A mordant dye must have been used to make an antique blue textile: False. The old blue cloth was created of indigo, a natural color collected from the Indigo plant, which is mostly found in India and Southeast Asia (Zady). Because the blue color is generated from plants that are naturally enriched with a strong mordant, it does not require any additional mordant dye to be added to the cloth. The blue color produced by Indigo was exceptionally fast to wash and light, and it remained a popular dying method until the early 1900s. when scientists have discovered synthetically produce indigo by studying chemical structure of the Indigo. Hence the statement is incorrect.
“I cannot assure that an ancient blue textile was indeed blue 3000 years ago”– this statement is correct. The ancient blue was not indeed blue 3000 years ago. The blue was made from naturally occurring indigo extracted from plants, which is not a blue color rather can give a color closer to the blue. The sample blue fabrics discovered recently shows that even the 1500 years’ old fabric contains indigo dyed color, which is closer to the blue hue (Netburn). Experts believe that the fabric has been made with the 6000 years’ old Peruvian technology of Indigo dye, which was mostly known as blue fabric. They further believe that the modern blue color is indebted to the Peruvians for the Indigo colored fabrics.
Kermes can be used as a vat dye. Almost any dye can be used as a vat dye and any type of fibers can be dyed with vat dye except the wool. Cotton are mostly dyed with vat dye. It involves a reduction reaction, which requires extensive use of caustic soda and high pH, which can degrade the quality of wool fabric. Kermes gives a reddish hue, which is mostly extracted from the insects from Kermes vermilion genus ("Dying arts”). Hence the statement is correct.
“Parchment’s chemical makeup is the same as paper”– the parchment paper is made from the running sheet of paper pulp used to make papers. The paper pulp is made to run through the sulfuric acid bath or zinc chloride bath like the construction of tracing paper. The chemical treatment during the production of parchment creates a heat resistant, high sulfur-rich density, stability and low surface energy materials, which finds its wide application in non-sticky and release activities (S. Converse). Obviously, the chemical makeup is quite different from paper but not the tracing paper. So, the statement is not correct.
“Egyptian Blue was used in illuminated manuscripts”- Ultramarine, one of the most expensive ancient pigment was used to write illuminated manuscripts during 14th and 15th centuries (Webexhibits). On the other hand, the first synthetic pigment, Egyptian blue, which is made of calcium copper silicate, has been used for thousand years in Egypt. It finds its modern application in laser technology, security inks, telecommunication and biomedicine because of its unique luminance property (Accorsi, et al.). Hence the statement is not correct.
Answer to Question No. 02
Answer to Question No. 03
Prussian Blue and Iron Gall ink are not similar in terms of their chemical makeup and their preparation. Prussian blue has a chemical formula of Fe7(CN)18, whereas iron gall ink is prepared from the mixture of tannic acid (C76H52O46) solution and iron sulfate (Fe2SO4).
Prussian blue is manufactured from iron blue pigments that are produced in an aqueous solution of iron (II) salts in the precipitation of complex iron (II) cyanides. A white precipitate is generated in the first stage through the chemical reaction between potassium, ammonium or sodium ferrocyanide along with the ferrous sulfate. Oxidation follows the digestion of the product in hot sulfuric acid; the oxidation is performed using sodium bi-chromate or chlorate to transform it into iron blue. The Prussian blue can be extracted from the iron blue through filtration, wash and drying of the iron blue from the oxidation product ("Prussian Blue | C18Fe7N18 - PubChem").
On the other hand, tannin that is mostly extracted from galls is used along with iron sulfate (vitriol), gum and water for Iron gall ink manufacturing process. The production process is easy and inexpensive. The ink was a preferable choice for the artists and painters because it finds its good application in drawing, painting, manuscript and music scores. In a water filled aqueous environment, powdered galls are mixed with gum and vitriol. Filtration is done as per requirement. Sometimes the ingredients are mixed in dry format and stored for use; the user can add water before using the ink and prepare a good workable solution. The dry mix is good for travelers and for preventing the growth of mold. It is also possible to dry a liquid ink for the purpose of traveling or storage and add required amount of water to make the ink back in life. To extract the gallotannic acid or gallic acid from galls, galls are crushed and boiled in water. Sometimes acids like hydrochloric acid or vinegar is added to increase the percentage of the gallic acid. Fermentation is done to create highly pure gallic acid.
From the above discussion, it is evident that the Prussian blue and iron gall ink are distinct from each other in terms of their chemical makeup and preparation method.
