4 LITERATURE SURVEY

Before beginning the colorant analysis, it was necessary to conduct a review of the literature to help guide the identification process. A considerable amount of information exists on pre- and postconquest New Spanish colorants, but the information is widely scattered throughout disparate fields of study. While this article compiles, as much as possible, existing information into one source, it is by no means complete.

4.1 SOURCES

Two 16th-century sources were useful in researching Mexican colorants. The most complete work with descriptions of Native colorants in the Historia General de las Cosas de Nueva Espa�a, also known as the Florentine Codex. It is a three-volume encyclopedia of 12 books produced by Fray Bernardino de Sahag�n in Tlatelolco, 1575–80. The Florentine Codex documents many colorants used by Aztec scribes, including names and descriptions, in the Aztec language, Nahuatl, and in Spanish. Dibble and Anderson translated the Nahuatl descriptions in the Florentine Codex into English during the years 1950–82. The second useful source for 16th-century New Spanish colorants is the Badianus Manuscript, also known as the Libellus de Medicinalibus Indorum Herbis and the Codex Barberini. This work was produced by two Aztec scribes in 1552 at the Colegio de Santa Cruz in Tlatelolco. Emmart translated the work into English in 1940.

Both the Florentine Codex and the Badianus Manuscript provide the Native names of 16th-century New Spanish colorants in Nahuatl. More than 100 Native languages were spoken in Mesoamerica when the Spanish arrived in the 16th century, but Nahuatl is the best known for several reasons (Gruzinski 1992). By the 16th century, Nahuatl was the universal language of Mesoamerica. It was an “established language of commerce, of political administration, a lingua franca for an enormous expanse of territory” (Harvey 1972, 299). Because of the work of Fray Sahag�n and other Christian clerics, many works were produced for the purpose of translating Nahuatl into Spanish (Williams 1990). This article provides the indigenous names of colorants in Nahuatl unless otherwise specified.

In addition to 16th-century sources, I also consulted contemporary sources on Mexican pigments, plants, and minerals. Those particularly useful include works by such authors as Emmart (1961), Donkin (1974, 1977), Panczner (1987), Standley (1967), Torres (1988), and Wallert (1995, 1997). Sylvia Rodgers Albro, senior paper conservator at the Library of Congress, generously lent her time and expertise from her studies of pigments on two 16th-century New Spanish manuscripts: the 1531 Huejotzingo Codex (Albro and Albro 1990) and the Oztoticpac Lands Map.

4.2 COLORANT TABLES

Tables of some, but not all, 16th-century New Spanish colorants are included in the appendix. The tables give the color; the English name of the colorant; the Native and/or Spanish name; the botanical, zoological, or mineral source; the geographic region where the colorant was obtained; and the permanence and stability.

From the literature that I reviewed, I failed to find significant information on six inorganic colorants identified in the samples from the RGs. These colorants (cinnabar, red lead, azurite, green earth, raw umber, and burnt umber) are excluded from the literature survey but included in the tables.

4.3 ORGANIC COLORANTS

4.3.1 Red

Annatto (Bixa orellana) is a red, light red, or yellow dye made from the dried seeds of an evergreen shrub that grows in Mexico and Central and South America (Donkin 1974; 1977). The Aztecs called the red dyestuff achiotl, and the Spanish referred to it as achiote(Emmart 1940; 1961). Annatto was used as a dye for fabrics, cosmetics, and food and as a painting medium (Krochmal and Krochmal 1974). Donkin (1977) indicates that along with cochineal, annatto was a reddish brown colorant commonly used for Mexican manuscript painting in the 16th century and before. It is still used as a dye component in cosmetics and foods. As with most organic colorants, annatto fades with exposure to light (Donkin 1974). It is insoluble in neutral water but soluble in mild alkali solutions (Wallert 1997).

Cochineal (Coccus cacti, Dactylopius coccus) is a carmine red dyestuff made from the dried bodies of female insects. These insects are Native to Mexico and North, Central, and South America (Schweppe and Roosen-Runge 1986) and are parasites of cacti belonging to the genera Opuntia and Nopalea (Donkin 1977). The Aztecs called the carmine red colorant nocheztli; the Spanish referred to it as grana cochinilla or cochinilla. Cochineal was employed in a variety of uses: as a paint for manuscripts and decorative objects, as a dye for fabrics and textiles, as a coloring agent for consmetics, and as a medicine. Today it is used as a coloring agent for medicines, foods, and cosmetics (Donkin 1977; Schweppe and Roosen-Runge 1986). Cochineal is susceptible to fading and color changes with prolonged exposure to light. In addition, it will change color when exposed to acids and alkalis (Schweppe and Roosen-Runge 1986).

