Handmade carpet dyes: a colorful world
The color of dyeing carpets can certainly be presented as one of the most important options that can double the beauty and effect of hand-woven carpets. The originality of dyes was not only a concern for carpet lovers or makers, but also for states and governments. At the end of the Qajar dynasty that ruled Persia between (1779-1925), when artificial colors were introduced for the first time in hand-woven carpets, the government banned it in 1877 to preserve the authenticity of hand-woven carpets. Dyeing has been a precious, sophisticated and highly valued art in the geographical regions that were famous for the carpet industry, since the beginning of the history of this industry like no other.
Carpets are produced in a wide range of attractive colors, and in this context, specialists in the world of decoration and carpets recommend paying attention to the mood that you want your room to enjoy when buying carpets, as each color of the carpet leaves a different impression in the decor, and dye makers and weavers are well aware of this. Therefore, the mixture of dyes in handwoven rugs has been considered one of the criteria that determine the value of a rug throughout the ages because the most attractive aspect of a rug is the feelings of warmth and passion that the colors leave in any space.
Have you ever thought about where the colors of the carpets that furnish every space in your home come from? In this article, we will provide a very detailed guide on the dyeing used in carpet making.
What is the art of dyeing?
In the distant past, there were two main materials used to produce high quality carpets; Firstly, a high quality, translucent long-fiber wool, and secondly, a rich, natural color obtained from a wide variety of plants, minerals and insects, the latter being what we call 'the art of dyeing'.
A dye is a substance that reflects color by absorbing certain wavelengths of visible light. As for carpet dyeing, it is an art through which the color material is determined in special conditions, whether in terms of temperature or in terms of the structure of the carpet fibers. It is used in dyeing the fibers and affects the color of the carpet. The carpet, more precisely, it can be said that the art of dyeing the carpet means repainting the carpet and fixing its colors with the help of synthetic or natural dyes that will take on the color of the carpet with relative durability.
This industry refers to a process in which fibers and yarns of wool or synthetic fibers are dyed by means of various materials and dyes. Dyeing helps to display the products of the textile industry in different designs and colors. As a result, these products are sold to satisfy the tastes of different customers. Organic dyes are mainly found in animals and plants while inorganic pigments are found in minerals.
In another, more precise definition of the art of dyeing:
It is a process during which a textile product, such as fiber, yarn, fabric, or clothing, is placed in a solution containing dyes and chemicals, to be dyed, and the dye molecules establish a strong bond with the molecules of the textile product with relative durability. In other words, dyeing is a skill in which Dye substance to a certain temperature and time, penetrating into fibers or textile (woven) goods and dyeing them, in dyeing, dye generally refers to all natural or chemical substances that have the ability to dye fibers or textiles, the color of dyed product should not be easily washed off or exposed to light .
Throughout history the main source of dye has been nature, with humans extracting plant and animal sources to obtain dyes but, since the mid-nineteenth century, humans have produced synthetic dyes to achieve a wider range of colors and to make the dyes more stable for wash and general use. 1
(You can read more about the psychology of carpet colors in this article: The Amazing History of Carpet Colors (A Detailed Guide)
History of dyeing in the world
The art of dyeing has a history as ancient as humans on this earth, and humans have always used different materials to paint their homes and even their bodies. And colored liquids, and the observation and discovery of these plants was the first stage for mankind to benefit from the elements of nature, and these dyes were not only for dyeing carpets, but for his clothes and everything he made with his hands. In the beginning, man used these dyes for self-adornment, and these were usually reserved for men only!
In the past, the purpose of this work was to attract the attention of women and keep enemies away, usually this method was the self-grooming of men and this method was popular among Africans, Australians and Aboriginal people, then gradually, as the years went by and with more detailed and better understanding of these dyes, thereafter Finding ways to prepare fibers, these dyes were used to dye fibers and clothes, and in a book attributed to the eighteenth century, it was mentioned that in the centuries before the birth of Christ, dyeing was done by women at home only for their own and family needs!
The art of dyeing in China
The peoples of Asia excel in the art of dyeing, and they are real masters in this art, especially by mixing colors and obtaining luminous, warm and sober tones, so they use natural dyes in great esteem, and it is believed that the first to use dyes were the Chinese (some unreliable sources say that they were the Japanese !)), and the Chinese invented this industry since 3000 BC, and it is also said that the Chinese, even from 2000 BC, were familiar with the red color from the red-seeded insect, and the blue color obtained from the indigo plant.
It should be noted that the reason for the use of dyeing in China is not clear now, after China, and according to historians, tribes belonging to the Hindu religion benefited from this industry, and the history of dyeing in this religion dates back to 2500 BC, and ancient evidence and documents of the Hindu religion show that people At that time they used dyeing, to dye all kinds of silk fabrics, and in this way dyers used this industry to get all kinds of fabrics and fibers in different colors, and based on these works and documents, we can conclude that dyeing fabrics and fibers was very popular among the people at that time.
Also, based on what the ancient documents mentioned about the history of dyeing, it is possible that the dyeing industry was transferred from Iran to Egypt, and the rest of the world, and based on the paintings on the walls of the Pharaonic tombs, it can be noted that the Egyptians also used dyeing and used this method to dye their mats and produce The colored mats that they hung on their walls, by extracting colors from the dye plant that is known today as safflower, and it was used in that period to extract red and yellow colors for dyeing textiles, and around 1450 BC, the Egyptians were surprisingly making textile products with a fine structure and were able to Dye it in different colours.
