Copyright does not last forever. The main purpose of copyright law is to allow for creators of works to be reasonably rewarded for their creative efforts. How long it lasts depends on which country you are in. In Canada, copyright generally lasts for the life of the author, plus 50 years (i.e., the "life plus 50" rule). By contrast, in the U.S. and Europe, copyright generally lasts for the life of the author plus 70 years, though it can differ depending on factors such as the type of work, the manner of publication and the date of creation. Use of a work in Canada is governed by the Canadian rules for the duration of copyright protection.
For example, in Canada, if a work is created on April 30, 1999, and the author dies on July 27, 2035, then copyright protection extends from April 30, 1999 to December 31, 2085. If the work was created by more than one person, copyright protection exists for the life of the creator who dies last, the remainder of the calendar year in which that person dies, plus 50 additional years. Some types of works such as sound recordings and some photographs and films may have a different length of copyright term. Both economic rights and moral rights subsist for the same period of time.
After copyright expires, a work becomes part of the public domain and may be freely copied and distributed. However, do not assume that works are in the public domain.
Federal and provincial government documents are under Crown copyright. Crown copyright lasts for 50 years after the date of publication. Therefore, a government document published in 1998 is under crown copyright until December 31, 2048. More information on using federal government materials that are still under crown copyright can be found at About Crown Copyright.