Some more madder business

Both blogs on colouring bone and antler red with madder (part 1 and part 2) had attracted the attention of the Dutch historical bone and antler craftsmen of Bikkel and Been. Monica, one of the members of the company had been working on a replica of the Gloucester medieval backgammon set - the board as well as the game counters, as it was found complete - for the French re-enactment group Aisling 1198 (the same group that received my alquerque game set). The board dates from  the 11th or early 12th century and is made up of 150 bone pieces with carvings in an art style associated with vikings (Borre, Ringerike and Urnes artistic styles). The boardgame was found in a rubbish pit at the site of the Norman castle. There is no evidence to indicate that the board was hinged. Corrosion from iron pins indicates that the bone inlay was fastened to a wooden base, about 600 by 450 mm in size. 

Linedrawing of the Glouchester trictrac board design. Scan from the book  Schach und Trictrac by Antje Kluge-Pinsker.

The points are obelisk shaped. Roman boards had square points, whereas triangular points appeared in the 13th century. The board includes spaces between points, and rectangular plates laid lengthways down the centre of the board. The latter are covered in an interlaced snake design. 

The original Glouchester board. Photo by Celuici - CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=79572888

The board made by Bikkel and Been for Aisling 1198.

The playing pieces - a full set of 30 -  are in the Romanesque style of the Normans. The pieces average 44.5 mm in diameter and are 7.5 mm thick. It is possible that a lathe was used in the manufacture. A central dimple is present on 26 of the 30 pieces.  Fifteen pieces are made from red deer skull bone and the other 15 from red deer antler (but this is not easily distinquisable for a player). There is no evidence that the pieces were stained to create two distinctly coloured sets. There is also no unifying theme in the symbolism, making it difficult to group the  counters into two sets. Different scholars therfore propose differnt groupings. I must confess that I do not know which grouping has been made for the Aisling replica counters.

The 30 original game counters. Compilation of the photos by Celuici - CC BY-SA 3.0.

The game counters were carved in bone as well as antler and contain scenes from Greek mythology as well as other topics. Each game piece has a different design. For ease of playability with the replica counters it was decided that one set had to be coloured red with madder. Medieval trictrac counters coloured with madder are not uncommon, and can be found in many museum collections (for instance in the Museum für angewandte Kunst in Köln, Germany). They asked if I could help with the colouring process.

There were some additional spare counters made, so the total to be coloured was actually 18 pieces.

Some details of the counters.

Colouring of (half of) the Gloucester counters was done last year November at our house with Sylvestre of the Aisling group present (and doing most of the work). The process was the same as done for the alquerque pieces. The weight of the 18 pieces (there were 3 spare ones added to the 15) was around 320 gram. The counters were presoaked in water for one hour.  During that time the madder solution was made with 14 grams of madder extract and 4 grams of sodium in 400 ml water at 60 degrees Celsius, also for one hour.

Soaking the counters in water.

After that the counters were kept for 2 hours at 60 degrees Celsius in the madder solution. We used 2 jars for the counters so they would touch each other as little as possible, thereby avoiding problems with colouring. After the 2 hours, the counters cooled down overnight in the madder solution. The still wet pieces were then taken home, where walnut oil was applied when the pieces were dry. The walnut oil then needed to dry as well for some weeks. 

Dividing the counters over two glass jars, so that the counters did not touch each other .

Dividing the madder solution equally among the jars.

The counters just after they were dropped in the jar with madder.

A few counters directly after the one hour madder bath at 60 degrees. Some parts were still a bit lightly red coloured.

The wet counters after a one night cool down in the madder solution.

The pieces when dried a bit with a kitchen tissue. I also coloured two small dices.

All the 30 counters on the Glouchester board.

The game counters in use on the Aisling 1198 Glouchester tablas board. Here the board is set-up for 'a game of 'Todas Tablas' (for rules, see the Libre de los Juegos created by king Alphonso X the wise in 1283).

Sources:

• Grandet, M. and Goret, J.F., 2012. Echec et TricTrac - fabrication et usages des jeux de tables au moyes âge', Editions Errance, Paris, France. ISBN 978-2-87772-503-3.
• Kluge-Pinsker, A., 1991. Schach und Trictrac. Zeugnisse mittelalterlicher Spielfreude in Salischer Zeit. Jan Thorbecke verlag, Sigmaringen, Germany.  ISBN 3-7995-4138-1
• Wikipedia: The Glouchester tabula set. https://en.wikipedia.org/wiki/Gloucester_tabula_set

Meddling with madder - part 2

 The results of the dilution test after 24 hours in the madder solution.