The art of dyeing in Europe
It suffices from the history of dyeing in Europe, that the dyeing factory on the island of Crete, which is known today as saffron, was used in this period to produce yellow and red colors and for use in all kinds of textiles, and in fact, around 1450 BC, the Egyptians were ready to produce all kinds of textiles very elegantly , and dyed them in different colors using different dyeing methods.
As for the rest of Europe, the history of dyeing in Italy dates back to the time of the Caesars, when they used natural dyes such as the official purple color and dyed the robes of the Caesars with it, and this natural dye was very rare and was obtained from a type of sea snail, while in the countries of England, France and Germany it dates back The dyeing is attributed to a plant called "wasma" (Isatis), which was cultivated in these countries, and this plant contains dyes that were used to obtain the blue color, and little by little, with the passage of time, new dyes were discovered.
The art of dyeing in Persia and Egypt
In Iran, the art of dyeing and dyeing carpets dates back to the Sasanian era and before Islam, because the tradition of carpet weaving and rug weaving has flourished in Iran since ancient times, and many colorful decorations can be seen in the oldest carpets in the world, and there is another reason that proves the existence of this advanced tradition For dyeing in the Sasanian era and even earlier, is the prosperity and development of textiles in this period, because dyeing is one of the industries closely related to weaving, and the Greek historian Xenophon referred to the carpet weaving workshop of the Achaemenid kings in the city of Sard, which dates back to 400 BC.
During the Sasanian period, carpet makers reached a level of skill in textiles, especially silk textiles, that they took over the silk trade between China and the West, and made silk-knitting machines, which soon became famous throughout the Middle East, and many of these fabrics still exist. Existing in European churches, and at the same time it was sent to Byzantium and Rome, and the Sasanian method of using colors differs from the Byzantine method, although the colors used are the same, but the Sasanian colors have less luster and are more moderate and are artistically divided and chosen, and the dyers were revered and respected During the Sassanid era, like carpet weavers.
Among the other effects that show the ancient history of dyeing in Persia are the writings found in the purple carpet carved on the tomb of Cyrus the Great, the first king of Persia. In fact, this carpet is considered one of the first models of Persian carpets, and it can be said that the history of dyeing in Iran It coincides with the emergence of the art of carpet weaving.
According to historians, the exact date of dyeing is not known in which year it dates back, but historians and scholars believe that the history of dyeing and human knowledge of color dates back to three to four thousand years BC, and in fact, the history of dyeing is the same as the history of making fibers and clothing. , People used dyes found in plants and fruits, as well as used colored soil, and produced colorful and distinctive clothes for the rulers of their time, and in this way the art of dyeing became available to the people of later periods.
It can be said that countries such as Iran, Egypt and China were the pioneers of their era in this art..and that the climax of the history of dyeing dates back to the Middle Ages, during this period the production of dyes for dyeing witnessed great progress and expansion, which caused many factories around the world to produce dyes, and launch The art of dyeing.
Everything you need to know about carpet fibers
The first important point in dyeing carpets is the type and texture of the fibers used in the carpets, because the type of carpet fibers is actually what tells us about the type of color and technique that should be used in dyeing carpets. Animal (natural) fibers that are obtained from animals have a protein structure and are divided into Two groups, alkaline and acid, and the carpet dyeing time depends on whether the fibers are natural or synthetic, and the dyeing method also changes, because it is necessary to use a color that is absorbed by the related fibers and can be fixed, for example, natural colors cannot be used for synthetic fibers because they are not absorbed Fine carpet fibers.
Carpet dyeing techniques
The dyeing technique differs from different fibers, but there are always basic steps involved in most dyeing workshops. The following are the most important techniques for dyeing carpets with natural fibers:
- The process begins with degreasing the threads in hot water for about half an hour, adding 3% sodium carbonate with a little soap added in case the fibers are too greasy, after that, the threads are soaked for 12 hours and cooked for an hour in an alum bath (instead of dichromate in Europe).
- The dye is diluted in a tank filled with water, the amount depends on the appropriate dye, then we add the skimmed wool before boiling it, and after about 12:30 noon, it is cooled for about 12 hours, then it is rinsed in the river and dried in the sun.
- In some areas, the wool is immersed in an alum milk bath and exposed to the sun for 3 days, then rinsed before being mixed in a dyeing vessel. When the dye is absorbed, it is removed and water and cow urine added, then returned to the tank for 15 minutes, before being dried in the sun.
- One of the reasons for the quality and popularity of handmade carpets is the beauty, stability and durability of their colors. Dyeing the materials needed to weave carpets is a task that requires artistic taste, vision and precision of an industrial trainee. Carpet dyeing experts use traditional dyes from the heart of nature, many of which can be found easily, without any high costs. To create stable colors that are protected from light, air and other natural factors for hundreds of years, to become carpet pieces, a precious treasure that increases in value every year.
So where do the types of colors used in carpet dyeing come from?
Where do carpet dyes come from?
Most of the ancient handmade carpets were dyed using local plants that grow in the mountains and plains inhabited by the villagers, the master dyers dye the wool before handing it over to the carpet weavers, dyes have been used since man wanted to imitate the images found in the nature around him, and prehistoric man used Natural Pigments Therefore, pigments were naturally present in nature before they began to undergo chemical transformation...
