The search for copyright owners may be simple, or it may be a major detective adventure. For example, an early Philadelphia newspaper merged with a competing paper. The surviving company later went out of business. Its remaining assets including copyrights ended up with an oil company in Jacksonville, Florida. Writing to a newspaper should be easy, but not after several generations of corporate transition.
Journals change names and are sold to different publishing houses.
You need to find the current owner. The original author might have retained the copyright, but the author might now be dead. Copyrights may be devised by the author s will, but few wills specifically mention them. So the copyrights pass to some relative or other beneficiary who may have no idea that he or she has inherited the rights at all. This situation arises often when working with unpublished manuscripts and correspondence.