With the first experiment on colouring antler with madder done, the basic recipe was elucidated. The next step was to determine which strength of solution led to which red colour strength. To do this a set dilutions was made. So, to recapitulate, the basic recipe was:

• Pre-soaking antler for 1 hour in water
  
• Make madder solution with 4 gram sodium in 400 ml water (a 1% solution) + 5% WOF madder extract for 1 hour at 60 degrees Celsius
• Antler for 2 hours in madder solution at 60 degrees Celsius
• Cool down for 24 hours in madder solution
• Rinse with cold water

Dilution test

For the dilution test a set of five different solutions was made. The basic madder solution was diluted with a 60 degrees Celcius 1% sodium solution in 5 different glass jars:

• 100%  = 200 ml basic madder solution
• 50%  = 100 ml basic madder solution + 100 ml sodium solution
  
• 30%  = 60 ml basic madder solution + 140 ml sodium solution
  
• 20%  = 40 ml basic madder solution + 160 ml sodium solution
  
• 10%  = 20 ml basic madder solution + 180 ml sodium solution
  

The results of the dilution test directly after 2 hours at 60 degrees C. The (quarter) antler pieces are at the back, while the elongated bone pieces are at the front.

As I also had some (cow) bone pieces leftover from making soup, these were added as well to the test. The antler and bone responded differently to the dilution test. The bone produced a much lighter shade of red than the antler. This could be due to the fact that the bone was still 'fatty', and thus less able to absorb the madder. Or it might be that (cow) bone is less able to absorb the madder than antler. The 50% solution looked most agreeable to me, having a full red colour and not being too dark red. This solution was chosen for the production of the coloured tablemen.

Finalisation

The results of the actual colouring of the tablemen were not as straightforward as thought. The coloured antler game pieces had different shades of red, giving it a spotted appearance. Also, a wet solution brings out the fibres (just like wood), giving the game piece a slightly rough texture. Especially, the porous inside of the antler produces the most 'rough' texture and needs sanding to make it smooth again. The first game piece was sanded to much, and blank bits appeared. Therefore, I repeated the colouring procedure on the same game pieces in order to darken and recolour the light coloured spots. The result was that the game pieces were now a dark red colour.

 

 When you saw the test pieces in half you can see that the madder colour consists only of a small layer on the bone and antler. only on the porous part it invades further into the tissue.

 

 

The wet tablemen showing a spotty colouring.

When the tablemen were dry, the porous parts were carefully sanded with a 320 grid sanding paper, after which the complete gaming piece was polished with a cotton polishing wheel. Afterwards the piece was oiled with walnut oil, just as it was described in the 12th century treatise by Theophilus. 

 

The 100% and 50% madder solution test pieces with walnut oil.

 

 

Some of the madder coloured and uncoloured antler tablemen after the walnut oil finish.

Meddling with madder - part 1

I have been quite intrigued by the red coloured medieval tablemen that are found in the different museum collections around the world (for instance the Metropolitan Museum of Art, the Victoria and Albert Museum, the Museum für Angewandte Kunst Köln, among others). How were these pieces coloured and is this easy to reproduce? The how was easily answered, as the monk Theophilus provides a recipe in his book 'On divers arts' which was written around 1122 - a similar date as most of the red game pieces, which were manufactured in workshops in Cologne, Germany.

A game piece with Samson slaying the Philistines with the jawbone of an ass. Madder coloured walrus ivory. 6.3 by 1.3 cm. Made in Germany around 1140-1150. Photo Metropolitan Museum of Art, Cloisters, New York, NY, USA.

 

Theophilus writes in Chapter 94 of his book:

'There is also a plant called madder, whose root is long, thin, and reddish. After it is dug up, it is dried in the sun and pounded in a mortar with a ball. Then lye is poured over it and it is cooked in a raw pot. When it has boiled well, if the bone of an elephant or a fish or a stag is put in it, it will become red. from these bones or horns knops can also be made on the lathe for the staves of bishops and smaller knops for various useful objects. When you have turned these with sharp tools, smooth them with shavegrass. Collect the shavings on a linen cloth and, still turning the lathe, rub them vigourously on the knops which will then become completely shining. You can also polish horn-handles, huntsmen's horns, and [horn] windows in lanterns with sifted ashes on a woolen cloth. But do not forget to smear them finally with walnut oil.'

Of course the bone of an elephant is ivory, the bone of a fish relate to normal animal bone, and the bone of a stag is antler. I am unsure if Theophilus also means that (cow, goat) horns can be stained, as these have a quite different structure more similar to nails and hairs. However, wool for medieval clothing is commonly stained with madder. There is evidence that madder was already cultivated for this purpose in the Netherlands in the 12th century; in later centuries the Dutch madder became famous for its quality.

A similar uncoloured game piece with Hercules throwing Diomedes to his man-eating horses. Elephant ivory. Made in Cologne, Germany around 1150. Diameter 7 by 2 cm. Photo Metropolitan Museum of Art, Cloisters, New York, NY, USA.