Broadly speaking, the colors used in the dyeing industry fall into two categories: natural and synthetic, and each includes different combinations of different colours.
Colors from the heart of nature
The process used to produce the natural color was also the result of centuries of trial and error and instinctive and scientific discoveries. The result is colors with hundreds of years of durability, colors that remain healthy and of high quality after many washes, even after a lot of sun exposure, and despite the advancement of technology and science. Spinning and dyeing workshops expanded, but today it is difficult to obtain wool and color of this quality compared to the past.
Natural colors, in turn, are divided into 3 types, which are as follows:
The best choice among the natural colors are the natural plant colors which besides being of high quality, they add exceptional beauty to the handwoven rugs, as the name suggests, these colors are obtained from the natural plants such as walnut shell, grape skin, pomegranate skin etc. (As we will see in detail in the later part of this article), what distinguishes these colors is their high stability, luster, and beautiful effect, which gives an excellent result for carpet colors.
More than 100 types of vegetable dyes were recorded in ancient times. Here are the most important sources of vegetable color dyes that were used to make carpet dyes:
Madder plant (Rubia tinctorum)
Or madder, a type of perennial herbaceous plant, a plant that grows in the Mediterranean region, North Africa and some parts of Asia, and its first origin dates back to the Near East and the Caucasus, and the stem of this plant contains small thorns and reaches a height of about 2 meters. The leaves of this plant are oval, pointed and long, whether they come out in clusters or in the form of an umbrella from the side of the stem. The madder flowers are small and yellow-green. The roots of the madder produce a red dye that has been widely used for thousands of years in dyeing.
The madder plant also known as the "golden tree" was a particularly desirable source for the manufacture of dyes, and this plant was one of the most important ancient plant colors for making a natural dye for carpets in particular. Madder plant, a brick red color can be produced from it, and with time, this color becomes thicker, and at the age of 4-5 years this plant gives us a bright red color.
The madder plant is one of the plants used in the medical industry, and the madder root contains glycosides called ruberic acid, alizarin, purpurine, rubiarin, bacterial substances, resin and calcium.
Saffron is considered the most expensive type of spice in the world, and it has extraordinary properties. It is a perennial plant that grows up to 30 cm in height. From the middle of the base of the stem comes out a number of narrow and long leaves. .
The best saffron is obtained from the stigma, which is the reddest part. The color of the stigma, which depends on the amount of carotene and lycopene in it, ranges from bright red to pale orange. This plant grows well in subtropical regions or areas with mild winters and hot, dry summers. It is one of the plants of high value in Iran, as it is exported to all parts of the world at exorbitant prices. Saffron is resistant to cold because its growth period coincides with autumn, winter and early spring.
Saffron is used in the preparation of various ingredients, whether edible, industrial, medicinal, or cosmetic. It is mentioned in myths and stories that in ancient Greece the color of saffron was a famous royal color, and now its use has led to the production of special colours. At the same time, saffron was used to dye Valuable fiber, and given that saffron is a rare and expensive plant that is not widely cultivated, and its quantity and harvest are less than other products around the world, its dyeing is considered to be of a high price.
Yellow and reddish-violet colors can be extracted from saffron, which can then be mixed and extracted from its color derivatives, which makes us get the warm and pleasant colors from this gentle plant, and since saffron is a valuable plant in the dyeing industry, its use in making dyes for carpets makes the products of this The craft is expensive, and interestingly, the weaving of saffron into the weft of handwoven carpets gives off a pleasant scent, and this can help the carpet weavers to have a pleasant experience while working on the carpets.
The characteristic of dyers
A type of herbaceous plant from the cabbage family, which grows wild in southeastern Europe as well as in Central and South Asia. It was used as a medicinal plant and as a dye by the ancient Greeks and Romans. It was widely cultivated during the Middle Ages and the Renaissance in Europe to produce blue dye. Extracted from its leaves, before being removed from the foreground by the blue indigo plant, then by synthetic dyes.
The color of indigo blue
Among the other most well-known natural colors, which were used to extract the dyes for woven carpets is Deya, an ancient dye. There is evidence of the use of indigo from the third millennium BC, and possibly much earlier, and is derived from the "indigo blue" tree of the same name (Indigofera ) . tinctoria), and material is obtained from this bushy tree of the legume family, and it can reach a height of 1.20 meters and produces small flowers of a pink color, and its name comes from the Latin word indicum which means “from India”, and it was given this name by The Greco-Romans brought the plant back from India, where traces of cultivation dating back more than 4,000 years can be found, and it has been used in dyeing since ancient times.
By the nineteenth century, another turning point occurred in the history of using natural indigo in the dye industry, and natural indigo production could no longer meet the requirements of the clothing industry, and research began on industrial indigo. In 1897 synthetic indigo was launched, and in 1905, Bayer won the Nobel Prize in Chemistry for his work on organic dyes, including indigo.
Sure, of the plant carpet color options we've reviewed so far, turmeric is the most well-known option that doesn't need much introduction and introduction, but the point to note is that, in addition to the yellow color it produces, turmeric can offer other different colors such as Greenish yellow, green and orange, and the dye extracted from turmeric must be mixed with white alum as a dye (a substance used to fix the color of the fibers).
