In the US, greeting cards and postcards published previous to 1923 that do not contain a valid trademark are in the public domain. From 1923 to 1978, greeting cards and postcards that do not have a valid copyright notice (C or Copr or Copyright) are in the public domain if the failure to provide copyright notice was not rectified within a short time frame after publication and there is no trademark (1909 Copyright Act).  During that same time (1923-1978), greeting cards whose copyright expired are in the public domain if the copyright  has not been renewed and there is no valid trademark. After 1978, the laws changed, protecting pretty much everything that was original for a long, long time, with or without a copyright notice. Copyright laws may be different in countries outside the US.

Mechanical or rote digital reproduction of public domain images does not create any new rights to that image according to US law as established by precedent on the federal district court level. Interpreted, that means scanning an image or copying an image does not give an individual, corporate or public body a new copyright. (Bridgeman Art Library v. Corel Corp., 36 F. Supp. 2d 191 (S.D.N.Y. 1999)

For a more detailed discussion go to www.publicdomainsherpa.com.

For a handy copyright calculator, click here.