EIGHTEENTH CENTURY PAINT MATERIALS 
AND THE PAINTERS CRAFT AS PRACTICED IN LOUISBOURG

TRAINING MANUAL

BY

A. Storm

May 1982

(Fortress of Louisbourg
Report H G 05)

Chapter III

Wood dyeing is of very great importance for cabinetmakers, since it is by that means that they succeed in giving their woods the different colors necessary for them to represent all sorts of objects, such as fruits, flowers and animals. However, cabinetmakers have always made a very great secret of the composition of their dyes, in order to keep the enjoyment of it for their own exclusive enjoyment, and not to increase too greatly the number of workers; when the fact that most of the compounds used by the cabinetmakers of old have not come down to us, or else have been poorly imitated. The five primary colors are blue, yellow, red, brown and black; each of these colors is given by different drugs, (elements), which are mixed together to produce the secondary or compound colors.

The blue for dyeing wood is made with indigo diluted in oil of vitriol and placed in a sufficient quantity of water.

Yellow is made with barberry, yellow earth and saffron mixed together, or else simply with weld.

Red is made with dyer's wool or else with a decoction of Brazil wood mixed with alum.

Brown is made with walnut peel.

Black is made with India wood, gall nut and green copperas.

Before entering into the details of the composition of the various dyes, I shall give a general idea of the drugs of which they are compounded, in order that carpenter-cabinetmakers may be less subject to be misled when they buy them.

Indigo is a species of dark blue ash from the leaves of a plant which grows in America and Hindustan, and is sold in small pieces. Good indigo is moderately hard, floats on the surface of water and is flammable; it is of a fine deep violet or blue color, and through the inside are scattered silvery flakes, which appear reddish when rubbed on one's fingernail. Indigo is preferable to any other drug for dyeing woods, because it is a powder whose extremely fine and thin parts easily enter the pores.

Oil of vitriol is the last spirit which is drawn from vitriol. This acid liquor must be very concentrated and absolutely free of aqueous parts in order to make a fine blue color, as I shall explain in the proper place.

Barberry is a small shrub whose berries and root bark yield a yellow dye. Barberry from Candia has very yellow wood, and passes for being the best.

Weld is a fairly common plant in France. It is boiled in water to extract a yellow liquor which, mixed with a little alum, dyes very well. Dyers prefer the smallest weld, with a reddish color.

Yellow dyeing is also done with the yellow wood. Yellow earth is nothing other than the yellow ocher used by painters.

Saffron is a plant which grows in France, especially in the Gâtinois; it is the pistil of the saffron flowers which gives these small reddish -or orangey - filaments, which are sold under the name of saffron, and yield a golden-yellow dye. Good saffron is fresh, with a penetrating odor and a shiny color; it feels greasy to the touch and sticks to the hands.

Alum is a fossil and mineral salt which is much used in dyeing, to prepare the materials which are to be dyed or to strengthen the colors, all of whose particles it holds in position by virtue of its astringency. The best is Roman alum, which is white and transparent in roughly the same way as crystal.

Dyer's wool is sold by wool merchants. When it is boiled, a pink decoction is obtained. The depth of the color varies with the amount of water used in relation to the quantity of wool.

Brazil wood, here I would only say that a decoction of this wood yields a light red color bordering on orange, and that the color is deepened by adding a little alum. The Brazil wood from Pernambuco is the best; it is available in chopped form from grocers, who sell it by the livre.

Walnut peel is the first envelope around the nuts. It is removed before the nuts are fully ripe, and is boiled in water to extract a brown or brownish dye from it.

India wood, yields a deep red decoction which dyes black; and when alum is added, it dyes violet.

Gall nut is a species of excrescence which is found on the soft branches of a species of oak called rouvre (English oak). The most highly prized gall nuts come from the Levant; the best are the heaviest ones, with a spiny surface. Both green and black ones exist; they are both used for dyeing black.

Green copperas is a species of vitriol which is found in copper mines. It is the most powerful of acids. It corrodes iron and copper. In the parts to be dyed, it makes an infinite number of little holes into which the dye penetrates. Copperas is also called Roman or English vitriol, according as it comes from one or the other of these countries. Vitriol is made in France which is said to be just as good.

Copperas is light green in color; the clean and shiny kind should be selected.

Verdigris is also used in dyeing woods. It is a green rust scraped from copper plates. Good verdigris is dry, pure and deep green in color, and is full of white spots.

Such roughly, is a description of the ingredients commonly used for dyeing wood. We shall now turn to how they are employed.

How To Dye Woods Blue

Blue is prepared from indigo and oil of vitriol in two ways, hot and cold. But blue for wood is prepared cold in the following way.

Take four onces of the best quality vitriol, namely vitriol which is free of aqueous parts, and pour it into a one-pinte bottle onto an once of indigo reduced to a very fine powder; then fill the bottle with water, or nearly fill it, at least; stop it very carefully and lute the stopper with wax. Then let it steep for five or six weeks, at the end of which time this dye can be used; one can make it stronger or weaker by putting an appropriate amount of water in it, taking care, however, to add a little oil of vitriol to make the dye more mordant. When the dye has reached the strength required, put it in a vessel of glazed earthenware or stoneware, and let the woods soak in it until they have been entirely penetrated with it. This will sometimes take two weeks, even a month, depending on the hardness and thickness of the woods which, however, can scarcely be more than one ligne in thickness.

Cabinetmakers ordinarily use a stoneware butter pot for dyeing woods. This is very convenient, because a vessel of such shape will take pieces of fairly great length without it being necessary to use a very large amount of dye.