The color of the onion peel
Onion peel color is one of the most familiar choices that almost all of us know, in the manufacture of vegetable dyes, and part of the onion peel dye is found in the thin skin and is obtained from it a copper, orange, onion and aubergine color, and agricultural products such as red onion peel are used to dye natural fibers such as wool Not only does this help in recycling natural food waste, but it is also economical and inexpensive.
Pomegranate is one of the fruits whose seeds are often red and sometimes white, and the color of its peel is almost red, black or yellow. This fruit is grown in a few countries in the world such as Iran, Afghanistan, Pakistan, Iraq and Turkey, and pomegranate seeds are used in vegetable dyes for carpets, in addition to pomegranate The same, wild pomegranate peel can also be used to prepare the color.
There is no doubt that many know the medical uses of pomegranate peel, but few of us know that colors such as cream, yellow, brown and even black can be obtained from pomegranate peel, although dyeing with this substance does not require the addition of a substance during dyeing to achieve color stability and increase dyeability, but To get a good result, it is best to combine the fibers with white alum and also use sodium carbonate.
This plant grows mostly in humid and northern regions and is used as food. The buds of the plant are among its components of the pigment known to the makers of natural dye. It is picked in the spring, and gives the raspberry a gray color.
Al Resida (Balayhaa)
They are herbaceous plants with fragrant flowers in general, and this genus produces about fifty species annually, and its homeland is North Africa, Europe and West Asia, and it is used in the manufacture of carpet dyeing and ink, and various yellow colors are obtained from it, such as golden yellow, cloudy yellow, and transparent.
It is a tall red tree, and the dyeing material for this plant is hematine, and the red color is extracted from it, which is used in dyeing wool and silk, and it is used to prepare the purple color also often.
This plant grows mostly in humid areas and in northern Asia, and its pigment is found at the tips of the plant's branches, from which the yellowish-green and gray color is obtained.
Walnut is a large tree with very strong wood. The green skin of the fruit of this plant is used for dyeing. Once the fruit is ripe, it is separated, dried and used for dyeing. It can be used to create different shades of color from light brown to black and gray. This peel gives beautiful creamy and brown colors in specific proportions. , but with substances such as black alum, we can get a black color, and in combination with iron sulphate, it gives a gray colour.
The mulberry tree grows in temperate and warm regions, and its fruits are edible, and its leaves contain colored substances, and although the amount of formula in it is small and limited, it produces a pistachio green color.
This edible plant contains a large quantity of a substance which is used to obtain a tan to brown dye, and when mixed with ferrous sulfate it gives a dark brown and purple colour.
A genus of plants belonging to the aster family, there is a pigment in its flower, which gives us a reddish-yellow colour.
Or kings fruit, the fruit of the bright red cherry tree is used to obtain the red colour.
The yellow color is obtained from the skin of grapes such as saffron, and it is also a raw material for the preparation of green, garlic green, and lemon yellow, so the skin of grapes is a natural yellow coloring matter.
It is a thorny tree and also belongs to the group of flowering plants. This tree is also used to make natural dye, and its leaves and bark are used in medicine as a medicine. Its wood is also used in the dyeing industry to obtain purple, blue, black and gray colors because it contains hematite and hematoxylin. Boiling the wood of the tree and turning its sap into crystals or powder, and against the light, the fastness of the purple dye extracted from it is very high and excellent.
On the other hand, we can mention the plant color method used in the production of some carpet dyes:
The marine color is prepared by mixing indigo with water.
The black color is obtained by boiling pomegranate peel and mixing it with black alum and indigo.
The pistachio green color is obtained by boiling the leaves of willow trees, apples, and white alums.
Yellow limes are prepared by boiling dandelion (macadamia) leaves in an alum mixture.
The orange or golden yellow color is prepared by boiling the leaves of tube herb and dyeing madder and adding turmeric and pomegranate peel.
The red color is prepared by boiling the ashes of the dyed madder wood with white alum and adding water and ox urine.
Some animals can help us produce the colors used in dyeing, and the dyes of these animals are not only used in the carpet and textile industries, but also in the food, care and cosmetic industries. Here are the most important sources of the most common animal dyes:
Mankind has known it since the beginning of history, and man obtained the natural red color from its body, and this insect secretes a substance similar to gum, and the colors obtained from red seeds are also called varnish.
There are many types of this insect, and some of them live on a type of aloe vera plant, so cactus fields are also established in the places where this insect grows, and there is another type of it that lives on some types of oak trees and sometimes their number increases so much that the branches of the tree hide Under lumps of this insect.
Purple Murex (Hexaplex trunculus)
Known as the pigment murex, it is a type of sea snail that is used to make a purple dye. The native habitat of this animal is around the Mediterranean Sea. At certain times of the year, the rocks are covered with the shells of this type of crustacean, and these snails are removed one by one and the Squeeze it slowly and gently so that the dye comes out of the gland near the respiratory tract, then the snails are returned to the beach for the dye to be taken from them again.
In the past, this dye was considered expensive due to the difficulty of catching the Murex, and the violet color taken from the dye Murex is no longer used in carpet dyeing in Iran today, but is still used in some Mexican coasts.
Certain minerals and their compounds can produce high-quality colors that are used in many industries. As the name of this group of colors suggests, these colors are obtained from naturally occurring mineral compounds, such as iron oxide (yellow and red ochre), yellow lead oxide (dead stone), and blue Heavenly.
