By Jane Elliott
BBC News health reporter
When we look at somebody for the first time what do we notice?
Making features stand out
Is it the hair, the eyes, the ears or the shape of the face that makes them so identifiable?
If we saw just the skull of our closest relative or friend, who would recognise them?
And how can we begin to imagine what our long lost ancestors looked like from the skulls on exhibition in museums up and down the country?
Police know that if they put a skull on an identity poster they would get little, or no, response to appeals. But add flesh to the bones and you have a real person.
This is where the Dundee forensic art team of Dr Caroline Wilkinson, a facial anthropologist, and artist Caroline Needham come in.
The team works on disciplines such as building facial reconstructions, recreating facial appearances from post-mortem images or illustrations of trauma for use in court cases.
The images are either created in 3D on a computer or else moulded onto the skull, or a model of it.
The recently established department even has one ground-breaking computer facial reconstruction system which enables the user to "feel" the surface of the skull or face on a screen.
The unit, which they say is the first of its type in the UK, will collaborate closely with the arts department, allowing it to create even more realistic images.
Dr Caroline Wilkinson, senior lecturer in forensic anthropology, previously worked in Manchester and on high-profile history programmes such as the BBC's Meet the Ancestors.
She said: "You need artistic skills to produce a lot of the work we do, for instance facial reconstruction requires sculptural skills.
Ears and tips of noses are difficult to visualise
"There is a lot of detailed drawing work involved as well.
"At the same time, you need a sound knowledge of anatomy and forensic anthropology to ensure that the detail is correct.
"It enables us to extract skills from art and forensics and to make the faces more realistic. It gives us an increased level of accuracy and better processes of finishing and texturing."
Having a detailed knowledge of anatomy help the scientists, as knowing the dimensions of the skull can help plot where features such as eyes, ears and nose are placed.
And using knowledge about tissue depth and muscles helps the scientists literally put flesh on the bones.
Forensic artist Caroline Needham said the art collaboration was vital for getting the most realistic finish.
"In the new unit the emphasis is on facial reconstruction and I tend to specialise in facial rendering. Once the head has been cast I paint it up to make it look lifelike.
"Often when we begin we do not have an idea what it is going to look like so we watch it developing as much as any observer.
She said the work was often painstaking, taking weeks or even years to complete if a skull is in fragments.
But a well-preserved skull can sometimes take as little as a week from start to finish.
When the models are completed they can be used to help identify unknown bodies in police cases as well create visual images of our ancestors.
And Dr Wilkinson said the team was always learning from it's experiences. When a person's identity has been confirmed, they compare their model to photographs.
"The results seem to show that we have got a good likeness and that the faces are recognisable.
"But there are still areas that we don't know very much about, like the ears.
"With the shape of the skull you can tell where the ears were and whether they had ear lobes, but not whether their ears stuck out or whether they were very big.
"Other areas, such as the tip of the nose and the exact line of the upper lip, are difficult too."
But she said they had some remarkable results.
When she was based in Manchester she and her team managed to help identify the body of a five-year-old girl, found dismembered in the Netherlands, which led to her mother and partner being convicted for murder.