This can be used to make another extraction to revive or adjust the vat. This vat can be used until exhausted, or it can be combined with a fruit vat. This vat takes advantage of plant material that is rich in antioxidants. Remember that these materials are used as reducing agents, not as colourants. Spent dye matter that is no longer useful for dyeing is best. If you wish to store spent matter until you are ready to make an indigo vat you must dry the dye matter first.
Otherwise it will go mouldy. The Ferrous Vat gives a beautiful dark indigo and has the advantage of being a cold vat that keeps for months. It is good for cloth that has been printed with resist as it does not require long dips. It is a vat with a long history in many cultures.
Start with hot water — almost boiling. Add the indigo to the vat, then the ferrous sulphate, then the lime. Wait for the vat to turn yellowy-green.
Lower down in the vat, the liquid will be amber coloured. Check for the bronze surface and the dark bubbles. Begin to dye with short dips minutes. A basket is highly recommended for dying when using the ferrous vat.
If the iron in the bottom of the vat touches items being dyed it may cause discolouration. The ferrous vat gives a more stately blue, little less bright than many of the other vats and more like what might be found on a pair of seasoned blue jeans. Maiwa has a ferrous kit with everything you need to make this vat. Our first choice for a vat is usually an organic vat. However, the workhorse vat is a very dependable alternative that is quick and easy to make. If you are new to indigo you may want to make a small workhorse vat to see how a successful vat behaves before moving on to one of the organic vats.
As for all indigo vats, three things are necessary: 1 Indigo, 2 A reducing agent, 3 A base. We recommend natural indigo in powder form. Maiwa uses thiourea dioxide as a reducing agent in the workhorse vat because it has a long shelf-life and can be disposed of safely. We recommend calx calcium hydroxide as a base. There are two alternatives to calx: lye and soda ash. Lye is a strong base and as such should be treated with caution. The casual use of lye around the home studio is not recommended.
Soda ash is less caustic than lye and is a good alternative. If using soda ash the vat may reduce more slowly and may need the pH checked more often. OR — 60 g 4 tablespoons of soda ash. Caution: a mask should be worn to avoid inhaling any powders; especially lye, soda ash, calx or thiourea dioxide. Fill a 1 litre 1 quart mason jar with hot water, add the calx or lye or soda ash and stir until dissolved.
Add the indigo and gently stir for 2 minutes chopsticks work well for this. Add the thiourea dioxide and stir for about a minute. Do not close the jar. As the starter reduces, the colour of the surface of the liquid will change to a purplish violet with a coppery sheen. Below the surface the solution will change from an opaque blue to a translucent yellow-green.
This may take about 30 - 60 minutes. If reduction is slow, set jar aside in a warm room or place it in a bath of warm water for about 60 minutes. Check the stock solution to see if it is ready by dribbling some solution on the side of a white cup. If it changes from clear yellow to opaque blue as the indigo oxidizes — it is ready. The stock solution may be used immediately or kept for later up to a week.
If kept longer than a week the solution may need to be revived. This vat does not need maintained heat and so you can use a plastic container. Add the calx or lye or soda ash into the water and stir until dissolved.
This makes the vat slightly alkaline so that the reduced indigo from the stock solution does not re-oxidize when added. Add 4 g 1 teaspoon of thiourea dioxide and stir gently until dissolved.
Allow the vat to reduce for about 15 minutes. Carefully lower the jar of stock solution into the vat. Avoid pouring from above as this adds oxygen. Transfer the contents of the jar completely.
Stir to create a vortex. Then allow minutes for the vat to turn yellowish green. Check the pH. The pH of a new vat should be 11 the correct for cellulose. If dyeing protein fibres, wait for the pH to lower to This recipe can be doubled, halved, or made in any size so long as the proportions remain the same. NOTE : If using this vat in combination with other natural dyes, we recommend doing the indigo first as the thiourea particularly in a new vat may discharge some colours.
Maiwa has an indigo kit with natural indigo, calx, thiourea and printed instructions. Guide to Natural Dyes. Maiwa's Natural Indigo. Our Relationship With Indigo. Indigo Dyeing in Laos. Ismail Khatri at his indigo vat. Multi-layer indigo jacket. A reducing agent Chemically, we need to reduce the indigo to make it soluble — we do this with a reducing agent. A single length of cloth torn in two — soured on the right, not scoured on the left. Scouring Cellulose.
Cotton, linen, hemp, etc. Fill a large pot so that cloth or yarns are covered and not crowded. Scouring Protein.
Silk, wool, hair etc. Turn gently but do not agitate 4. Allow fibre to cool down slowly and then rinse in warm water. The vat is now ready to be used for dyeing. TIP - The secret of a Starter Solution Sometimes it is easier to get your vat working by beginning in a small container and then transferring it to a full-size vat. TIP - Hydrating Indigo. Tip - Dyeing with a Basket When using an indigo vat, it is good practice to keep yarns and cloth from touching any sediment in the bottom of the vat.
Eight shades of indigo on wool. Dyed using an organic banana vat. Overdyeing with Indigo If planning to overdye with indigo, we generally do indigo last as indigo can be stripped out by other processes. Indigo 2 dips. ReDucing agent Use a metal spoon to look at the liquid just under the surface. Feed your vat After a long day of dyeing, a vat likes to go to bed with a full stomach. Reviving Vats. A Reducing agent To make an organic vat, use organic reducing agents.
A Base For the organic vat we recommend using the most benign base possible. Recipes for Organic Indigo Vats We suggest that you take these recipes as a guidelines. The Banana Vat The banana vat is the most popular of the fruit vats.