Here are the main natural mineral colors used in the carpet dye industry
It is a double sulfate of potassium and aluminum that dissolves in water and does not dissolve in alcohol. It has different types, and its use in carpets is very old. Its excessive use in dyeing leads to wool tangling and sticking... When using white alum, it is preferable not to use heavy water if possible. Because heavy water causes sedimentation and reduces the strength of alum, and for this reason, when dyeing with white alum and using heavy water, it is preferable to use Chrome Dutar to dilute it.
Black Alum (double iron sulfate)
We use this type of alum in cases where we want the desired color to be dark (black) because it darkens the colors. It should be noted that when using black alum, it should be used sparingly and the stay in the soak should be short.
Iron alum or iron sulphate is called green alum because of its green colour. It is used to prepare different shades of green.
It is one of the colored minerals that are used in the preparation of pale violet colors , and one of its disadvantages is that it reduces the resistance of the fibers, and caution should be exercised when using it. The roughness and fragility of the fibers, so this must be taken into account when using it.
Many plants and animals have been widely used by man to obtain dyes and to give us the rare and alluring colors of carpets, such as snails, beetles, all kinds of flowers and seeds, pear leaves, quince leaves, chamomile, oak leaves, linden leaves, acacia flower, catnip, rose wild, peach leaves, etc.
But the art of dyeing requires a long and painstaking process to obtain bright and beautiful colours.
Dyeing wool in the traditional way
Traditional wool dyeing steps can be divided into three main steps, the first step is to wet the strand of wool, after that the wool must be combed, and finally the dyeing process begins
In traditional dyeing workshops, large vats are used to cook the yarn with dyes, which are often made of copper, and the vats heated by direct heat of the flame are ready to cook the required textiles.
In order to fix the color on the threads, it is necessary to use long-term heating methods with natural or chemical materials other than dyes.
In this method, the wool is first treated with a special salt, and it is necessary to know that the salts of aluminum, iron, tin, and copper are color-fixing materials. In fact, stabilizers determine the intensity of the color.
It can be concluded that the method of dyeing the carpet yarns is effective in forming different color spectrums, to finally come to the stage of drying the woolen yarns.
The art of natural coloring requires a very delicate and complex process, the maturity of the plant used, the degree of boiling, the dosage of the coloring matter, and the nature of the water used (more or less dye) are largely determining factors of the color one wants to obtain.
On the other hand, many people believe that vegetable dyes do not meet the needs of the carpet weaving industry on a large scale, so some welcomed the introduction of industrial dyes in the carpet industry, while others showed serious resistance to this type of dye, but it cannot be denied its great role in the development of carpets. Dyes industry..
It is mentioned that in the middle of the nineteenth century, until the production of synthetic dyes, people used plants and natural dyes to make dyes for carpet fibers, and work began with industrial dyes in the second half of the nineteenth century, and the impact of the discovery of a very famous dye formula in Europe under the name "Turkish red" ( "cochineal") in 1868 seriously affected the export of natural dyes from Anatolia to Europe.
The chemical dye arrived in Asia in 1882 and the production of vegetable dyes began to decline due to the aniline dyes imported from Europe, but it can be said that thanks to the traditions of the nomadic groups, the dyeing technique with vegetable dyes was able to survive for long periods in the race towards the use of industrial dyes.
In general, two categories of industrial dyes, aniline and chromium, can be classified into this category. Artificial colors do not have the quality and stability of natural colors. Carpets dyed with artificial colors are less valuable than carpets dyed with natural colors. Due to the presence of long-term chemical compounds that come into direct contact with With the skin, these colors can cause allergic reactions, especially in children and people who are sensitive to chemicals.
Dyes made from chemical and synthetic materials are divided into:
1- Ink or aniline dyes
This group of dyes is obtained from aniline, which is cheap, and is known as ink dyes in the art of carpet weaving.
Ink dyes are of poor quality, get damaged and lose their stability when washed and exposed to light. Because of their lack of stability, they pose a serious threat to the structure of carpets. Many proponents of natural dyeing recommend banning their use, but for reasons such as their low price, they are very popular, in addition to their ease of access. , less time spent on dyeing and less awareness of the benefits of natural color.
2- The colors of potassium chromate
British chemist William Henry Perkin used potassium dichromate in the oxidation of impure aniline to obtain the first artificially prepared dye, mauve. Potassium chromate colors are a group of artificial colors. Potassium dichromate is used for the stability and transparency of the colors obtained. Of which, they are called chrome colors.
The use of these colors is similar to the effect of using natural colors and they have good fastness against washing and light, these colors have a sharp effect in the new carpet and become dull and faded in the old carpet.
Industrial dyeing stages
- At this point, the threads are wrapped loosely around the bobbins with special holes for dyeing, and it is interesting to know that these holes allow the color to penetrate into the thread, and then they are placed inside a box, and this is done in such a way that the bobbins do not stick together.
- At this stage, the bobbins are ready for dyeing, and they are brought to the dyeing room, which is the boiler, but it should be noted that before this step, the wool must be washed to remove the fat, otherwise the fat on the wool fibers will prevent the dye from penetrating properly to become complete and uniform on fiber.