In pre-Columbian times, cochineal was cultivated for local use and trade in western and south-central Mexico (Donkin 1977). Krochmal and Krochmal (1974, 17) indicate that “the Aztec leader, Montezuma, received some of his taxes in the form of cochineal.” The Spanish discovered the brilliant red dyestuff not long after their arrival in Mexico in 1519, and “it is possible that samples of cochineal were among the first Mexican products to be shipped to Europe” (Donkin 1977, 23). Donkin suggests that cochineal became the third most valuable export product after gold and silver. Until the late 18th century, it was mainly cultivated in central and southern Mexico and parts of Central America, especially Guatemala and Honduras. By the mid-19th century, the cultivation of cochineal spread to Peru, India, Java, and the Canary Islands (Donkin 1977).

Logwood (Haematoxylum campechianum) is a red dye made from the heartwood of a tree that grows in Mexico, Central America, and northern South America (Emmart 1961; Krochmal and Krochmal 1974; Donkin 1977). Standley (1967) indicates that the Haematoxylum brasiletto tree is often confused with the Haematoxylum campechianum tree, and in the area of commerce there is no distinction between the two. The use of dyestuffs from the two trees is identical. Depending on the alkalinity or acidity of the logwood dyestuff preparation, the resulting colors include red, reddish purple, purple, blue, or black. The Aztecs called the tree from which the logwood dyestuff was extracted quamochitl, huitzeuahuitl, and uitzquauitl, while the Spanish referred to it as brasil(Emmart 1961). The term brasil should not be mistaken for the dye brazilwood. Harley (1982, 144) states that “the word brasil originally meant red, from the same root as the Latin rosa.” The logwood dyestuff was used for manufacturing writing inks and watercolors and for dyeing fabrics and textiles (Gettens and Stout 1966; Krochmal and Krochmal 1974). As with cochineal and indigo, it was an important New World product that was exported to Europe. It is still used for dyeing fabrics (Ponting 1973). Logwood dye is fugitive to light; it is insoluble in water and alcohol but changes color with exposure to acids (blood red) and alkalis (bluish violet) (Gettens and Stout 1966).

Emmart (1940; 1961) states that a scarlet red dye was made from the red leaves of the poinsettia plant (Euphorbia pulcherima), which grows in Mexico and Central America. Standley (1967) indicates that while the dye was obtained from the leaves, the bark contains the red coloring agent. The Aztecs called the plant cuetlaxochitl.

4.3.2 Purple

Tyrian purple (Purpura patula, P. pansa, Mexico and Central America; Thais kiosquiformis, South America) is a red, violet, or deep purple dye made from the fluid secreted from specific mollusks that live in the waters off the west coast of Mexico, Central America, and northwestern South America (Donkin 1977; Wallert 1997). The hues vary depending on the species of mollusk and the extraction process (Gettens and Stout 1966). Wallert (1997, 61–62) indicates that glandular extractions from these mollusks “are at first yellowish but when exposed to air and sunlight change from green to blue and then to reddish purple.” Tyrian purple was used for dyeing textiles and fabrics and as a paint for manuscripts (Donkin 1977). Gettens and Stout (1966, 162–63) indicate that “the purple color is remarkably stable, resisting alkalis, soap, and most acids.”

Wallert mentions another indigenous purple colorant made from the shrub Jatropha curcas, which is commonly found in tropical areas of the Americas. From Wallert's description, it seems that the colorant was obtained from the seeds of the plant and was called cuauhy-ohuachtli by the Aztecs (Wallert 1997). Standley (1967) indicates that it was used as dye and a paint.

4.3.3 Yellow

Two organic yellows are mentioned in Sahag�n's Florentine Codex and are analyzed by Wallert (1995, 1997). Their Aztec names are �acatlaxcalli or zacatlaxcalli, and xochipalli(Sahag�n 1963, book 11). No Spanish or common name is given.

