X-ray image of a 'Baby Annabelle' doll
X-radiography is an imaging method that uses high energy radiation (X-rays) to reveal the structure of an object based on the different densities of its constituent materials. Higher density materials such as bone or metal absorb more X-rays than lower density materials such as wood or soft tissue.
X-radiography in the study of oil paintings
X-rays have been widely used in the study of oil paintings, and can sometimes show us changes that have been made to a painting by the artist. They can also reveal structural information or the location of old damages, which might be hidden under later restoration when viewed in ordinary light.
X-radiography in archaeology
In archaeology, X-radiography is a routine method for investigating excavated metalwork, and can reveal structures hidden in corrosion layers. X-radiographs can often reveal information about how a toy has been made, the weave of a textile object, or the type of inclusions in the clay of a ceramic object, and there are many more examples. X-radiography gives us a picture of hidden details, without the need to take any samples - it is a completely non-destructive technique.
Watch the video below to see how conservators use X-radiograpahy.
Read a transcript of this video
Traditionally, the image created during X-raying was captured on photosensitive X-ray film, and developed using the same chemical processing methods as for photographic film. Recently a number of digital processing methods have been developed for X-ray imaging, such as computed radiography (CR). This uses phosphor-coated screens which capture the image until it is scanned by a laser and converted to a digital form.
Here are some more everyday objects that our consevators have X-rayed, revealing a few surprises inside.
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Find out how X-radiography was used to investigate objects and artworks from National Museums Liverpool's collections in the following case studies:
The related technique of computerised tomography (CT) was used to investigate the mummy of Pedeamun.