- The temperature of dyeing wool is 45-50 degrees, and then the dye is injected into the main tank, and at this moment the temperature rises to 100 degrees Celsius, and the time for dyeing the yarn using the industrial dyeing method takes about 45-60 minutes.
- After this stage, by injecting cold water into the main tank, the dyers try to cool the tank and the bath space inside, until eventually the temperature reaches 75 degrees and the wool no longer returns to its original colour.
- It is necessary to quantify the pH (a measure to determine the acidity or alkalinity of a substance) of the yarn, so that if it is alkaline, the pH quantity can be neutralized with some ammonia.
- If the carpet is woven with alkaline or acidic yarns, its life will be greatly reduced because the yarns used in the warp and weft of the carpet become reactive.
- Washing with water is the last step, and this step is done to remove the acid remaining on the wool, after which the bobbins are placed in the spinner and then in the dryer.
- The drying process takes about three to four hours, and at the final stage, the spools are heated in a steam machine for 30 minutes so that the curls are removed from them.
Tools and materials needed in traditional industrial dyeing
Both traditional and modern dyeing require a set of special tools. The following are the most important tools used in the process:
- The container (vessel) or bath in which the dyeing and straightening operations are carried out must be made of a stainless and heat-resistant material. Steel or copper containers are usually used.
- A measure of weight (for weighing wool).
- Thermometer to measure the temperature of the dyeing bath.
- A stirrer made of wood and used to stir the fibers in the dyeing bath
- Graduated glass containers for measuring and removing acids and alkalis.
- Metal salts such as white alum, green alum, black alum, sodium dichromate, tin chloride, etc.
- Alkaline substances such as soda, ammonia, etc.
- Acids such as oxalic acid, citric acid, and mineral acids such as sulfuric acid and hydrochloric acid can also be used. In the past, "curdled milk" was used instead of lactic acid.
- Water that will be used continuously in dyeing must be available, and it is important not to forget that dyeing is a chemical process, and all necessary safety precautions must be taken, to avoid any problem.
Factors affecting chemical dyeing
The type of material and its properties
There are chemical and physical properties for each material (wool, cotton, silk, etc.), and a large part of the dyeing of raw materials for carpet weaving is done by affinity dyeing, and as a result, each textile fiber has an inherent affinity for a certain group of dyes, and the dyer chooses what suits them .
The use of the product in the future also determines the dyes used for dyeing, for example, in the case of dyeing carpet textile raw materials, the dyes containing the maximum amount of wash and wear resistant dye should be used, but in the case of dyeing the fibers used in curtain cloth fabric, it can be considered In dyeing that gives us more stability against rays and light.
Another factor affecting dyeing is the type of dye used in the dyeing process, and there are so many different companies that produce dyes that if the dyer does not have sufficient knowledge of their properties, he cannot choose the best dye for the desired dyeing and dyeing method.
Especially in the case of dyeing with chemical dyes, the choice of dyeing bath is very important, and the dyeing bath should be according to the characteristics of the product and the selected dyeing materials, because the dyeing of woven carpets is mainly done in a traditional pot, and the emphasis is on the use of steel, its rotation, and the proportion to the size of the product.
The most important condition for achieving the transparency of dyed raw materials is the use of suitable water for dyeing. Unfortunately, water that is not suitable for dyeing is used in many dyeing workshops. The presence of calcium and magnesium salts in this water causes the color of the fibers to fade. It should be noted that the water One of the most important tools for controlling dyeing quality.
All types of chemical dyes need heat to increase the dyeing speed and to do it in the shortest possible time. In addition to its effective role in dyeing speed, heat is also one of the tools for controlling the quality of dyeing, and it is necessary for the dyer to make maximum use of this tool for the benefit of the work.
Unfortunately, one of the problems with using a traditional hammam is that the temperature varies in different parts of the hammam.
In many dyeing baths, in addition to dyes and merchandise, cooperators or auxiliaries are needed, and these are used for various reasons, some as water softeners, others as softeners for the fibres.
Irrespective of all the factors mentioned above, the skill and technical virtuosity of the dyer plays a vital role in the quality of dyeing, as the dyer must have adequate knowledge of the chemical and physical properties of the product, the dye, the dye bath, and observe and analyze everything that happens in the dyeing process.
Professional carpet experts believe that one of the disadvantages of chemical dyes is that they are not resistant to direct light, washing and corrosive agents. Meanwhile, handmade carpets that have been dyed with natural dyes are resistant to light, wear and washing, which is one of its most important strengths.
Types of dyes for industrial fabrics
The use of colors in various industries such as the textile industry, construction, shipbuilding, handicrafts and many other branches of industry has led to the classification of different types of dyes for different purposes.
The dyeing process can be carried out at any stage of the production of the fabric, fibers, or threads, or during the finishing touches to the textiles. The color fastness of the textiles depends on two factors: choosing the appropriate color based on the material of the fabric to be dyed, and choosing the method of dyeing the fibers, threads, or cloth, while The following are the most important dyes for dyeing industrial fabrics:
Acid dyes include azo dyes, anthraquinone dyes, triphenylmethane and anthraquinone dyes, nitro-nitrous dyes, and azine and xanthine dyes.
The resistance of these colors depends on their chemical composition. The dyeing environment for this group of colors is acidic and includes sulfuric, acetic and formic acids. Dyeing is rarely done in alkaline and neutral environments.
These colors are used for dyeing protein fibers, silk, polyamide fibers, acrylic and other protein fibers, and they also create bright colors.
