Painting tall  buildings requires scaffolding carefully built for the safety of the painters -- unless the painters are drones.

Drones, unmanned aircraft, are known for their work in military situations, and for their use with cameras in aerial photography and search and rescue missions. But at least one company is trying them out with paint spraying. These drones are able to spray paint evenly onto surfaces, their makers say, and can handle buildings up to three stories tall.

They may be most useful for painting ships in dry dock, actually. Their manufacturers also look forward to a time when they can paint skyscrapers, keeping human painters out of harm's way.

In theory, the drone painters could eventually take on the responsibility for painting surfaces that are difficult or dangerous for humans to access. Their makers hope that this kind of drone could provide a smooth coat of paint without the time and expense of scaffolding. They describe the paint-carrying drones as having a sort of umbilical cord to carry paint. This naturally limits their current flexibility.

Will they be able to do the job? Perhaps. Surface preparation would require specialized sensors and advanced control. Factors like temperature, humidity, and the history of the surface -- paint, exposure to elements of chemicals and the like -- must all be taken into account in order to produce a lasting paint finish.

And certainly fine work with architectural details and multiple colours would be out of the range of painting drones. Ships and skyscrapers, which are less likely to have any gingerbread or special details around windows or rooflines, may be a better canvas for drone painters than residential buildings.

You will be better off with skilled human painters working with your home's special details. And scaffolding is still a must for safety's sake. But robots have taken over many tasks that humans used to do, and have spared people from dangerous occupations. We'll be watching this new painting technology with interest.