The United States federal government has one very progressive law on copyright. Since 1895 it has not had the legal ability to copyright its own work. The theory is that since everyone has paid taxes for the government there should be no restriction on using what they create. Everyone paid for it, so everyone owns it. All US federal government publications are created in the public domain. (about Public Domain: link.mingpao.com/54044.htm)
There are some exceptions. The Hong Kong Trademark Ordinance, and (in the US) the relevant US law, protect logos and signs from being misrepresented. For example: Even in Hong Kong it is illegal to put the NASA logo on your advertising without permission. Such a use of the NASA logo would suggest that NASA had endorsed your product and would confuse the public. (about Trademarks: link.mingpao.com/54045.htm). Peoples' privacy and national security secrets are covered by other laws. If someone else prepares some material and sells, loans or gives it to the government it can be copyright protected. State and local governments and some independent agencies (such as the post office) are not bound by this copyright limitation, but some have similar laws of their own.
The final exception is that this law is American and it is of course only valid there. Technically they can still claim copyright outside of the US. So is this law useless to us in Hong Kong? Actually it still helps us indirectly. First the US government has never, in over a century, enforced this legal technicality; so one is probably safe. Second since their work is in the public domain locally, many government departments give away their material to anyone. These declarations fall into three categories.
1) There is no copyright notice. It is probably safe to copy these, but not guaranteed.
2) It specifically says that "foreign copyrights may apply". For example the illustrated book Yellowstone's Wildlife in Transition has such a warning. The editor has to be careful, because the book uses other people’s pictures. Do not copy these, without asking permission.
3) A copyright notice specifically declares that their work is in the public domain and does not mention anything about limiting foreign use. Once that has been said, you can use it as much as anyone else. Feel free to copy these legally and safely.
Photographs and imagery on the Marine Corps’ website (at www.marines.mil), just like those on all official military websites, unless otherwise noted, are in the public domain. Attribution of the source is always appreciated by the military photographer.
One may use any pictures on the US Marine Corps’ website, unless it specifically says that there is a copyright on that image. It would be polite to mention the source.
In the next article I will list good sources of safe public domain images and other resources.
Disclaimer: I am not a lawyer and this article is not formal legal advice. It is based on my reading of the HK Copyright Ordinance and Dr. Alice Lee's Intellectual Property in Hong Kong. No guarantee whatsoever is made that the text is legally accurate. Laws can be changed and may have been modified or overturned after this article was written.