Alkaline dyes (basic (cationic) dyes
Alkaline, basic or cationic dyes are water soluble and mainly used for dyeing acrylic fibres, mostly used with auxiliaries (chrome), these dyes are chemicals that form an insoluble compound with dyes, their purpose is to fix color on canvas , and if chrome is used in conjunction with the primary colours; They can be used for dyeing cotton, linen, nylon, polyester and acrylic. Unlike acrylic, base dyes are not very suitable for dyeing other fibres, because they are unstable against light, washing and perspiration, so, in general, they are used in processes where acid dyes are applied to textiles after they have been dyed.
These colors are transparent colors and are produced in red, blue, green and purple colours. They do not have good light resistance. Examples of these colors are crystal violet and malachite green. These dyes are presented chemically in the form of salts for dyeing fibers.
These colors form a wide range of dyes including indigo, sulfur and anthraquinone dyes which are insoluble, which are regenerated by sodium hydroxide and sodium hydrosulfite, and are used for dyeing cotton, wool and silk fibres.
Sulfur dyes are insoluble, and they can be dissolved with the help of caustic soda and sodium sulfide. Dyeing with these dyes is done at a high temperature and with the help of a large amount of salt. The presence of salt in them causes the color to penetrate the fibers. After dyeing the cloth, the cloth is exposed to air or oxidized using chemicals from In order to create the desired color tones on the fabric, the dyes and chemicals remaining on the fabric are removed and disposed of by washing. These colors have good fastness against light, washing and perspiration and are mostly used for dyeing cotton and linen fabrics.
Sour dyes or chromium dyes are called acidic, and in the dyeing bath or after the completion of the dyeing process, sodium or potassium bicarbonate is used with it, and this is done in order to benefit from the chromium binding function. These colors are mostly used for dyeing wool; Because their use in the treatment of wool stabilizes the color of the fibres. In addition, these dyes are also used in the dyeing of cotton, linen, rayon and nylon, although they have less effect on these types of fibres.
Disperse dyes do not dissolve in water, these dyes are in the form of very small granules and disperse in the form of a paste or powder in the water, these particles dissolve in the fibers and give them color, these dyes were originally produced for dyeing cellulose fibers, but now they are also used for dyeing nylon and fibers acrylic.
These types of dyes do not contain sulfonic groups that make the color soluble in water. It is used as a solvent to dissolve color from organic solvents such as alcohols, esters, fats, waxes and oils. These dyes are mostly used for dyeing polyester.
Direct dyes are used for dyeing cellulose fibers without the use of concentrates. They are used for dyeing wool, silk, nylon, cotton, rayon, etc. These colors are not very bright and have little wash-fastness, although they have relatively good lightfastness.
These include ozone insoluble dyes and derivatives of naphthalene and diazonium salts, which are used to dye cotton fibers.
It is also called ice color or magic color because it needs low temperature and after conjugation the color is produced within a few seconds, and one of its properties is good to excellent color fastness against light and washing
Optically transparent pigments
These colors are special chemical dyes that absorb radiation in wavelengths from 2300 to 2800 angstroms (ultraviolet range) and emit light in the region of 4300 to 4900 angstroms (blue range of the visible light spectrum), which enhance textiles and control yellowing of fibers and textiles. Dyes derived from acetylene.
These materials are used in large quantities in the preparation of soaps, washing powders, and dyeing of cotton, wool, and nylon.
Reactive dyes react with the fiber molecules and form a chemical compound. These dyes either use alkaline solutions or use neutral alkaline solutions in a separate process. Sometimes, heat treatment is also used to create shades of different colors. After dyeing, the fabric is washed thoroughly with soap until the Dyes not completely absorbed and removed from the fabric, reactive dyes were originally used only for cellulosic fibres; But now these dyes are also used to dye different types of fibers such as wool, silk, nylon, acrylic and their combinations.
Textile dyeing methods
Dyes are applied to the fibers using different methods and during different stages of the textile production process:
- Mass dyeing: In this method, the fibers are dyed before spinning.
- Fiber bundle dyeing: The combed fiber is called fiber bundle, and in this method, the fibers are dyed before the yarn polishing process.
- Fabric Dyeing: In this method, small batches of natural dyed fabrics are re-dyed according to the target colour.
- Soluble Dyes or Polymer Dyes: In this process, dye is added to the base solution (which is fed to the yarn) before the synthetic filament is removed from the yarn.
- Garment dyeing: In this dyeing method, dyeing is done on ready-made products such as ready-made garments.
- Bulk dyeing: The bulk dyeing method is used to dye the fibers. In this process, the staple fiber is placed inside a closed chamber and the dye solution is passed through it. Although the dye solution is pumped in large quantities, the dye may not penetrate the fiber completely and some parts may not be dyed. The fibers are fine, however, the following spinning and blending processes blend the fibers in such a way that they are dyed uniformly, and this method is usually used to dye wool fibers.
- Uniform dyeing of the fibers: The combed fibers are called bundle fibers. In this method, bundles of fibers are wound on a reel and the solution is spread inside in a circular manner. This method results in uniform dyeing of the fibers.
- The method of dyeing the fibers after spinning: It is called yarn dyeing, and in this method, the dye penetrates the fibers into the core of the yarn, and there are different methods for dyeing the yarns, some of which are skein dyeing, bobbin dyeing, tufts dyeing...
