Islam House

Wednesday, October 6, 2010

Dyeing Processes in Leyden and Stockholm Papyri

The processes of dyeing are treated much more fully in the Swedish papyrus than in the Leyden one, and can better be discussed in connection with that work. Here you will find a comparison of dyeing processes in both papyri***:

Leyden papyrus
Preparation of purple: Break in small pieces Phrygian Stone; bring to a boil and having immersed the wool, leave it till becomes cool, then throwing into the vessel one mina of algae, boil and throw in the wool and letting cool, wash it in sea-water to purple coloration. The Phyrygian stone is roasted before breaking.
Stockholm papyrus
Purple - Roast and boil Phrygian stone. Let the wool stay in till cold. Then take it out; put into another vessel orseille (sea-wood or algae) and amranth, one mina of each, boil and let the wool cool in it.

***It is a pretty evidence (as Berthelot said) that the two recipes are practically the same, the one helps us to understand the other.

Phrygian Stone
-It is considered by Berthelot probably to have been an alunite, or basic sulphate of aluminium and potassium.
-While Pliny describes it as a porous stone resembling pumice which is saturated with wine and then calcined at red heat and quenched in sweet wine-the operation is three times repeated.
-Its only use is in dyeing cloths.
-The algae used are manifestly the source of the dyestuff were probably lichens such as were formerly much used and which yield the dyestuff called archil or orseille.

The notes on dyeing form an important part of the Stockholm papyrus, and furnish more specific information as to methods and materials employed than any other source of information as to the dyeing processes in use in Egypt in ancient times.
The recipes are almost exclusively devoted to the dyeing of wool. The colours range from purple and reds to rose, yellow, green and blue, though the greater number of recipes have to do with purple. That term with the ancients, included deep red and even red brown as well as purples proper.

Hints for testing the quality of dyestuffs
-Woad should be heavy and dark blue if good, if light and whitish, it is not good.
-Syrian Kermes�crush those which are best colored and lightest, those which are black or spotted with white are bad. Rub up with soda and dissolve the fine colored.
-Rub up the best colored madder and so make the test.Purple colored and fast orseille is purple snail-colored, but the white spotted and the black is not good.
-When you rub up very fine colored orseille, take and hold it in your hand. (A rough color test on the palm of the hand?)
-Alum must be moist and very white, but that which contains saltness is not fit.
-Of "flowers of copper" that fit for use should be either dark blue, a very green leek-color or in general possess a very fine color (Flowers of copper, the flos aeris of Pliny, seems generally to be used for the copper oxide)

Methods For Whitening Pearls

Method 1:
If the pearls have a brownish tint as if smoked, it is directed to make a solution of honey in water, to add fig roots pounded fine, and to boil down the mixture. Spread it on the pearls as and let it harden, then remove it and wipe off with a linen cloth. If the pearls are not yet white, repeat the process.

Method 2:
Mordant or roughen the pearls by letting them stand in the "urine of a young boy" then covering them with "alum" and let what remains of the mordant dry. They are then put into an earthen vessel with "quicksilver" and "fresh bitch's milk". Everything was then heated together, the process being regulated. It was cautioned to apply the fuel externally and to maintain a gentle fire.
Notice: Lippmann suggested that "quicksilver" above mentioned cannot be mercury, but was probably some finely divided substance of pearly or silvery character, calculated to give the pearly luster.
** A curious method given for whitening a pearl is that of causing it to be swallowed by a cock, afterwards killing the cock and recovering the pearl, "when it will be found to be white."

Method of making Artificial Pearls:
One recipe of the Swedish papyrus that gives us the earliest account of methods of making artificial pearls is as follows: Mordant or roughen crystal in the urine of a young boy and powdered alum, then dip it in "quicksilver" and woman's milk.
The word "crystal" often meant with the ancients quartz crystal, but it is very evident that with the authors of these notes the term was used in a more comprehensive sense to include other transparent or translucent stones. This use is very evident in the many recipes for imitation of precious stones, where the processes involve a degree of porosity or absorbent power towards colored solutions not possessed either by quartz crystal or by glass, while certain agates, micas, alabasters or other stones possess this property. In case of the above recipe, it is doubtful whether any such mordanting would in a reasonable time roughen the surface of real quartz crystal adequately. The "quicksilver" here mentioned is evidently the same substance of pearly luster previously referred to.
A more elaborate process for making artificial pearls is the following, suggesting the modern "Roman pearls.": "Take a stone easily pulverized, as glimmer, and pulverize it. Take gum tragacanth and soften it for ten days in cow's milk. When it is softened, dissolve it till it becomes thick like glue. Melt Tyrrhenian wax. Take also the white of an egg and "quicksilver."
There must be two parts of "quicksilver" and three parts of stone, but of all other materials one part each. Mix (the stone and wax), and knead the mixture with the "quicksilver. " Soften the paste in the solution of gum and the contents of the egg.
Mix in this way the whole liquid with the paste. Then make the pearls which you wish according to pattern. The paste will soon be like stone. Make deep round impressions and bore them while moist. Let the pearls solidify and polish them well. Treated as they should be, they will excel the natural. "

Trade Names of Materials used in the Recipes
The use of the trade names for the purpose of concealing the character of the substance used where secrecy seemed desirable was not unknown at that period.
There is a passage in Leyden papyrus concerning this and says that: "Interpretation drawn from the sacred names, which the sacred writers employ for the purpose of putting at fault the curiosity of the vulgar. The plants and other things which they make use of for the images of the gods have been designated by them in such a way that for lack of understanding they perform a vain labor in following a false path. But we have drawn the interpretation of much of the description and hidden meanings."
The secret names in this manuscript which are placed with the real names are thirty-seven in number. They are such names as the later alchemists used extensively: "blood of the serpent," "blood of Hephaistos," "blood of Vesta,""seed of the lion," "seed of Hercules," "bone of the phyasimian," etc.
It is very probable that the term "quicksilver" in the preceding recipe takes its name from a similarity in appearance rather than from the deliberate attempt to mystify, for these recipes are for the artisan himself, not for the public, but it is also possible that some special constituents of these recipes were intentionally so named as to avoid advertising unnecessarily the more valuable secrets of their business.
The "blood of the dragon" for the red resin of the pterocarpusdraco is doubtless a surviving remnant of the fanciful names used for mystification. The Swedish papyrus has a few other names of the same character, though in general its vocabulary is plain and direct. Thus the Greek word for garlic is used to designate human feces, sometimes used in mordanting wool. The manuscript itself gives this translation.
The term "blood of the dove" used in the papyrus, Von Lippmann has identified from other sources as meaning red lead or sometimes cinnabar.


No comments: