IIRC, this also applies to photographers. It becomes a real pain when trying to put together a collection of old family photographs for a family album. If the photo has any semblance to a studio photo or a work for hire, you are supposed to track down the date of creation, original studio, and try to get permission from that studio (or heirs) for copying. My wife did this a few years back, and the magic year was 1923 (or thereabouts).

I have even heard stories of Old Mrs. Jones bringing in a war photo of her Jonny, asking to have a copy of it made, and actually having it be a sting operation of sorts (this was told me by a Kinkos employee, scale the accuracy attribute as you will).