Model and property releases are required whenever an image is sold for commercial use. This includes any image that is offered to market using a Royalty Free license. It is not any particular type of image that needs such a release, it is the use that the image is put to. So if you anticipate commercial use at any point, you need to take steps to obtain the correct releases at the time the photo is being taken.
A model release is a legal document giving you permission to use someone's image for commercial use. This includes anyone who appears in one of your photographs and is recognizable in any way. Usually that would mean that their face is included, but it may also be a recognizable silhouette of someone or their hands if you are using a hand model.
Model releases are not just required when you are using the services of professional models, but anyone who may appear in the picture and your intension is to use the image for commercial use. So it is always useful to have a book of model release forms on you when you are out photographing. Because of the difficulty of walking up to someone you have just captured without them knowing and asking them to sign a model release form, modeled release images tend not to be candid shots, but are usually set up shoots.
You do not need a model release for images that are only intended for editorial use. Editorial use has special protection under the copyright laws of most countries because it is seen as serving society in terms of the right to learning and information. If someone is in a public space, therefore, you can photograph them and publish the photograph without needing to secure a model release, as long as the use is editorial. As soon as you want to use the image for commercial use, however, you need to have the release on hand.
Model releases need to be signed by the person. If the photograph and if the person is a minor, then you will need the signature of the parent or guardian.
Figure 1 An example of a model release form. This is one that Africa Media Online supplies to contributing photographers
Property releases are required when you want to use a photograph of anything that is privately owned for commercial purposes. This may be buildings and land, but it may also be animals or an object that is identified with a person. Property releases are also required if your photograph includes a trade mark or an insignia. Animals photographed in zoos also require model releases for commercial use, but wildlife do not.
Again, the only requirement for a property release is if you want to use the image for commercial use. Editorial use does not require a property release. That is not to say you always have permission to take photographs. If you are on private property or even government property you may be prevented from taking photographs under the regulations governing that property. If, however, you take a photograph of that same property from a public place, the property owner is unlikely to be able to stop you from publishing that image for editorial use. If you do not have a property release, however, he could stop you using it for commercial use unless his property simply formed one part of an overall scene such as a city skyline.
In many countries the requirement for property releases is rare. In a highly legislative environment like the US or the UK, however, it has become common. When there is money to be made, you can be sure it will make its appearance. In South Africa, for instance, the requirement was rare until the FIFA World Cup came to the nation in 2010. Suddenly all the stadiums required the signing of property release forms in order to take pictures of the stadia. Although they could not stop photographers from taking pictures for editorial use, for commercial use they could require it. One stadium attempted to get photographers to sign a property release contract that would not only require them to pay a fee and gain a property release for the image for which they were applying, but also for any other image that the photographer has ever taken or will ever take of that stadium in her lifetime. Signing such a contract effectively shuts down all editorial use you may want to make of your images. So be careful when signing property release contracts presented to you by property owners! It is better if you are the one to come up with the contract.
Copyright clearance is another type of release. It is required if you are taking a picture of a copyrighted work, such as a painting, a sculpture or a photograph, where such works represent the main subject of your photograph. If this is the case you would need copyright clearance to publish that photograph whether for commercial or editorial use. This is because your photograph of someone else's creative work does not represent an original work by you, therefore it does not meet the conditions to be protected under copyright law. So, if you do want to be able to publish such a photograph, you would need to gain copyright clearance from the author of the original work or its custodian. Again, this needs to be a signed legal document that you can produce if there is ever a query.
Photographs of logos, brands and trademarks would also fall into this category. These are considered to be owned by the organization who had them created, and simply photographing them does not transfer ownership of the copyright to you. You would need copyright clearance in order to publish the photograph whether for commercial or editorial purposes. If, however, a logo or a brand forms part of a wider scene in your photograph, then the work is considered your original work and therefore protected under copyright. If that is the case, you can use the image for editorial use without permission. For commercial use, however, you need a property release.
Alamy has published a useful guide to what kind of images need model, property releases and copyright clearance.
The ASMP has an in-depth Releases Tutorial with example releases. Although specifically geared to US law, it still provides valuable information.