maya blue recipe

After discussing Indigo as Pigment, I’ve had a lot of requests to share the process for making Maya blue. This recipe is based on the research of Michel Garcia, whose Natural Dye Workshop DVD series I recommend. To make Maya blue pigment at home, only two ingredients and a few tools are required.

  • Botanical indigo powder: This can be store-bought or home processed, and must be thoroughly dry and finely ground.

  • Clay substrate: Sepiolite, palygorskite or attapulgite will absorb the indigo when heated. You can purchase small jars here, or larger amounts here. If your clay is granulated of foraged it must be finely ground.

  • Mortar and pestle for grinding: This must be dedicated to crafts only, never food.

  • Dust mask: These types of clay can be irritating.

  • Small pot: Likewise dedicated to crafting.

  • Mulling slab and muller: For extra finely grinding the finished pigment and mixing paint.

 grinding sepiolite clay

grinding sepiolite clay

Make certain that none of your tools have any water on them, as even a drop will spoil the reaction. After finely grinding, weigh 10 parts clay and 1 part indigo powder. I have used 30 grams sepiolite and 3 grams indigo. Combine these in a small pot and heat over a medium low flame.

Over the course of a few minutes, you will see the two powders combine and turn a uniform blue color. At 356 degrees Fahrenheit the indigo sublimates to a gas, bypassing the liquid phase, and is immediately absorbed by the clay. Remove the pot from heat and allow to cool. The color will have a violet tinge when hot, but turn turquoise as is cools. You now have Maya blue pigment, indigo locked inside and stabilized by the clay.

maya blue recipe
  • A Weighed indigo and sepiolite

  • B Mixed indigo and sepiolite before heating

  • C Mixture after heating: Maya blue!

Maya blue pigment may be stored indefinitely. To use as paint it must be finely ground with a mortar and pestle followed by mulling with a binder to mix the paint of your choice. Check out Kremer Pigments and Kama Pigments course offerings and videos to learn how to prepare your own watercolor, egg tempera, or oil paints.

 mulling maya blue watercolor

mulling maya blue watercolor

indigo as pigment

Straying a bit further afield from the recent posts on alum and the quantity of alum used in paper marbling, let's address the question obliquely raised in the last post on lake pigments:

Indigo is a pigment?

Many of us natural dyers are well familiar with the process of concocting an indigo vat and the working properties of indigo as a dye. It is truly remarkable that so many historical cultures throughout the world developed a practical understanding of the complex chemistry governing the indigo vat, leaving us with a wealth of cultural and artistic heritage centered on this beautiful dye. But indigotin, the indigo blue which colors fibers dyed in the indigo vat, is an insoluble organic compound and can be used as a pigment. It may be mixed with a binder for use as paint without going through the trouble of making an indigo vat. Let's review the process by which indigo is made:

  • Indigo precursors naturally occur in the leaves of an indigo-bearing plant. After harvesting, these precursors are converted by enzymatic hydrolysis to indoxyl.

  • When oxidized, two indoxyl molecules join with oxygen to form indigotin.

  • Indigotin is indigo blue! Indigotin is insoluble, and can be used as a rich navy blue pigment.

  • Natural dyers now mix up their indigo vats to reverse the process. To work as a dye, an antioxidant reduces indigotin to leuco-indigo suspended in water. Fibers lowered into the vat become saturated with leuco-indigo, which spontaneously oxidizes to indigotin when lifted from the vat and exposed to air.

It's quite the feat of organic chemistry, but the peculiar dual nature of indigo provides its distinction as an artists' material. Used as a dye, indigo's working qualities have inspired resist techniques in cultures around the world. After dyeing, the indigo is not chemically bound to fabric and can be abraded from it with much washing and wearing, giving us the particular worn-in look of denim. And because indigo is inert when oxidized, it has better lightfastness that other natural dyes.

grinding indigo pigment
mulling indigo pigment

Sources of indigo pigment

In medieval Europe, indigo was prepared as a pigment by skimming and drying the flower from the surface of a woad vat, called blue florie, or grinding white lead with imported indigo. Indigo was widely available, fairly inexpensive, and in common use as a workaday blue pigment. It is a strongly tinting, dark, and slightly greenish shade of blue. Indigo is certainly a regal dye, one of the few lightfast historical grand teints. But as a pigment, its lightfastness did not match the more permanent and expensive mineral blues.

