Re-materializing Seti I

2017

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A combination of CNC milling and Océ 3D printing has been used to produce the facsimile the tomb of Seti I.

Routed information and a positive obtained from a silicone mould

The video below summarizes the processes used to re-materialize the data.

ROUTING Most of the tomb has been carved into boards of polyurethane using CNC routing machines. The walls were routed into panels of approximately 1 x 2 m that were then joined together. Once complete, these panels were assembled to form complete rooms. These are then cut into irregularly shaped sections that could be transported and bolted together with invisible joints.

Most of the tomb has been carved into boards of polyurethane using CNC routing machines

Most of the tomb has been carved into boards of polyurethane using CNC routing machines

The individual panels were assembled to make the walls

ELEVATED PRINTING The elevated printing technology of Océ - A Canon Company, is a form of additive 3D printing. It can create full-colour, textured prints with a maximum size of 2.44 x 1.19 m and a height up to 5 mm. As the walls in the tomb of Seti I exceed the 5 mm, the research and development department of Océ-Technologies created an experimental slicing algorithm and modified the print processes to create monochrome prints with the required relief while maintaining the accuracy. The technology makes use of a UV curable ink. Multiple layers of ink are stacked on top of each other. After printing a layer, the ink is cured before the next layer is applied. The thickness of each layer varies between 2 and 40 microns. The Océ prints were created as negative moulds of the walls of the tomb from which casts were taken. Had Belzoni had access to this non-contact technology, the walls of the tomb might retain their original colour today.

Moulds were made from Océ elevated printed reliefs

Creating moulds from Océ printed reliefs

Detail of mould with the relief information

A positve and negative of a relief panel was obtained from the Océ printed sheets

ELASTIC PRINTING SUPPORT This is done using slightly elastic ‘skins’. The preparation of an elastic printing media was a direct response to practical need. Factum Arte’s flatbed digital printer can overprint in perfect register but it cannot print a detailed and focused image onto an undulating surface. A mixture of three different materials has been developed and is made as required and applied in layers. It is an ultrathin, flexible, slightly elastic material suitable for inkjet printing with pigmented ink.

It is made of two thin layers of ink-jet ground backed with an acrylic gesso and then an elastic, acrylic support. It is built in seven layers rolled onto a slightly textured silicon mould. The skins have a short working life and need to be made freshly to ensure that they stretch and fit the surface in the correct way. The skins can be printed in sheets that are one and a half metres wide and up to three meters long, minimizing the number of joints in the final facsimile.

COLOR ADJUSTMENT With this printer the image can be built up of layers of colour printed in perfect registration. This approach means that both the colour and the tone can be controlled and locally altered to ensure a perfect match. The colour is corrected both digitally using image processing software and in the printing process. This can seem counter-intuitive to many people experienced in reprographic printing techniques. Most commercially available colour 28 management and profiling systems are designed to ensure standardisation with specific printing systems, inks and material coatings. With Factum’s approach, the adjustments made to the colour in the virtual space of the image management software can also be made in the physical space of the printed image. This multi-layered approach changes the way the files are managed. It is dependent on shared experience and constant comparison with the physical colour notes made in the tomb.

POSITIONING THE SKINS Working with a raking light, the skin is positioned and re-positioned until all details in the print correspond to the underlying surface. The fit between the paint and the relief surface is seldom obvious and therefore clearly defined registration points need to be identified. A sharp angle of flaking paint, a defined crack, the edge of a damaged area provide clear registration points. In the case of the tomb of Tutankhamun, the slight relief and clearly defined edges of the micro-bacteria were the dominant positional guides. The Tomb of Seti I is more complicated. The elastic nature of the support means the colour data can be stretched or compressed to ensure a perfect fit.

When the flexible skins are in the correct position they are pinned in place and locally folded back. A contact adhesive is applied to both sides. A slow-cure contact adhesive ensures that the skins do not move but the bond is not strong so they can be repositioned as required. Sight and touch are essential to ensure the exact relationship between the surface and the colour.

VACUUMING THE SKINS Once the skins have been positioned, pressed down in place and held by contact adhesive they are put into a vacuum bag with a polyester blanket. A uniform pressure is applied using a vacuum pump ensuring full contact and adhesion between the skin and the support. Due to the gossamer-like, elastic nature of skin, it takes on the character of the underlying relief resulting in a surface where the colour and texture are fused together.

Colour and relief information were vacuum sealed

Vacuum sealing the panels

Securing colour and relief

THE SARCOPHAGUS The physical recreation of the Sarcophagus presented a series of challenges due to its size, the complexity of the form, the translucent nature of the material, its complex featuring and the very subtle carving on the surface of the entire interior and exterior faces of the sarcophagus. The final solution that was adopted is the result of some remarkable advances in 3D printing technology being developed by Océ, part of the Canon group of companies.

Océ elevated printing was used to print the colour infromation of the sarcophagous

Printing layers of colour and relief progressively

Printing layers of colour and relief progressively

Printing layers of colour and relief progressively

Their elevated printing system can build up a surface in full colour in 5 micron layers. However, the challenge of digitally separating a very thin skin from the surface, flattening it onto a flat plane but keeping the surface relief, and then fixing it back onto a CNC milled rendition of the Sarcophagus without its surface was both conceptually, intellectually and technologically challenging. This work was carried out in Factum Arte by a team led by Enrique Esteban using Global Mapper software.

The shape of the sarcophagous was 3D printed

The sarcophagus was 3D printed and the colour and relief information printed by Océ

The colour and relief information of the sarcophagus was printed in panels

The fragments of the lid of the sarcophagus were 3D printed and hand painted. They are presented in the same cases as they are conserved in the Sir John Soane Museum.

The fragments of the lid of the sarcophagus were 3D printed.

Each fragment was hand painted

The fragments were assembled to reconstruct the lid

Some of the fragments of the lid.

RETOUCHING THE FINAL FACSIMILE Once the skins are fixed to the surface, there is some retouching required to ensure perfect contact and no visible artefacts. This work is done by a team working under Factum’s restoration specialist.

Adding the final touches to the panels.

Finally, the panels were mounted and assembled for display in the exhibition ¨Scanning Seti. The Regeneration of a Pharaonic Tomb¨

Assembling the panels of the Hall of Beauties

Assembling columns

Detail of the colour and relief of a panel

Facsimile of the lid of the sarcophagus

TO LEARN MORE
Visit the exhibition Scanning Seti: The Regeneration of a Pharaonic Tomb.

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