Charcoal

Charcoal can be made with a variety of carbon sources.  I will address bone black separately from charcoal made from plant sources.  Mentions of multiple sources of charcoal are listed in period sources made from things such as leather, hay, wood (except oak)[1], and elm bark[2].  Most prized was that of grape vines.  This black was referred to as tryginon by Pliny, and was also listed as atramentum[3] and niger by other sources.[4]  De Arte Illuminandi describes the process as this:

First, and most generally, it is made very satisfactorily out of vine-twig charcoal, that is, by burning twigs of the vine from which wine comes; and before they turn to ashes, water is thrown on them, a little at a time, and they are allowed to go out, and the clean coals are separated from the ashes.[5]

Cennini’s instructions are very similar:

These [vine] twigs are to be burned; and when they are burnt, throw water on them, and quench them; and then work them up like the other black.  And this is a color both black and lean; and it is one of the perfect colors which we employ.[6]

Other sources of plant material include peach pits and almond shells.  The Marciana Manuscript mentions that charred peach stones make a “perfect black.”[7] Cennini refers to both burnt almond shells and peach stones as a “perfect black, and fine.”[8] The Paduan Manuscript says that burnt almond shells can make a black pigment.[9]  The Brussels Manuscript mentions not only peach stones, but also plum stones, and mentions that the fruit stones should be extinguished with vinegar to make a “most excellent black.”[10]

 

Figure 1 "Crucible": a 1 1/4" pipe fitting with two end caps.

I sought to create as many kinds of charcoal black pigments as I could.  Since I was lacking grape vine twigs, I first took charcoal from burned maple and ground it.  This was easy, quick, and cheap and produced a deep, opaque black when combined with gum arabic to create a paint. 

 

I then saved and cleaned peach pits and almond shells to char them.  So that the small peach pits and pieces of almond shells would not be lost in the fire and would not burn too quickly and turn white, I put the materials in a “crucible”.  Since the literature gives few hints as to how this black is made other than the source material, I searched online and found a mention of using a crucible covered in coals to char the material in the absence of air.[11]  Cennini also mentions using a “casserole” to create a low oxygen environment to make charcoal sticks for writing[12].  I looked into obtaining a period appropriate casserole to use to make my pigments.   I learned that in order to put a clay vessel directly into a fire, the clay used would have to be a special flameware clay to prevent shattering in the fire.  I was unwilling to spend the $60-$200 for a flameware casserole to make pigments.

 For my crucible I used a black pipe fitting with a cap on each end and loaded my material into this container. I then put the container into the fire for about an hour.  I removed the pipe from the fire and allowed it to cool before emptying the contents.  The peach pits and almond shells retained their original shape and texture, but decreased in size after charring.

The almond shell ground differently that the charcoal.  The feel of grinding the charcoal was slightly spongy, while the almond shells felt harder and wanted to shoot small pieces out of the mortar.  The almond shell seemed to resist a fine grind and took more effort.  When made into paint, the almond shell made a blue black that quickly shades to a pleasant grey. 

Charred peach pits ground more easily than the almond shells.  The resulting paint is a deep, rich black.  I would agree with Cennini that is a most perfect black.

 

Bone Black

 

Figure 5 Charred ivory scraps

Figure 4 The crucible is placed into a hot fire

Figure 3 Ivory scraps in the crucible

Figure 2 Mammoth ivory scraps

Bone black and ivory black are often combined in literature, ivory black being included in the name “bone black”.  The Marciana Manuscript mentions ivory black specifically along with peach stones as substances that can be charred to make a “perfect black”.[13]

 

 

I used the same crucible and method as I did with the peach pits and almond shells to char a variety of bones. I found that it is best to clean the bones as much as possible, boiling the fat and meat off if possible, but at least to dry them completely or mold will grow on the bones.  The mold does not seem to affect the pigment.  I started with chicken bones, then tried pork rib bones, and then turkey bones.  I was gifted some mammoth ivory pieces and charred that using the same process.[14]

 

Figure 2 Charred chicken bones

The bones produced a wide variety of black pigments.  Chicken and turkey bones produced a beautiful blue black, perhaps since the bones are thinner and were able to carbonize more completely.  Pork ribs produced a brown black.  Black pigment made from mammoth ivory made a brown black similar to that made from the pork rib.  According to Pigments Through the Ages, ivory black pigment is high in calcium phosphate, making it the least pure form of carbon black.[15]  The high percentage of calcium phosphate must account for the brown color.

