Toni Owen – BKM TECH https://www.brooklynmuseum.org/community/blogosphere Technology blog of the Brooklyn Museum Fri, 04 Apr 2014 18:19:45 +0000 en-US hourly 1 https://wordpress.org/?v=5.5.3 Many Hours for a Split Second /2011/08/04/many-hours-for-split-second/ /2011/08/04/many-hours-for-split-second/#comments Thu, 04 Aug 2011 17:36:43 +0000 /?p=5008 detail of white impastoDhanashri Ragini showing void.Chandhu La’l With the initiation of the project Split Second, Joan Cummins, Curator of Asian Art selected a very large number (185) of works from the Museum’s Indian Painting collection to post on our website for the Split Second survey. Both Conservator and Curator assessed this checklist to preemptively eliminate any works with condition problems requiring extensive treatment.

Split Second paintings in the Conservation Lab

Works were brought into the Conservation Lab in late April.

Our time frame for conservation of the paintings was relatively short: images of the ~180 works were posted online in February and March. The data was assessed in April and 11 paintings were selected. Thus we had about 8 weeks prior to the exhibition to complete our examination of each painting and undertake any needed treatment and framing. We brought the works to the lab in late April for review.

A very common condition problem with Indian painting is paint instability. There are several reasons for this: these paintings are made from opaque watercolors, applied in many layers between burnishing and often thick dots of paint (impasto) are applied over the surface as decorative elements. These multiple layers and peaks of paint are subject to cracking, lifting and detaching.

Photomicrograph

Photomicrograph showing small previous losses in the pink pigment as well as a lifting flake of white paint at the center.

Seven of the eleven works in Split Second had loose and flaking paint when examined inch by inch under the microscope. In this photomicrograph (left) you can see small previous losses in the pink pigment as well as a lifting flake of white paint at the center. Though it looks obvious at this magnification, paint instability is often only discovered with the aid of a microscope. If not secured, flaking paint can detach completely leaving a void. Usually the paint surrounding a void then becomes loose. Thus consolidation of loose and lifting paint using a variety of adhesives is critical.

Previous losses are usually accepted as part of the age of the painting in Indian miniature paints and the responsibility of Conservation is to prevent additional losses from occurring, rather than to cover up old losses. Sometimes, however, a decision is made by the curator and conservator to fill a previous paint loss; this was true in the case of Dhanashri Ragini (80.277.9).

Lastly housing each of the paintings in archival rag mats to accommodate the paint and support is considered. Note that Chandhu La’l (59.206.2) and the folio from the Qissa-I Amir Hamza (24.46) both have strong undulations in the sheet, (i.e. they do not lie flat as most of the other paintings do.  This is because both are double sided and have multiple layers of paper, fabric etc. which naturally cause distortions).

Decisions can be made within a split second but conservation and preservation take much longer. Enjoy the exhibition.

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The Egyptian Papyrus “Book” /2010/07/15/the-egyptian-papyrus-book/ /2010/07/15/the-egyptian-papyrus-book/#comments Thu, 15 Jul 2010 17:59:56 +0000 /bloggers/2010/07/15/the-egyptian-papyrus-%e2%80%9cbook%e2%80%9d/ Once a papyrus sheet was formed it was joined together with other sheets to form long rolls. The papyrus roll format dates back to ~3,000 BCE and there is little evidence individual sheets were ever used alone. Smaller papyrus documents were either from halved or quartered rolls cut to certain lengths.

To make the roll, individual sheets were overlapped slightly; normally the sheet on the right overlapped the sheet on the left by 1-2 cm. The overlap was pasted, pressed and possibly burnished. Recent analysis has identified starch paste in the joins of several ancient papyri. Twenty sheets was the standard roll.

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The completed roll or book was then rolled with the horizontal fibers on the inside and the vertical ones on the outside. If rolled in the opposite direction (vertical fibers inside) the fibers would have been crushed. The roll format explains why a laminate structure of perpendicular fibers was necessary. The rolls were stored either upright in vertical containers or in chests.

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The height of the rolls varied in different periods. From ~2700-2200 BCE the maximum height was between ~8 and 9 ½”; while in the New Kingdom period ~1500-1100 BCE the average height was ~16″.

All types of recorded information were written on papyrus rolls or sections of a roll including legal, medical, administrative, mathematical and personal documents. In the 18th dynasty (~1400 BCE) funerary texts began being copied onto papyri rolls and placed in wealthy burials; these became known as Books of the Dead.  These books usually read right to left and are unrolled from right to left.

The Book of the Dead of the Goldworker of Amun, Sebekmose a New Kingdom papyrus dating 1430-1400  measures 14″ in height and consists of 18 joined full sheets (each~16″ in width) and one partial sheet. The joins are easily identified in transmitted light as darker vertical lines due to the added opacity caused by the overlap.

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One of the most unusual features of this Book of the Dead is that it is written on both sides of the papyrus. Normally scribes would avoid the vertical fiber side (verso) because it formed the outside of the roll and received the most wear, while the horizontal fiber side (called the recto) was better protected being on the inside.  As expected the spells and chants begin on the recto side. They are written in vertical columns in hieroglyphs and read correctly from right to left. The final spell, on the far left of the roll is completed just past the join of the 18th and 19th sheet (the area represented by the black parallel lines in this image).

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Note the last hieroglyph does not reach the bottom of the last column. The scribe has completed his work and does not need the extra 1 ½ sheets, thus explaining why there are 18 ½, rather than 20, sheets in this roll.

