Jessica Crabtree

Public domain is the term for media that is totally free for the public to use. If you’re an artist looking for a reference photo to model a painting after, these are the words you want to see.

Previously I said that practically all works are protected by intellectual copyright – and that’s true, but there are a few exceptions. For example:

1. Copyright does not apply to works before 1921. The concept of legal copyright just didn’t exist then. This generally applies to historical photographs, prints in old books, etc. They are considered to be in the public domain – that is, public property.
2. Some works may be in the public domain if their copyright has lapsed (as in the case of the Edward Curtis collection).
3. The creator of the work actually releases his/her work into the public domain. This means they graciously give their work to the public without retaining any rights to it, and anybody can do with it what they wish.

Using pictures from the public domain, however, assumes that you don’t claim rights to the concept – saying you actually came up with the original. So you could sell a painting that includes an image of the Mona Lisa, but I wouldn’t try saying that you were the one who came up with the original idea.

Also, your work doesn’t affect the status of the original, so you can’t restrict others from using it as well. Therefore you can claim copyright only to your version of it. This can mean that any number of individuals may create a painting based on the exact same public domain image – provided they are using the image as their reference, and not each others’ paintings.

http://en.wikipedia.org/wiki/Public_domain