- Coil dyeing: In this method, the yarns are loosely wound into bobbins or coiled around each other, and then hung on a ladder and immersed in a dye bath. In this way, the dye penetrates well into the yarn, and the yarns remain softer and smoother. Mostly for dyeing wool yarn and large rolls of acrylic yarn.
- Waterfall dyeing: Waterfall dyeing is similar to bobbin dyeing, but it is more economical. In this method, the thread is wrapped around a net and then immersed in a basin containing a colored solution.
- spool dyeing: the yarn is wound on spools, spindles, or similar parts, then arranged on gratings and immersed in a tank, within this tank, the paint is pumped from the outside to the inside of the spools and back to the center of the spools; This will allow the dye to penetrate the thread as much as possible, and combed cotton used in textile production is usually dyed in this way.
- Rope dyeing: This method is used to dye long fabrics, and the fabric is passed through the dye bath in the form of a rope, where this fabric rope moves through a rod on a ring, then this ring is immersed in the dye and thus the fabric is pulled forward, and this process is repeated several times until the density approaches Color the fabric of the desired color.
- Jet dyeing: In this method, the fabric is placed inside a warm tunnel, where a dye solution is sprayed onto the fabric under high pressure; At the same time, the cloth also moves along the tunnel, and during the whole dyeing of the fabric, the velocity of the solution is faster than the speed of the fabric inside the tunnel.
The most important dyes used in oriental carpets
Despite the advancement of technology and science and the expansion of spinning and dyeing workshops, it is difficult today to obtain wool and color of this quality compared to the past.
While the most common carpet colors that come to mind are shades of brown and red, blue is one of the most attractive colors to be seen in ancient oriental rugs, and strangely enough, blue didn't leave the field of carpets and rugs at any point in history. long, and this color has always had a great influence in attracting the public's attention and adding spirit to homes.
Although the use of blue as one of the common carpet colors that is very popular nowadays, it was not the case in the past, that is, blue has always been present in carpets, but not common carpets, the use of this dyeing dates back to ancient times, Most likely, the color blue was first brought to Europe from India 700 years before the birth of Christ, and this dye was still considered a rare and expensive color until the Portuguese traveler and explorer Vasquido Gama created a new sea route between India and Europe in the fifteenth century, and the blue dye was At that time, it was extracted from two main sources, indigo and wasmah al-sabbaghin.
It goes without saying that the process of producing the color of the carpet in indigo is a very difficult task, because the solution used in this work is basically colorless; The indigo color turns blue only when the fibers are removed from it and oxidized in the open air, so knowing when to remove the fibers from the solution to obtain the appropriate color requires experience and professionalism.
It is almost said that the most important color in oriental carpets is red or the color of lacquer, and this color is often prepared from the dyeing madder plant, known as the most stable red color in the world, and this plant usually grows in vineyards, and in the autumn season, when exposed For the wind, its core is separated from the husk, and this red nut is then ground in dye shops and used as a dye for the wool of oriental carpets.
In addition to pigment madder, the red color is also obtained from insects and fungi, and in India, the red color was obtained from a type of red gum, and red gum was, in fact, considered a kind of fungal plant disease that causes weakness and death of trees, where these The fungus resides in the crevices of the trunk and twigs and produces a dark colored sap, the red color obtained from a bedbug-like insect called red armenian.
In fact, the use and production of these organic colors is not as common as it used to be in the past, because products and fibers dyed with natural colors cost much more than similar synthetic products due to the great effort involved in obtaining them. However, antique handmade carpet makers are trying to preserve this historical legacy To ensure that this kind of carpet is present in every home and environment, to give us the spirit of nature in the cold and fast urban life.
If you have visited the alleys of the historical fabric of Birjand, the capital of South Khorasan Province in eastern Iran, and passed through the narrow and broken alleys of this region, and reached a neighborhood that was known in the past as the dyers’ neighborhood “Rangarzaha Neighborhood”, a neighborhood that smelled of plants and natural colors emanated from its alleys. The sound of paint pots, large pots in which natural plants are soaked to extract dyes, dyed woolen threads floating in the streets, you will discover that this profession is no longer vital in this region, but the old men of Burgundy remember very well, Rangarzaha, a neighborhood whose alleys used to smell Plants and natural colors from which the most beautiful and valuable dyes of oriental carpets are made!
The creative mind of the designers, the magic of the colors of the dyers, and the ingenuity of the fingers of the weavers, created a pattern of handmade carpets that preserved its beauty and originality even after many years, and there is no doubt that the art of dyeing has existed since the beginning of civilization and human history in the various human societies in that period, and three may have been used To five natural rich raw colors obtained from a wide variety of plants, minerals and insects at the time, and after hundreds of thousands of years, this number has reached an incalculable number of colors..
Since the middle of the nineteenth century, human research and developments in chemistry have led to the creation of thousands of artificial colors, which are considered more economical in terms of price and speed of work, which is difficult to count, and these changes and transformations, which only occurred in a hundred years, occurred in silence but were presented to us Countless natural and artificial bright colors and dyes for the manufacture of handmade carpets and various textiles.
Rubia tinctorum L. (Rubiaceae) or Madder as one of the living color to dyeing wool
Hamze Esalat Nejad, Ahmad Esalat Nejad