In the past, indigo, woad and pastel (a variety of woad) was used to dye wool and cotton fabric blue. Indigo and woad dye are different from other natural dyes because the dye isn’t water soluble: you have to make a vat. Today, chemicals are used to make a quick vat. In the past, however, it was usually a fermentation vat using different ingredients like bran, madder, yeast, weld, molasses, urine, potash and lime.
Because I’m growing fresh woad leaves, I’m researching historical indigo and woad dye recipes. I’m particularly interested how cotton fabric was dyed with fresh woad leaves in the past. Because if you want to dye vegetable fibers like cotton, linen or nettle, you have to prepare a different vat than if you want to dye animal fibers like wool or silk.
‘Goods are most frequently dyed blue with indigo by means of a solution of white indigo (reduced indigo) in an alkaline fluid, the goods being blued by exposure to air […] The same vats are not equally adapted for wool and calico [cotton fabric], there being […] a wide difference in their composition.’ (Manual of Chemical Technology, 1892)
How To Dye Blue With Indigo Or Woad – 8 Historical Dye Recipes
Urine Indigo Vat (With Fresh Urine)
‘To dye a blue or sky colour. Take a sufficient quantity of urine, and four ounces of indigo, pound it to powder, and then dissolve it in the urine by a gentle heat, being close covered; then try its strength with a little bit of wool or flannel, and if it does not dye well, let it stand longer, until it is of a good colour. […] before you put in your wool […] put a pint of yeast into your liquor, and it will make the dye the better […]
Urine Indigo Fermentation Vat (With Stale Urine)
To dye an excellent blue colour. Take of stale urine a sufficient quantity, and four ounces of rock indigo, set them to soak in a good heat, till the indigo is dissolv’d; then put to it a pint of slack’d lime, and a pint of new yeast, mix them well together, and let them stand a quarter of an hour very hot; then stir it, and enter twenty yards of broad-cloth, and handle it over and over, and then take it out and wash it. If it is not deep enough, heat the vat and put it in again. […]
Quick Woad Vat
To make a substantial blue dye. Take water a gallon, one pound of woad, infuse it in a scalding or almost boiling heat for twenty four hours; then put into it wool, cotton, stuffs, flannel, or cloth of a white colour.’ (Dictionarium Polygraphicum, Or, The Whole Body of Arts Regularly Digested Containing the Arts of Designing, Drawing, Painting, 1735)
Woad Fermentation Vat (With Lime)
‘In most dye-houses the pastel is pounded before introducing it into the vat. Some practical men, however, maintain that this operation is injurious […]
When the bath has undergone the necessary ebullition, the pastel should be introduced into the vat, the liquor decanted, and, at the same time, 7 or 8 lbs. of lime added, so as to form an alkaline ley, which shall hold the indigo in solution. Having well stirred the vat, it should be set aside for four hours, so that the little pellets shall have time to become thoroughly soaked, both inside and out, and thus be prepared for fermentation. Some thick coverings are to be spread over the vat, so as to preserve it from contact with the atmosphere.
After this lapse of time, it is to be again stirred. The bath at this moment presents no decided character; it has the peculiar odour of the vegetables which it holds in digestion; its colour is of a yellowish-brown. Ordinarily, at the end of twenty-four hours, sometimes even after fifteen or sixteen, the fermentative process is well marked. The odour becomes ammoniacal, at the same time that it retains the peculiar smell of the pastel. The bath, hitherto of a brown colour, now assumes a decided yellowish-red tint. A blue froth, which results from the newly liberated indigo of the pastel, floats on the liquor as a thick scum, being composed of small blue bubbles, which are closely agglomerated together. A brilliant pellicle covers the bath, and beneath we may perceive some blue or almost black veins […]
in this state we might even dye wool with it without any further addition of indigo […] When the stuff or cloth has been immersed for an hour in the vat it should be withdrawn […] and hung up to dry […] Then we may replunge the stuff in the vat […]
Indigo Fermentation Vat (With Bran & Washing Soda)
German Vat. […] Having filled the copper with water, we are to heat it to 200°Fah.; we then add 20 pailsful bran, 22 lbs. of carbonate of soda, 11lbs. of indigo, and 5 1/2 lbs. of lime, thoroughly slaked, in powder. The mixture is to be well stirred, and then set aside for two hours; the workman should continually watch the progress of the fermentation, moderating it more or less by means of lime or carbonate of soda, so as to render the vat in a working state at the end of twelve, fifteen, or, at the most, eighteen hours.’ (A Manual of the Art of Dyeing, 1853)
Indigo Vat For Cotton Fabric
‘Generally all calicoes [cotton fabrics] are dyed blue by means of the cold lime and copperas vat. The materials used are lime, ferrous sulphate, ground indigo, and water. The chemical action consists, in the first instance, in the formation of calcium sulphate and ferrous oxide; the latter substance, having a considerable affinity for oxygen, removes an atom of it from the blue indigo, converting it into white, which dissolves in the excess of lime, and is ready for dyeing.
The proportions are as follows: -9000 gallons of water, 60lbs. of green copperas, 36lbs. of ground indigo, and 80 to 90lbs. of slaked lime. These are stirred up together every half-hour for three or four hours, then left twelve hours to settle, well raked up again, and as soon as the vat has subsided it is ready for dyeing.’ (Manual of Chemical Technology, 1892)
Woad Fermentation Vat (With Madder & Bran)
‘I placed in a copper a small vessel containing fifty quarts, and filled two-thirds with a liquor made of river water, one ounce of madder, and a little weld, putting in at the same time a good handful of wheaten bran and five pounds of woad.