Answer to Question No. 04
An ink similar to iron gall ink can be prepared using wood because it contains tannin. Tannic acid is a basic component of the chemical staining of woods like Oak, Mahogany and Walnut. It is not a true acid but polyphenol, an acid like substance, found mostly in woods and plants. Major sources of tannic acid are tea, Oak, coffee, myrobalan and sumac bark (Woodfinishsupply.com). Tannic acid in Oak tree remains in the form of galls, which can take either amorphous or globular or round in shape. The galls contain tannic acid in the form of gallotannic acid, which is processed to yield tannic acid used for the production of iron gall ink. Therefore, it is obvious that the iron gall ink can not only be produced from woods rather wood is the main source of the ingredients of the iron gall ink.
Answer to Question No. 05
Mordants or dye fixatives used in the class varied largely in their chemical composition and overall effect on the color of the dye the used with. Since mordants react with the dyes to create coordination complex that is responsible to fix the tissue or fabric with the dye, they must have effect on the color of the dye. Of several mordants used in the class, tannic acid, various salts from aluminum, iron, potassium and sodium, copper sulfate and chrome are important.
Tannic acid, a polyphenol with weak acidity (pH in the level of 10), is a good mordant used in ink like iron gall ink. Commercially produced tannic acid has a chemical formula of C76H52O46, which is a mixture of polygalloyl glucoses. It is mostly extracted from trees and plants. The use of tannic acid as a mordant ensures high fastening of dye with the fiber like cotton. It increases the glace of the dye color and makes it darker.
The salt of aluminum (aluminum potassium sulfate) is mostly used in textile industry, which has the chemical formula of KAl(SO4)2.12H2O. It is known to have less impact on the color of the dye and keeps the original shade of the dye.
Copper sulfate (CuSO4) is mostly used where it is important take out the green hue of the dye and make the fabric greener.
Chrome has a chemical formula of K2Cr2O7 and is a dichromate of potassium. It can brighten the color of the dye and finds its application in the dyeing of wool. It is toxic and handling of the mordant is highly dangerous.
Answer to Question No. 06
Synthetic fabric cannot be colored by ancient dye but with the modern dyes. Some synthetic fabrics include nylon, polyester, rayon, acetate, latex, orlon, acrylic and so on. There are many reasons for synthetic fabric not going good with ancient natural dyes. First of all, synthetic fabrics are hydrophobic (Elnagar, et al. 1). Most of the natural dyes are applied with the water solution, which cannot be applied to synthetic fabric due to their less affinity to water. Again, high energy is required to bind natural dye with the synthetic fabric, which is not available naturally. However, many modern techniques including surface treatment of synthetic fabric are used to process synthetic fabric to make them able to take natural dye. Apart from that synthetic fabrics are dyed with synthetic dyes in textile industry.
Answer to Question No. 07
In the dying experiment, nylon behaved like two of the ancient fabrics including silk and wool. Like these two ancient fabrics, nylon has the flexible property. All of these fabrics have short length of fiber and high heat sensitivity level. Nylon and silk have very similar structure, which is why they are often known as twin polymers (Lew). On the other hand, various physical properties like flexibilites, heat sensitivites of nylon match with that of wool, which makes them equal in many properties.
Works Cited
Accorsi, Gianluca, et al. "The exceptional near-infrared luminescence properties of cuprorivaite (Egyptian blue)." Chemical Communications, no. 23, 2009, p. 3392.
"Dying arts." Chemistry & Industry, vol. 76, no. 4, 2012, pp. 36-39.
Elnagar, Khaled, et al. "Dyeing of Polyester and Polyamide Synthetic Fabrics with Natural Dyes Using Ecofriendly Technique." Journal of Textiles, vol. 2014, 2014, pp. 1-8.
Lew, Darrin. "Theoretical Comparison Between Nylon and Silk - Global Warming." Best Treatment for Diabetic Nerve Pain - Dr. Darrin Lew, 5 Aug. 2015, www.drdarrinlew.us/global-warming/theoretical-comparison-between-nylon-and-silk.html.
Netburn, Deborah. "Indigo dye: an ancient history." PressReader.com - Connecting People Through News, PressReader, 17 Sept. 2016, www.pressreader.com/usa/los-angeles-times/20160917/281736973918882.
"Prussian Blue | C18Fe7N18 - PubChem." The PubChem Project, 12 July 2016, pubchem.ncbi.nlm.nih.gov/compound/2724251#section=Methods-of-Manufacturing.
S. Converse. American Journal of Science. S. Converse, 1881.
Webexhibits. "Pigments Through the Ages - History - Ultramarine." Webexhibits, www.webexhibits.org/pigments/indiv/history/ultramarine.html.
Woodfinishsupply.com. "Tannic Acid in Wood Finishing." Wood Finish Supply, Furniture Touch-Up, Finishing, & Refinishing, 1 Oct. 2002, www.woodfinishsupply.com/Tannin.html.
Zady. "THE HISTORY OF FABRIC DYE - ETHICALLY FASHIONED .com." Zady, 6 Apr. 2015, zady.com/features/the-history-of-fabric-dye.
