I would not use this as a "key" field. you'll need it to keep your users happy and to support a "legacy" system of labeling inventory, but don't use the field a primary key for use in relationships. Just store this value in a field in the Artwork table so that it can be used for labels, searches and sorts.
That said, this demo file shows how to generate different number sequences for different sub groups of records in a table: https://www.dropbox.com/s/ggjy88cgkescopy/CategorySerialNos.fp7
It's in the older file format so users with FileMaker 12 or newer will need to use Open from FileMaker's File menu to produce and open a copy of this file converted to the newer file format.
98% of the time, the best option is a number field set up to auto-enter a serial number each time a record is created in that table. Sometimes--especially if you use iOS devices each with a separate copy of the database, it makes more sense to use a text field with Get ( UUID ) as the auto-entered ID value.
Such a field is called a "Primary Key" and should be the most often used field to match to records in related tables.
The ideal primary key is:
1) always unique
2) never, ever changed once assigned to a new record
3) devoid of any additional "encoded meaning"
4) have values assigned via the most simple and bullet proof fashion possible.
The IDs like those you've mentioned in this thread fail criteria 3 and 4.