For use as a pigment today, pure indigo can be finely ground and mixed as watercolor, tempera, or oil paint. If you're a dyer, you can use the botanical indigo powder you already have on hand. You can also purchase the genuine botanical pigment from Kremer,* from Cornellisen in the UK, or you can buy Genuine Indigo paint pre-made by a reputable paint manufacturer.

Synthetic indigo was formulated in the late nineteenth century and is chemically identical to indigotin. Slight color variations between synthetic and botanical indigo are due to additional organic compounds extracted from different species of indigo bearing plants, including the colorant indirubin, which influence the shade of blue. Either botanical or synthetic indigo can be used as a pigment, but not indigo dye sold 'pre-reduced.'

*or get sidelined by Tyrian purple, the other famous vat dye with similar chemistry

 homemade indigo and maya blue watercolors

homemade indigo and maya blue watercolors

What is Maya blue?

Maya blue is an indigo derived pigment used by ancient Mayan and Aztec artisans to color murals and ceramics. This pre-Columbian azure colored pigment is so stable and lightfast it was long thought to have a mineral origin. It is made by heating a finely ground dry mixture of indigotin and clay, either palygorskite, attapulgite, or sepiolite, to 356 degrees Fahrenheit. At this temperature the indigo is sublimated as a gas and replaces water in the clay, becoming a stable compound. Once cooled, Maya blue pigment can be mixed with a binder and used in all sorts of applications. Given that Maya blue requires a small amount of indigo, is lightfast, and is a lovely turquoise shade, it is superior to pure botanical indigo as a pigment.

I have only found Maya blue pigment available from Rublev, but it is not a difficult pigment to make at home. I have small jars of sepiolite clay available in my shop, as it can be difficult to source.

How do indigo and Maya blue fare in paper marbling?

Below are the results of some preliminary marbling experiments with homemade indigo watercolor and Maya blue watercolor.

  • Top: indigo watercolor

  • Middle: Maya blue watercolor

  • Bottom: both shades of blue

  • Column A: no mordant

  • Column B: pre-mordanted with 1.5 teaspoons aluminum sulfate/pint water

marbling tests with indigo pigments

I did struggle with getting the Maya blue to behave, though it functioned well in previous trials alone and mixed with lake pigments. The indigo blue has a beautiful rich hue, and will be useful for mixing dark shades.

As you can see in the right column, the pre-mordanted paper takes a crisper print with less streaking. The question of mordanting for indigo pigments was raised in the wonderful book Marbled Paper: Its History, Techniques, and Patterns:

Why, it may be asked, can some colors (such as indigo) derived from non-metallic materials, seemingly be employed without the use of a mordant? The answer can only be advanced in stages. To begin with, indigo, like the lake colors, which it resembles in several ways, has a low specific gravity. Secondly, it is likely that in its earlier, unsynthesized state, indigo contained minerals and metallic traces. There is good reason to suspect that somewhere during its manufacturing process or final preparation, alum was added, because earths, presumably containing alum and mineral salts, such as chalk, were often added as extenders to cut costs. But, most of all, indigo (like a few other dye-bearing plants) was insoluble in water, and had the ability to fix itself to an organic fiber without the aid of a mordant.
— Richard J. Wolfe

We know that historical paint manufacturers (and maybe some today) stretched or lightened indigo with the addition of various earths, inadvertently making a paint useful for marbling without a mordant. My homemade indigo paint is concocted of pure botanical indigo powder, which apparently does not have enough trace minerals to work quite so well without the help of a mordant.

However, Maya blue is useful for marbling without a mordant due to the chalk in its formulation. It is a lovely (though faint in this test), stable color which European marblers never had access to until the recipe was reverse-engineered in recent years.

Update: After 1 month of exposure to direct sunlight, no fading has been observed in either indigo or Maya blue watercolor samples on unmordanted paper. Lightfastness concerns about indigo pigment can be reserved for very long term light exposure.

on alum

I’ve recently undertaken a series of tests, as scientific as I can make them, to answer some questions I commonly receive from students and satisfy my own curiosity.