The vat was well raked and covered; it was then five in the evening; it was again raked at seven, nine, twelve, two, and four o’clock; the woad was then working […] Pretty large air bubbles formed themselves, but in small quantity, and had scarcely any colour. She was then served with two ounces of lime and raked.
At five o’clock a pattern was put in; which was taken out at six, raking her; this pattern began to have some colour, another was put in at seven, at eight she was raked, and the pattern came out pretty bright […] at ten she was raked, and one ounce of lime was added,
because she began to have a sweetish smell […] I chose rather to put her back to the next day […] and for that purpose, I put one ounce of lime, which kept her up till nine in the morning: from time to time patterns were put in; she was served with a liquor composed of water, and a small handful of bran. She was raked, and patterns put in from hour to hour’ (The Dyer’s Assistant in the Art of Dying Wool and Woollen Goods, 1800)
Indigo Woad Fermentation Vat (With Yeast)
‘The woad or pastel vat according to Homassel. – To set this vat, it is useful to employ either putrid water, or an old vat of madder, to accelerate the fermentation of the woad;
but if you have not these, proceed thus: The day before you set your vat, grind twelve or fifteen pounds of woad, and having put it in a basket, pour hot water upon it to moisten it. Let it thus remain till it comes down to the warmth of leaven. Then take four ounces of yeast, and mix it with warm water, add it to the pastel or woad and stir it in; cover it so that it may retain its heat. In a short time the fermentation begins, and the woad becomes of a fine green colour; this serves as a ferment or leaven for the vat. After this, common water will answer the purpose, which when boiled for a short time is emptied into the vat, but the woad must not be put in while boiling, otherwise it will set, and be injured.
Break the lumps of three or four balls of pastel (they are about one hundred and fifty pounds each) and put them in the vat; and when the heat is sufficiently moderated not to burn the leaven or ferment prepared the day before, and which by this time ought to be of a fine green colour, and in a state of lively fermentation, put this in also; stir the vat and cover it;
but you must put your ear close to it from time to time, to observe the gentle noise of the fermentation within, which should not be permitted to go on too hastily; this may be prevented by throwing in a small wine glass full of slacked lime each time you stir the vat, for this absorbs part of the carbonic acid gas which is extricated; this should be done occasionally till the moment when the blue tinge appears; at which time, and while the fermentation is yet lively, add to the vat ten pounds of well ground and sifted indigo, and stir the vat well, then let it rest covered, during four hours. After this, try the vat with small specimens of woolen, till you see them come out a full green and turn blue in the air.’ (A Practical Treatise on Dyeing, and Callicoe Printing, etc, 1815)
Natural Dyeing With Woad & Indigo – Tips & Tricks
Wooden Or Copper Vessel Covered With Blankets
‘The solution of indigo white is prepared in a vessel […] made of wood or copper […] covered with a wooden lid […] Over this lid are spread some thick blankets. Without this precaution the bath would come in contact with the atmospheric air; a portion of the indigo would absorb oxygen, and become precipitated. There would also be a great waste of heat. […]
A most necessary operation, and one which has to be frequently repeated, consists in stirring up the deposit of vegetable and colouring matter which is formed in the vat, and intimately mixing it in the bath. For this purpose we employ a utensil called a rake, which is formed of a strong square piece of wood set on a long handle. […]
Adding Bran, Madder, Weld, Hay, Yeast & Lime To The Woad Vat
Bran is apt to excite the lactic fermentation in the bath, and should, therefore, not be employed in too large a quantity […] The weld is rich in oxidizable principles; it turns sour, and passes into the putrid fermentation with facility. […] Sometimes weld is not added at all.’ For the woad vat ‘we must […] use a larger quantity of lime, since the woad contains no ammonia resulting from previous decomposition, such as we find to be the case with the pastel’ (A Manual of the Art of Dyeing, 1853)
‘In setting the vat, the old liquor of a spent madder copper may be used to save madder, which like the weld is of no use as a colouring, but only as a fermenting ingredient. […] I think weld might be superseded by common hay.’ (A Practical Treatise on Dyeing, and Callicoe Printing, etc, 1815)
Fermentation Vs. Lime
‘the skill in treating the woad-vat, depends on the proper addition of lime to prevent the too hasty fermentation of the vegetable substances employed to disoxygenate the indigo, which would destroy the colouring matter; and to dissolve a part of the colouring matter so disoxygenated. The lime is gradually precipitated in the form of pulverized limestone by the addition of carbonic acid proceeding from the gradual fermentation of the madder, the bran, and the decoction of weld. Hence the necessity of now and then adding a small quantity of fresh lime, to renew the necessary solvent. […] take care that the fermentation does not proceed too wildly, stop it now and then with a small handful of lime. The fermentation ought to be nearly confined to the bottom; if the liquor be ill coloured, and the working of the vat throws gross particles up to the top, it is a sign it works too strongly, and is to be corrected (but cautiously) with small quantities of lime; for if so much be thrown in as to stop the fermentation, you will get no colour. Should this happen, you must refresh it with some woad, set to ferment with yeast – or with tartar and bran – or with madder’ (A Practical Treatise on Dyeing, and Callicoe Printing, etc, 1815)
Adding More Water To The Woad Vat
‘When the specimens or sample-pieces which have been an hour in the liquor, exhibit the colour required, boil some river water and fill up the vat. This will not weaken the liquor; on the contrary the admixture of boiling water, will enliven the fermentation, and increase the depth of colour.’ (A Practical Treatise on Dyeing, and Callicoe Printing, etc, 1815)
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