [{LicensorURL=https://example.com/buy/1234}]

With -G the flattened tag prints as [XMP] LicensorURL.

The multi-licensor trap

Flattening hides which value belongs to which entry. After adding a second licensor (Doe Studio, with its own URL), the flat view reads:

[XMP-plus]      LicensorURL                     : https://example.com/buy/1234, https://example.org/license
[XMP-plus]      LicensorName                    : Doe Studio

Nothing there says Doe Studio is the second entry. Worse, writing -XMP-plus:LicensorURL= on that file replaced the list: the first entry got the new URL and the second lost its URL entirely, leaving {LicensorName=Doe Studio}. With more than one licensor, read with -struct and write whole structures, for example -XMP-plus:Licensor+={LicensorName=Doe Studio,LicensorURL=https://example.org/license}.

Without the command line

Our metadata editor has a Licensor URL field for JPEG and TIFF files. The XMP packet is the same in both; a TIFF keeps it in tag 0x02BC instead of an APP1 segment. In Lightroom Classic the field sits in the IPTC Extension panel under Licensor, URL. For the other rights fields, see the copyright guide.