As I was making a set of alquerque game pieces from antler, I wanted to make one set coloured red. The recipe of Theophilus was not very specific. In fact it looked more like a medieval cooking recipe without amounts. Searching on internet did show many recipes for colouring with madder, but these all concerned wool or cotton, and all are different as regards to amounts of the ingredients. 

 

A mordant - alum - is needed to fix the red colour to wool. The wool is first treated with the mordant, and then to the colouring solution. For cotton and hemp, both non-animal (plant) fabrics, an extra pretreatment is necessary before the alum. On the other hand Theophilus, as well as the early 18th century scientists do not mention alum at all for bone colouring. 

There are also other steps in the colouring process that need to be considered: temperature influences the colour; a temperature above 82 degrees Celcius turns the red colour into brown (for wool). Hard water (basic pH) increases the intensity of the red colour. The time in the colour solution and the strength of the colour solution influence the outcome as well: the longer, the darker, and more pigments in the solution also make the end result a darker red.

So what is the best way to colour antler madder red? I decided to do some tests to find out.

The first test

Madder powder as well as madder extract was bought from paint mill 'De Kat' in the Netherlands. Madder extract has already the red pigments (alizarin and purpurin) from the root extracted, and is sold as a plaque of dried crystals, which needs to be dissolved again. The madder powder is finely ground madder root, from which the madder pigments still need to be extracted before colouring the antler (or wool). I also purchased some alum from 'De Kat'.

As a basis I used 'the Maiwa guide to natural dyes - what they are and how to use them'. This free pdf guide (provided by the Maiwa company which also sells these pigments) provides a very clear description on colouring for each dye and as well as for mordanting. 

 

Left: The two basic madder preparations from powder and extract in the 60 degrees Celcius water bath. Right: the setup in the kitchen with the meat thermometer at 60 degrees.

 

The amount of dyestuff needed is based on a percentage of the weight of fibre (WOF), in my case the weight of the antler pieces. For madder powder this is 35-100% WOF, for madder extract this is 3-8% WOF. The antler pieces should be just fully immersed in the solution. So the actual amount of water does not matter, the amount of pigment that is available to the fibre does. I used 50% WOF for the powder and 4% WOF of extract.

Left: Pretreated antler pieces: with water in the glass, or with alum in the plastic box. Right: Four smaller test pots in the 60 degrees Celcius water bath.

 

Half of the antler test pieces were pretreated with alum, 15% WOF (as for wool). The other half was only immersed in water. During mordanting, the solution with the antler pieces was kept around 60 degrees Celcius for one hour. The pots with the solution were heated au-bain-marie (a waterbath) in a pan on a low flame and the temperature was kept in check using a digital meat-thermometer. If the temperature started to rise, a bit of cold water was added to the pan. After one hour, the pots were left to cool.

I made 400 ml of each madder solution. The pots with the madder solution were placed at 60 degrees Celcius for one hour in the waterbath, as described above. During the hour the colour of the powdered solution darkened, the extract solution was quickly dissolved and had a similar dark red colour.

 

Then the pretreated antler pieces were divided over smaller pots and the colouring solutions added. To the pots with antler pieces without alum an extra 2 gram of household sodium was added to each madder solution. The sodium carbonate was used to raise the pH of the solution to see if this influences the intensity of the colour. The test consisted of five pots:

• Antler mordanted with alum, madder powder solution, with sodium added during cool-down
  
• Antler mordanted with alum, madder powder solution, no sodium
• Antler mordanted with alum, madder extract solution, with sodium
• Antler with water, madder powder solution, no sodium
• Antler with water, madder extract solution, with sodium

The pots were kept around 60 degrees Celcius in a waterbath for 2 hours, after which they were left to cool down for 24 hours. Then the antler pieces were rinsed with cold water and dried.

Colour after 2 h 60 C degrees bath. The darker red coloured pieces on the right are without alum  pretreatment and with sodium.

The colour after 24 h cool down with the same oder of test pieces. The piece on the far left (powder + S + alum) was treated with sodium during the cool-down period and gained in colour strength.

As it turned out, mordanting with alum did have no positive effect on the colouring process for antler. Sodium, on the other hand, did. All antler pieces in a solution containing sodium were dark red, the one with sodium added later medium red, while those without were only lightly red coloured. Both the madder extract and the madder powder did colour equally well. Madder powder is cheaper than madder extract, but madder extract is a clearer solution and does not have the risk of the powder grains to become affixed to the antler. So the extract was used for further experimentation (in the next blogpost).

A side note

 

Science also had an early interest in colouring bones red. The first scientific study on the effects of madder on bones is from the early 18 century by M. Du Hamel du Monceau and published in the Philosophical Transactions of the Royal Society of London. An observation from a surgeon eating a pig with red bones, led to experiments where pure ground madder was (forcibly) fed to chickens, which died after a few days. Indeed, the chicken bones had become all red, but not the feathers.