 

 

Lamp Black

Lamp black is the soot primarily from a lamp or candle, but also chimney soot.[16]  The Paduan Manuscript mentions using both the smoke of nut oil and of burnt rosin.[17] In different sources, lamp black is listed as atramentum, fuligo, fumus, fuscus, niger, sanctonicus, and sable.[18]  The process is essentially collecting the soot of a lamp or candle with a bowl or such held over a flame and then scraping the collected soot.  De Arte Illuminandi describes the process like this:

Get a clean basin of brass or glazed earthenware, and put under it a lighted candle of clean wax, and have the flame almost reach the hollow of the basin; and carefully collect that black which is produced by the smoke.  And put <the candle back again> and make as much of it as you want.[19] 

 

Cennini describes a very similar process:

Take a lamp full of linseed oil, and fill the lamp with this oil, and light the lamp.  Then put it, so lighted, underneath a good clean baking dish, and have the little flame of the lamp come about to the bottom of the dish, two or three fingers away, and the smoke which comes out of the flame will strike on the bottom of the dish, and condense in a mass. Wait a while; take the baking dish, and with some implement sweep this color, that is, this soot, off on to a paper, or into some dish; and it does not have to be worked up or ground, for it is a very fine color.  Refill the lamp with the oil in this way several times, and put it back under the dish; and make as much of it in this way as you need.[20]

The Strasbourg Manuscript advises purifying the soot before using by putting lumps of brown soot into lye and boiling it to reduce it to a third.  The liquid was then allowed to settle to allow impurities to settle to the bottom and the liquid above to be poured off, combined with gum arabic, and then used to shade paintings.[21]

Lamp black was the most challenging of the black pigments for me to create.  I set a heat resistant glass dish over an oil lamp filled with linseed oil.  I ensured that the top of the flame licked the glass dish and smoked sufficiently.  The process of making lamp black pigment should be done in a place with little breeze, but with sufficient ventilation to allow the fumes to dissipate.  The odor of burning linseed oil can be quite strong.  Making lamp black pigment will undoubtedly leave small pieces of soot which are not easily cleaned up so the process should be conducted in a place that can get dirty.

 

Figure 3 A heat resistant glass dish over a linseed oil lamp for making lamp black pigment.

At first I tried to use boiled linseed oil from a hardware store, but the amount of soot collected was frustratingly low.  I then used linseed oil obtained from an art store which produced much more soot.  I also tried to create soot from a beeswax candle and a beef tallow candle as mentioned in De Arte Illuminandi,[22] but the candles did not produce any smoke or soot.

 

The process is more intensive than other black pigments.  I had to keep an eye on the length of the wick and the position of the flame near the bottom of the dish.  The wick kept burning down and I would have to adjust the wick to keep the flame at the right height.  The amount of pigment that I collected seemed to be low for the amount of time and effort needed to make the pigment.  When making paint with the lamp black pigment, I added a couple drops of ox gall in order to break the surface tension and allow the oily pigment to combine with water and gum arabic.  My lamp black produced a more brown black than the commercial lamp black, probably due to the impurities found in the linseed oil.  My pigment was still a lovely dark black.  I did not purify my pigment using lye as described in the Strasbourg Manuscript because it sounds like the “lumps of brown soot” described are more like that deposited in a chimney and possibly with more impurities that linseed oil.

 

 

Next Steps

I have used the peach pit black pigment in my other Kingdom Arts and Sciences entry, but look forward to using the pigments in more illuminations.  I have also found a couple of black pigment recipes that call for iron forge scale.  A friend has gifted me some scale from her forge and I look forward to trying these recipes.

Conclusion

Overall, I was surprised by the variety of shades of black that I could create using period materials.  I am impressed by the ingenuity of medieval scribes in turning waste materials into deep, rich pigments.

 

[1] Manuscripts of Jehan Le Begue, Pg 138.

[2] De Arte Illuminandi, Pg 32, Note 37.

[3] Manuscripts of Jehan Le Begue, Pg. 138.

[4] De Arte Illuminandi, Pg. 32, Note 37.

[5] De Arte Illuminandi, Pg. 2.

[6] Cennini, Pg 22.

[7] Marciana Manuscript, Pg. 610.

[8] Cennini, Pg. 22.

[9] Paduan Manuscript, Pg. 650.

[10] Brussels Manuscript, Pg. 820.

[11] Pigments Through the Ages, Bone Black, Making the Pigment.

[12] Cennini Pg. 19.

[13] Maricana Manuscript, Pg. 610.

[14] A note on mammoth ivory:

I used mammoth ivory due to many other ivories being rightly protected by CITES (Convention on International Trade in Endangered Species).  Mammoth ivory is legal since the trade does not decrease the population of a species since mammoths are extinct.  Some estimate that more than 10 million mammoths lie frozen in Siberia.  These ivory tusks have begun to mineralize but are not fully fossilized.

[15] Pigments Through the Ages, Bone Black, Overview.

[16] De Arte Illuminandi, Pg. 33, Note 37.

[17] Paduan Manuscript, Pg. 650.

[18] De Arte Illuminandi, Pg. 33, Note 37.

[19] De Arte Illuminandi, Pg. 2.

[20] Cennini, Pg. 22-23.

[21] Strasbourg Manuscript, Pg. 115.

[22] De Arte Illuminandi, Pg. 1-2.