For whatever reason, and we are not sure why, after cutting off the rest of the roll the same scribe then flipped the roll horizontally and began writing on the verso in hieratic, a cursive form of hieroglyphs.

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Note he begin the script just to the left of the last join which appears slightly lighter in color on the verso. The hieratic spells cover approximately 2/3 of the verso of the papyrus.

Treatment and analysis of this rare Book of the Dead is ongoing and as scientists, conservators, curators and modern papyrus makers continue their research the secrets of ancient Egyptian papyrus will also continue to unfold.

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This post is part of a series by Conservators and Curators on papyrus and in particular the Book of the Dead of the Goldworker of Amun, Sebekmose, a 24 foot long papyrus in the Brooklyn Museum’s collection. This unique papyrus currently in 8 large sections has never been exhibited due to condition. Thanks to a generous grant from the Leon Levy Foundation, the entire papyrus is now undergoing conservation treatment. The conservation work is expected to last until fall 2011 when all 8 sections will be exhibited together for the first time in the Mummy Chamber. As each section is conserved, it will join those already on exhibition until eventually the public will see the Book of the Dead in its entirety.

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Papyrus: Secret of the Egyptians /2010/06/23/papyrus-secret-of-the-egyptians/ /2010/06/23/papyrus-secret-of-the-egyptians/#comments Wed, 23 Jun 2010 12:57:51 +0000 /bloggers/2010/06/23/papyrus-secret-of-the-egyptians/ Although the making of papyrus as a writing support is almost 5,000 years old, not a single written description by the Egyptians exist to explain their process.

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Pictorial displays in tomb murals and carvings never reveal the process of sheet formation, though often depict the papyrus plant. Only one document by Pliny the Elder, Natural History, XIII, written in the 1st c. A.D.  attempts to describe the process of papyrus making. Unfortunately, this description is ambiguous and so lacking in details it has led many to believe Pliny never actually saw the process first hand. By the 10th c. AD papyrus making becomes extinct and the secret of its fabrication appeared to be lost.

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Papyrus is made from the sedge plant, Cyperus papyrus which grows in shallow water and was so abundant in ancient Egypt it was the source not only for the manufacture of flexible writing supports but for many everyday items such as shoes, coverings, boats, and food.  Ironically, by the 20th century this plant no longer existed in Egypt though it has since been imported and cultivated. We don’t know whether the ancient Egyptians used wild or cultivated Cyperus papyrus plants of which there are many sub-species. Any one of these sub-species could have affected the quality and finish of a papyrus sheet. Nor do we know the tools and equipment which might have been used by the workshops producing the papyrus sheets. Thanks in large part to scientific analysis, conservation examinations and modern attempts at papyrus making by researchers, curators and conservators we have unlocked some of the basic secrets ancient Egyptian papyrus making.

The Egyptians cut the triangular green stalk close to the waterline and eliminated the flowering head.

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When the outer green rind is removed a soft white triangular pith is exposed (above).  The pith was cut into strips either along the triangular faces of the stalk or straight through the triangle. At times the pith was unwrapped down to its core (below).

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Scanning electron microscopy (extremely high magnification) can distinguish between the strip or peel method and indicates that both were used in antiquity. The strips or peeled papyrus were soaked in water to swell the fibers and cells. While wet the white pith yellows and darkens. Individual strips were laid upon a smooth surface, side by side and slightly overlapping. Then a second set of strips were laid onto the first, perpendicular to it. The two layered sheet is then hammered, rolled or beaten flat and then pressed while still moist. If the pith was peeled, two layers with fibers perpendicular to each other were pressed together.

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The Egyptians always made papyrus sheets with this two layered laminate structure easily identified in transmitted light by a characteristic grid pattern. The criss-cross dark lines are the fiber bundles which run parallel to the stalk and which transported water and nutrients. Because of the perpendicular laminate structure, the fibers run horizontally on one side and vertically on the opposite side. The fibers give the sheet its strength. The lighter material in between the dark lines are the plant (parenchyma) cells also called the ground tissue they fill and give body to the framework.

There is still debate over whether the Egyptians added a glueing agent to adhere the two perpendicular layers of papyrus together. It is possible they did so in certain periods and not in others. Analysis and a variety of modern experiments repeatedly show that papyrus could have been made without any extraneous adhesive. The explanation for adhesion of the two layers to form a sheet is a physical and mechanical one. The parenchyma cells or ground tissue are stacked in a honeycomb like network running the length of the stem. These cells (red arrow) surround large hollow air ducts (green arrow) and look like this at very high magnification.

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When  pressure is applied to overlapping strips of papyrus and to the perpendicular layers (press, rolling, hammering etc) the air ducts collapse causing the plant cells to merge into each other filling the hollow spaces and forming a dove-tail like join. Upon drying the merged cells lock causing complete and long term adherence between the layers and creating a sheet of papyrus.

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This post is part of a series by Conservators and Curators on papyrus and in particular the Book of the Dead of the Goldworker of Amun, Sebekmose, a 24 foot long papyrus in the Brooklyn Museum’s collection. This unique papyrus currently in 8 large sections has never been exhibited due to condition. Thanks to a generous grant from the Leon Levy Foundation, the entire papyrus is now undergoing conservation treatment. The conservation work is expected to last until fall 2011 when all 8 sections will be exhibited together for the first time in the Mummy Chamber. As each section is conserved, it will join those already on exhibition until eventually the public will see the Book of the Dead in its entirety.

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