For a vat of about 20 litres — 75 g 2. The Fruit Vat Review the instructions for indigo vats. The Date Vat Review the instructions for indigo vats. Blend this mixture until it is smooth. The Fructose Vat Review the instructions for indigo vats. For a vat of about 8 litres — 30 g 1 oz powdered natural indigo — 90 g 3 oz fructose — 60 g 2 oz calx calcium hydroxide Fill a 10 litre 2.
Add the fructose and stir to dissolve. Get the Fructose Kit. Add the liquid to the water in the vat. Thus, indigo dyeing process is based on repeated dipping and aeration. Dyeing machines are designed taking this point into consideration. That's why they have more than one dye pad. Basically, ropes continously take the dyestuff from the pads and are fixed thanks to air reaction.
Indigo dyeing has 3 important parameters:. These chemicals must be fed at sufficient ratio consistently. Dye pads are supported by an internal circulation system. The amount of chemicals to be fed must be constant during the process in order to avoid indigo - hydro concentration and pH value differences. This circulation system eliminates possible shade differences on fabric. What's ring dyeing? As already known, indigo dyed ropes warp yarns have an ecru core and its outer layer is dyed.
This is called "ring-dyeing". The ring-dyeing property of a rope is determined by pH value and hydro concentration. The penetration of dyestuff into fibre in a dye bath having When pH value shifts towards This drastic drop affects fabric-washing properties.
Efficiently ring - dyed fabrics would respond washing finishing better and faster. These parameters have to be adjusted according to end-product properties.
The rope turns yellow-green colour when first dipped into indigo bath. It turns to magic indigo blue as soon as it reacts with air. This legendary colour change is really worthwhile. Washing and Drying of Ropes Washing pads and drying cylinders : After iterative numbers of dipping, ropes follow washing pads in order to remove unfixed indigo dyestuff. Besides, this step has a neutralization effect, as pH value needs to be lowered because of high pH environment during dyeing process.
This step is completed reaching sufficient humidity with the help of steamed drying cylinders. Sufficient humidity ratio is important for the efficiency of re-beaming of ropes after dyeing. Main parameters of indigo dyeing:. Since reduced indigo has strong decomposition tendency, there must be excess hyro in dye bath. The preservation of reduced form is accomplished by excess hydro.
Therefore, the control of hydro concentration in dye bath solution has great importance. The amount of hydro is affects penetration of indigo dye into fiber. The best dyeing is achieved between 11,,5 pH. The penetration increases when pH is increased, darker and consistent shades can be obtained. Therefore, the response to stone-washing gets more difficult.
Dipping time 2. Penetration 3. Oxidation airing time. The amount of dyestuff picked up 2. Process Control: Foxboro Automation System. Foxboro automation is a system used to control various and countless process data in indigo dyeing. The system is designed to check every individual step in process and alert in case of any disorder.
The set values are loaded into system according to a certain dyeing recipe. The second is when the dye is applied to the yarn, and the third is when the dye is eluted into the wash water during the initial stonewashing or wet processing of the fabric. This last route typically occurs during the production of denim fabric. Much of the need for indigo is being met with other types of blue dyes and today most of the indigo used by the world is made out-side the United States.
Researchers are concentrating on new methods of indigo manufacture that are more environmentally friendly. One promising future method involves using biocatalysts in the dye reaction process. Indigo dye may be one of the first high-volume chemicals made through a biological route. Genencor International, of Rochester New York, is evaluating a process to produce indigo using biotechnology. According to Charles T. However, at this time the technology is expensive and production costs could be prohibitive.
Genencor is seeking a major market partner to work with them in the development of this new technology. Manufacturers who use indigo in dying operations are also seeking to improve their use of the dye. Compared to traditional methods of stonewashing fabric dyed with indigo, their new process uses few, if any, pumice stones which help give the fabric its faded look.
Therefore, pumice stone handling and storage costs are reduced, along with time required to separate pumice from garments after stonewashing. It also uses much less bleach. Therefore, this new process not only reduces garment damage, but also reduces waste produced by the stones and bleach.
Kirk, R. Othmer ed. Wiley-Interscience, John Wiley and Sons, Guilbaut, G. McCurry, John. Rotman, David, and Emma Chynoweth. This will minimise any crocking onto light coloured clothing! While dyeing with indigo does require a fair amount of preparation and care, the results you can achieve by playing with shibori techniques can be quite spectacular!
I often choose to use viscose, as opposed to cotton, as it remains soft after dyeing, making it ideal for a scarf or something similar.
Viscose, like cotton or linen, is a fabric made from natural cellulose fibres and as such, takes the indigo dye quite well. Cotton can be used to more hard-wearing items like pillow cases or bags, but you can also use wool and synthetic fibres. Some people might avoid using synthetics as the indigo can have trouble binding to these fabrics: they tend to have a tighter weave so the indigo molecules have less chance of getting lodged between the fibres.
However, dyeing synthetic fabrics is not impossible and can give interesting results. Part of the fun and charm of dyeing with indigo is in the experimentation! Denimhunters is a knowledge portal for denim enthusiasts and newcomers. Start your hunt here! Felix Pecarski is a denim enthusiast from London who now calls Stockholm home. Save my name, email, and website in this browser for the next time I comment. Sign me up for the newsletter!
Looking for quality jeans and other well-made essentials? Always add the soda ash and sodium dithionite into the water. Never pour the water onto the soda ash or sodium dithionite! Always wear gloves and if possible, protective eyewear as soda ash is highly alkaline and will irritate if it comes into contact with your skin and eyes.
The end result should feature high contrast waves like these! May 26, Ruedi Karrer 4 years ago Reply. Congrats Thomas to your awesone indigo article!! Very interesting and inspireing.
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