Firstly:  What is the difference between the various types of alum?

If you have done any natural dyeing or marbling, you have most likely used alum as a mordant. Alum is a metallic salt which bonds to both the fiber substrate and the coloring agent, creating an insoluble bridge linking them together.  Whether you are using dyes or paints on fabric or paper, an alum mordant will increase the amount of color that can latch on, and improve the washfastness and lightfastness of the finished piece. Alum is the most commonly used mordant because it is inexpensive, colorless, permanent, and toxic only in large doses.

I, like many marblers and dyers, am in the habit of using the term ‘alum’ to refer to two different compounds: potassium aluminum sulfate and aluminum sulfate. These two metallic salts function essentially the same way for mordanting, but it's worthwhile to consider their differences. I will not include aluminum acetate in this discussion, as it is always specified by name and is not in common use for marbling paper.

marbling tools.jpg

Potassium Aluminum Sulfate
Historically called potash alum, potassium aluminum sulfate is a translucent white crystalline powder.  It is naturally occurring, and has been extracted from alunite in volcanic areas since at least 1500 BC for purifying water, as a styptic, and a mordant. Today it can be refined from bauxite or alunite, or made in a laboratory by adding potassium sulfate to aluminum sulfate. Potash alum is the historical mordant called for in traditional dye and marbling instructions, and in making lake pigments from natural dyes.

Aluminum Sulfate
Aluminum sulfate can be made in a laboratory or refined from various types of stone. In appearance its crystals are jagged, with an opaque white dustiness. Since its introduction as an industrial product in the 19th century, it has replaced potash alum in many applications such as water purification and paper sizing, and is sometimes called papermaker's alum.

What's the difference?

  • Potash alum and aluminum sulfate may be used interchangeably as a mordant on both cellulose and protein fibers.
  • Potash alum is slightly more expensive.
  • Some dyers claim that potash alum gives clearer colors, but I have not noticed any difference between the two. If you have trouble with muddy colors, make sure your alum is from a reputable vendor. Any impurities, such as iron, will sadden your colors.
  • If you are forging historical artwork, using aluminum sulfate to mordant is a dead giveaway.
  • Both potash alum and aluminum sulfate are acidic. Whichever you use, follow mordanting instructions to avoid making your artwork overly acidic and brittle.
  • Most important for practical purposes: Aluminum sulfate is more water-soluble at room temperature. When mordanting paper, most historic manuals call for heating the water before adding potash alum (they don’t specify which alum, but potash alum is implied). Heating the water will allow the potash alum to dissolve quickly.
alum solubility chart

I made this chart from what scant data I could find, showing the solubility of both sorts of alum in one pint of water. Paper marblers generally use between 1-4 tablespoons of alum per pint, or about .5-2 ounces. Though both potash alum and aluminum sulfate are soluble at room temperature in that amount, in my experience warm tap water helps to speed up the dissolution of the crystals.

Please be in touch if you have any information to contribute, or reading to recommend! The alums and their history are a big topic.

fermentation dyeing

Yes, I know it's midsummer and I haven't written a thing about what I've been dyeing. My latest dyeing mania is a somewhat lengthier process than usual - but it's Amazing. Fermentation Dyeing.

There is not as much information as I'd wish about plant fermentation dyeing, but from what I gather the method was salvaged from history by Anne Rieger in the south of France. The process begins by fermenting plant matter in water for a week or more, releasing the gas and stirring the contents daily. After straining, the dye is separated into two vats. Lemon juice is used to lower the pH of one vat to 4, while wood ash water raises the pH of the other to 11. Protein fibers are steeped in the acidic bath, dried out of the sun, and then submerged in the basic bath. And just like that, you have lightfast color with no heat and no mordants. The colors are beautiful, and the wool  samples I've dyed have the most wonderfully soft hand. Cellulose fibers also seem to take the color when given a longer steeping period, but not as strongly. Some inspiration can be found at Riihivilla and Shades of Lynx, and check out the samples I've been working up below.

above, from left:  basic dahlia, acidic dahlia; basic cherry leaf, acidic cherry leaf

above, clockwise from upper left: acidic elderberry, acidic dahlia, basic dahlia, basic elderberry

cherry leaf and twig