I want to write Keywords to my pictures but I seem to be unable to write IPTC:Keywords although XMP:Keywords are fine. I get the following for all IPTC entries
Cannot Be Edited
Format: heic
Source: iPhone 8/XR
Why are all IPTC entries read only? It seems to be limited to heic pictures.
On a second note, is it a good idea to try and write the keywords to both metadata standards? Is one sufficient and if so which one. I want to write to both to increase visibility in different apps.
Might just have answered my own question. Making a big assumption that you are using ExifTools, I found out that it cannot write IPTC entries in heic files as per table.
The application uses ExifTool (made by Phil Harvey) and CoreImage (made by Apple). Both engines do not support IPTC at the moment.
As said in this forum (https://www.lightroomqueen.com/community/threads/keywords-with-heic-vs-others.42495/), HEIC is a proprietary format made by Apple. Even if the format officially supports IPTC metadata on Wikipedia, Apple does not support IPTC metadata in its engine. Some solutions are to use an equivalent tag, use a sidecar file, or/and a JPEG alternative.
As XMP is a modern extension of IPTC, I encourage you to use XMP:Keywords instead of IPTC:Keywords.