Facial Reconstruction

Transcription

1 Facial Reconstruction Reconstructing the faces of our ancestors can offer us a fascinating glimpse in to the past. But how is it done, why is it useful in archaeology and how do we know if it is accurate? Facial reconstruction is the process of rebuilding a person s face, usually in clay or plasticine, over their skull. It is often used in archaeology to depict the faces of our ancestors. You may have even seen examples in your local museum or on television. But how do the experts know from someone s bones what they might have looked like? Although you might not think so at first, every skull is just as unique as the face it supports. Some are bigger, some rounder, some longer and some thinner. The size and shape of the skull determines what the face will look like. Experts can read the details of the bones to get clues about the face. For example the shape of the end of the jaw bone can indicate whether you have a dimpled chin or not! The first stage in producing a reconstruction is to make a copy of the skull. This is so that the original isn t damaged in the process. The replica is covered in pegs to represent the thickness of soft tissue at these points. The pegs act as a guide for the amount of clay to be added. Next the muscles of the face are sculpted. Each muscle attaches to the skull at a distinct place, so experts know where and how big to sculpt each muscle by looking at the marks left on the bone. Finally a skin layer is added. Flat sheets of clay are gently placed over the muscle layer and details like the eyes and lips are added. A mould is made of the finished clay head, from which the final reconstruction can be cast in a range of materials from bronze to lifelike wax. Details like skin colour, hair and even eyelashes can then be added. Facial reconstructions are valuable because they tell us lots about the past. Archaeologists can use them to learn about a person s health, dental care, hair styles and even fashion, not to mention what they looked like! Facial reconstructions have also been found to be very successful in engaging A facial reconstruction at the muscle stage The Centre for Forensic Art at the University of Dundee the public with archaeology and getting people interested in their past. But how do we know if facial reconstruction really works? Without a time machine it is impossible to compare the reconstructions with the faces of the people they represent. However, it is possible to produce a reconstruction of someone alive today, by CT scanning their head to get a digital copy of their skull. CT scan (or CAT scan) stands for Computerised (Axial) Tomography scan. It works by taking pictures from all around your The JORVIK Viking Centre in York scanned the skulls of actual Vikings found during the archaeological dig at the site. They then made facial reconstructions of them, so that the Viking people who 'live' in JORVIK are as 'real' as possible. Facial reconstruction can really help to bring the past to life! York Archaeological Trust body, and then a computer is used to put the pictures together to make up a 3D digital copy. A reconstruction can then be produced over this in the normal way and compared with the living person. Results have been very promising and show the reconstructions to be very similar to the target faces. It has also been possible in some archaeological cases to compare the reconstructions with portraits of the individuals they represent. Again, these have usually been very similar to the reconstructed faces, proving that the technique does work! It is said of facial reconstruction that it can never produce an exact portrait of an individual, but it aims to produce a likeness that would be recognized by the individual s friends and family. YAC Attack Facts - Facial Reconstruction! Many famous figures from throughout history have had their faces reconstructed. These include Tutankhamen, King Midas and St Nicholas better known today as Santa Claus! A computerised method of facial reconstruction has now been developed using a technology called Hap-tic feedback. This combines a 3D computer program with a futuristic robotic type arm which gives the user the illusion of actually touching the virtual clay! This is a great new way of making reconstructions without ever getting your hands dirty! It is possible to reconstruct the face of someone who is still alive that s right, you don t even need to be dead! A CT scan can be taken of the head and converted into an accurate model of the person s skull. The reconstruction is then produced just as it would for someone from 500BC. 10

2 This experiment will help you discover the different stages of facial reconstruction. It isn t completely scientifically accurate, but we ve tried to make it as close as possible to how the experts do it! 4 You will need: Plastic skull (from a joke shop!) Matchsticks Ruler (with mm marked) Scissors Before you start, look at the diagrams below. Each number refers to a point on the skull where you will need to attach a peg (matchstick). The points have special names, and each peg is a different length (see below). The peg lengths have been worked out by experts who have studied lots of different skulls and faces. The pegs tell experts how deep the tissue and muscle is at various points on the skull. The measurements we have given are for an adult female; check out the YAC website for peg lengths for other people. We have rounded each measurement to the nearest millimetre (mm) ; peg length 6mm 2. ; peg length 8mm 3. ; peg length 2mm 4. ; peg length 6mm Method: 1. Draw the points from the diagrams onto your skull 2. Make your pegs out of matchsticks. Measure and cut them carefully, using the list above. You will need one of each of the pegs for 2 points 1 5, and two of each of the pegs for points 6 8. You should end up with 11 pegs in total. Reconstruct a face! Blutack Pen/pencil Air-dry clay Cup of water Old rolling pin 5. ; peg length 8mm 6. ; peg length 5mm 7. ; peg length10mm 8. ; peg length 11mm Attach your pegs to the right points on your skull using blutack. Make sure that one end of each peg is touching the skull to ensure that the pegs are the correct depth. 4. Roll out sausages of clay and begin to build up the muscles and fatty deposits on the face, using the pegs as guides. You should still be able to see the tops of the pegs. Also make two eyeballs and put them into the eye sockets. 5. Use a bent matchstick to make a template for the nose. This should start from the bone and end at the bone (see diagram). You will need to decide how big the angle of the nose will be. Noses are one of the most difficult parts of a face to reconstruct accurately. At this stage you also need to build up the tissue around the eye sockets. 6. Roll out a thin piece of clay and place it carefully over your nose template. Smooth in the edges to the cheeks, using a little bit of water to ensure that it sticks. 7. By this stage you should have built up all the muscles and tissue to the level of the pegs, and made your nose and eyes. It is now time to add a layer of skin. Roll out thin sheets of clay (about 3mm thick) and carefully lay them over the muscle layer. Start with pieces going over the top of the skull and then work your way around the rest of the head. 8. Roll out sausages for the lips, and finish shaping the nose. 9. Bonnie s face has been reconstructed! Your next challenge is to add hair, eyelashes and ears. These are all parts of a reconstruction that are more difficult to decide upon scientifically. Good luck, and remember to send in photos of your reconstructed faces! Visit the New York State Museum website for a technical look at facial reconstruction: crsp/arccrsppearlstfacial.html

3 YAC ATTACK Extra information You can use the table for the different facial reconstruction peg depths for different types of people. The peg numbers given along the top of the table refer to the points on the diagram in issue 131 of Young Archaeologist magazine. We have used the average figures for each type of person, and have also rounded the numbers to the nearest millimetre to make it easier for you to measure and cut your matchstick-pegs. Type of Male Female Male Female Male Female Male mm 8mm 2mm 16mm 8mm 5mm 10mm 11mm

4 Type of Female Male 60+ Female 60+ Male Male Male Male Female

5 Type of Female Female Female Female 3 8 Male 3 8 Female 9 13 Male 9 13 Female Male

6 Type of Female 3 8 Male 3 8 Female 9 13 Male 9 13 Female Male Remember that if you want to reconstruct a child s face, you will need a smaller skull to start with. GOOD LUCK!! And remember to send photographs of your finished facial reconstructions to YAC HQ in York at St Mary s House, 66 Bootham, York YO30 7BZ or by to yac@britarch.ac.uk