 

 

Nowadays the synthetic red pigment (alizarin) that is also found in madder is still used to study the growth of bones and their calcium deposits.

Smooth newt (Triturus vulgaris) with bone coloured with alizarin. Bar = 5 mm.

Sources

• G.C.H. Derksen (2001) Red, redder, madder. Analysis and isolation of anthraquinones from madder roots (Rubia tinctorum). PhD thesis, Wageningen University, Wageningen the Netherlands. https://edepot.wur.nl/197629.
• M. Du Hamel du Monceau (1739) Observations and experiments with madder-root, which has the faculty of tinging the bones of living animals of a red colour, by M. Du Hamel du Monceau, F.R.S. & c. Communicated in a letter to Sir Hans Sloane, Bart. Pr. R.S. Translated from the French by T.S. M.D.F.R.S. The Royal Society of London Philosophical Transactions Vol. 41, pp. 390-406. https://www.jstor.org/stable/104301
• Antje Kluge-Pinsker  (1991) Schach und Trictrac. Zeugnisse mittelalterlicher Spielfreunde in salischer Zeit. Jan Thorbecke, Germany.
• Vivian B. Mann (1977) Romanesque ivory tablemen. PhD thesis, New York University, New York, USA.
• Theophilus (1122) On diverse arts. Translated by J.G. Hawthorne and C.S. Smith (1979) Dover Publishing, Garden City, NY, USA.
• The Maiwa guide to natural dyes - what they are and how to use them. https://naturaldyes.ca/instructions 

Medieval chess pieces from antler: individual chess pieces

This post will show the individual chess pieces of the medieval Noyon-like chess pieces made from antler. Some more information on the original pieces and the construction of this set can be found in the previous blogpost.

The pawns

The two surviving pawns from the original Noyon chess set. The number of ribs is different due to the size of the pawn (9 vs 10). Both pawns belong to the same side. They are 30-31 mm high and have a diameter of 16-17 mm. Adjusted scan from the 'Revue archeologique de Picardie'.

Two pawns from each side. Also our (left side) pawns do have different numbers of ribs because of their diameters. The right side had to be newly designed by us and consists of triangles.

The rooks

The two original rooks from the Noyon chess set. Both are from the same side. Height 54/55 mm, width 37/34 mm and depth 20/21 mm, respectively. Adjusted scan from the 'Revue archeologique de Picardie'.

The four sides of a rook from the 'ribbed' side. This one was made from roe antler.

The four sides of a rook from the 'triangular' side. This one was made from deer antler.

All four rooks next to each other.

The knights

The two knights from opposing sides, as can be seen by the different front and backside. They measure 58/57 mm height, 36/30 mm width, and 32/27 mm depth, respectively.  Adjusted scan from the 'Revue archeologique de Picardie'.

All four sides from a knight from the 'ribbed' side. Our knights were adjusted to either the ribbed or triangular pattern, which is slightly dissimilar to the original patterns. The head of the knight has two lines.

All four sides from a knight of the 'triangular' side.

All four knights together. All knights were made from deer antler.

The elephants/bishops

Only one elephant survived from the Noyon chess set. The back looks like the 'ribbed' side. Height 56 mm, width 31 mm and depth 29 mm. Adjusted scan from the 'Revue archeologique de Picardie'.

All four side from an elephant from the 'ribbed' side.

All four sides from an elephant of the 'triangular side'.

All four elephants together. All elephants were made from deer antler.

The queens

Only one queen survived from the Noyon chess set, which has a 'ribbed' backside. Height 57 mm, width 42 mm, depth 34 mm.  Adjusted scan from the 'Revue archeologique de Picardie'.

The four sides of the 'ribbed' queen. Our queens are different from the Noyon one in such that the 'ribbed' variant also has a ribbed front.

The four sides of the 'triangular' queen.

The kings

Both original kings from the Noyon chess set. The differences between the two kings are the wider spacing on the back and the slashes on the triangles of King 2, while King 1 has an extra ring on his crown. Height 78/72 mm, width  46/38 mm and depth 34/37 mm, respectively. Adjusted scans from the 'Revue archeologique de Picardie'.

The four sides of the king from the 'ribbed' side. There is no distinction in crowns of the kings, as I noticed too late the extra ring, when there was not enough space left to add it.

The four sides of the king from the 'triangular' side. 

The kings and queens from the new chess set.

Sources used:

• J-F. Goret, M. Talon and J-H. Ivinec, 2009. Le jeu d'echecs de Noyon dans sons contexte archeologique et historique. Revue Archeologique de Picardie 2009: 79-119.