It is very easy to know when the inside of the wood has been penetrated; merely cut into the wood a little at one end, at two or three lignes from the extremity; and when the pieces to be dyed cannot be cut in that way, put with them another piece of like quality, on which you can do tests to determine the degree to which the other pieces have been dyed.

How To Dye Yellow

Cabinetmakers dye yellow with barberry, yellow earth and saffron, which they boil together; then they soak the woods in it until fully dyed. The proportion of these drugs is two litrons of barberry to six sons of yellow earth and four sous of saffron.

A decoction of weld gives a very fine, fast yellow, and the woods are soaked in it in the usual way. When a little verdigris is added to this decoction, a sulfur-colored yellow is obtained. Saffron steeped in brandy yields a very fine golden yellow.

How To Dye Red

Red is ordinarily made with Brazil wood, which is boiled with six sous of alum for each livre of wood. This red is fugitive; and as it is rather orangey than red, one can instead use dyer's wool, which yields a very fine red bordering on pink, which is deepened by putting the pieces that have already been dyed in the liquid from the wool into the dye of Brazil wood mixed with alum; which then gives a very fine red whose depth varies with the length of time the pieces have been left in the Brazil-wood dye.

The wool dye is made very easily; it is simply a matter of boiling the wool dyed for that purpose until it yields a fine red decoction, taking care to avoid boiling it too long, for then the wool will take back the color it first released.

The proportion of dyer's wool to use is one livre to four pintes of water for the first boil, which can be followed by a second and even a third boil, until the wool yields no more color.

A decoction of Brazil wood without alum yields a yellowish red, which is so sometimes quite beautiful; it is called capucine.

A decoction of India wood is very red, but it makes a blackish dye, which can be made into a very beautiful violet by adding alum of Rome, as I shall explain hereafter.

How To Dye Brown, Black and Gray

Brown dye is made with a decoction of walnut peel which can be stronger or weaker, as seems proper, by adding a little alum.

A beautiful black is made by first dyeing the woods in a decoction of India wood (or Campeachy wood, which is the same thing); and when this first dye has dried, they are soaked in a decoction of gall nut to which some green copperas or vitriol of Rome has been added; sometimes a single dye is made of these various ingredients, the proportions being one part nut gall to one part vitriol and six parts India wood, all boiled together; the wood is soaked in it until penetrated.

Gray dye is made with a decoction of gall nut in which a smaller quantity of green vitriol than for black dye has been dissolved; so that the more copperas is used, the darker the gray becomes. The usual proportions are one part copperas to two parts gall nut.

How To Dye In Compound Colors

The ordinary green dye of cabinetmakers is usually made with the same ingredients as for blue, to which barberry is added in a quantity proportionate to the depth of the green desired.

A very fine apple green is made by first dyeing woods blue in the usual way, and then soaking them in a decoction of weld for a period of time appropriate to the strength of the green desired.

Violet is made with a decoction of India wood to which alum of Rome has been added; one can vary the depth of the violet by first dyeing the wood pink, and then blue, which will produce a light violet.

If on the other hand a brown-red bordering on violet is desired, the woods are first dyed in the decoction of Brazil, then in the decoction of India wood.

Compound dyes can be obtained in all imaginable shades by dyeing the wood a primary color, then another one more or less deep in color, so that the dye that results from the two colors resembles each of them to some extent; this is quite possible to do, since one has the power to strengthen or weaken the primary dyes as much as one seems fit, either on account of what the form of the object one wishes to represent requires, or on account of the different qualities of the woods, which take the dye to varying degrees and strengthen or weaken the color of it - a matter deserving careful consideration and requiring great attentiveness and experience on the part of cabinetmakers.

In general, all the dyes of which I have just spoken are applied in cold baths; it is not that many of them cannot be used hot, but rather that as it takes a very considerable time for the same dyes to penetrate the inside of the wood, it is not possible to use them hot; in addition, dye used cold has a great deal more shine on wood than when it is used hot.

Such, roughly, are the details of wood dyes, at least those used by most cabinetmakers, and which I myself have used in the tests I have made with them; these tests have worked fairly well for me, but have not been followed by a sufficiently great space of time for me to be sure of the success of my attempts.

Cabinetmakers not only dye their woods in order to inlay them and use them instead of woods of natural color; they use these same dyes to imprint various parts of their productions when they are worked; then these dyes, such as Brazil red, India-wood violet, black, etc., are used hot, which is very easy to do, since it is sufficient that the outside of the woods be dyed. In addition to these dyes, furniture makers sometimes use a species of yellow color for bedsteads, which is compounded of yellow ocher and common varnish, or the same ocher and very light English glue; sometimes they only put water in it, which is worthless.

Before finishing up with the subject of wood dyeing, I thought it would be proper to set forth an inexpensive method for dyeing white woods red; this is done in the following way.

Take horse dung and place it in a tub whose bottom has been pierced with a large number of holes; place this tub over another tub to collect the water from the dung as it decays; and if it does not decay quickly enough, wet it from time to time with horse urine, which assists greatly, and at the same time produces a red water which not only dyes the surface of wood, but penetrates the inside to a depth of three or four lignes. When dyeing woods with this dye, one must take care that they are all of the same species, and roughly of equal density, if one wishes the color throughout be almost even. This observation is a general one applying to all dyes, which are nothing but waters, and do not have any palpable or even apparent thickness; which obliges cabinetmakers to select woods of very similar color and density, as I have said above; this demands great experience and attentiveness on the part of cabinetmakers, to whom - except for the means of compounding the employing dyes - it is scarcely possible to provide theoretical rules regarding this part, whose success is frequently due to experience alone, which is acquired only with a great deal of time, attentiveness and work. [1]