Zacatlaxcalli ranges from light to bright yellow in hue. The colorant is obtained from the plant stems of various dodder species (Cuscuta tinctoria, C. americana, C. odontolepis; Cassytha filiformis) that grow in Mexico and North and Central America (Wallert 1995, 1997). Wallert (1995, 658; 1997, 63) emphasizes that “the plant's taxonomy does not always seem to be clear, and there is some confusion in the literature concerning the differentiation in the Cuscuta and Cassytha species.” He implies that different yellow hues result from various ages of the plants. “The younger stems appear greenish yellow, the older stems are an orangy yellow, and the oldest stems have a bright and strong orange colour. These differences in colour correspond with differences in composition during the life cycle of the plant” (Wallert 1995, 658; 1997, 64).

Xochipalli ranges in hue from yellow to orange-yellow. The colorant is derived from the petals of a flowering plant (Cosmos sulphureus) that grows in Mexico (Wallert 1995; 1997).

Both yellow colorants were used as painting mediums and dyes for fabrics, but xochipalli was used for medicinal purposes as well (Sahag�n 1963, book 11; Wallert 1995; 1997). Cordry and Cordry (1968, 6) state that the mustard yellow colorant zacatlaxcalli “was used in Mitla, Oaxaca, until about 1940.”

4.3.4 Blue

Several blue colorants were manufactured from Native Mexican plants. Indigo is a blue made from the leaves of theIndigofera suffruticosa plant that grows in Mexico and Central and South America (Torres 1988). The Aztecs called the blue colorant xuiquilitl, whereas the Spanish referred to it as azul de a�il, or simply a�il. Indigo was used as a dye for fabrics and textiles, and as a cosmetic by the Aztecs (Emmart 1940; 1961). It is possible that the Aztec dark blue colorant tlaceuilli is the same as xuiquilitl. In their translation of the Florentine Codex, Anderson and Dibble suggest that tlaceuilli was made “from the leaves of the xuihquilitl pitzauac (Indigofera a�il)” (Sahag�n 1963, book 11, 242). Indigofera a�il is the Old World species of indigo (Emmart 1940; 1961). The Florentine Codex indicates that tlaceuilli was made from the juice of the macerated leaves of an herb that Wallert (1995) has identified as I. suffruticosa, the New World species of indigo. Tlaceuilli was used as a painting medium and a dye (Sahag�n 1963, book 11). Indigo also became a valuable New World export product and is still used as a dye for fabrics. Schweppe (1997) offers many other plant species that were used for the production of indigo in the New World.

Gettens and Stout (1966) indicate that thin films of indigo can fade with exposure to strong light. Schweppe (1997), on the other hand, states that its lightfastnes is good as a pigment ground with a substrate. He describes the effect of atmospheric compositions on indigo as stable with exposure to hydrogen sulfide, as less reactive with exposure to ozone in the absence of light and to nitrogen dioxide, and less reactive to traces of nitric acid. Indigo is insoluble in water, dilute alkali solutions, acids, alcohol, and ether (Gettens and Stout 1966; Schweppe 1997).

Another blue colorant, texotli, is described as varying in hue from light blue, to blue, to green (Sahag�n 1963, book 11). Texotli was made from the leaves or flowers of the matlalin plant whose taxonomy is unclear. Anderson (1948) suggests that the plant is Indigofera suffruticosa, in which case the blue colorant is derived from the leaves. Torres (1988) indicates that the plant is Commelina celestis, from which a blue is derived from the flowers. The texotli colorant, Torres says, was manufactured in western Mexico in the state of Michoacan. The exact uses of texotli are unclear.

A final organic blue colorant is identified in the Florentine Codex as matlali(Sahag�n 1963, book 11). Anderson (1948) describes matlali as a dark green or blue-green colorant made from the flowers of the matlalquauitl plant (Guaiacum coulteri). This blue colorant was used as a painting medium.

Both Emmart (1940; 1961) and Wallert (1995; 1997) mention mohuitli, a blue colorant made from plants of the Jacobinia species: J. mohintli (also known as J. tinctoria) and J. umbrosa. plant is currently known as Justicia spicigera. The plant grew in abundance in Oaxtepec, Mexico. Standley (1967) indicates that the blue colorant is derived from the leaves of the plants and was used as a dye.

4.3.5 Brown

An organic brown colorant is identified in the Florentine Codex as quappachtli. It is derived from ground-up Spanish moss (Sahag�n 1963, book 11), possibly from the Tillandsia usneoides tree. The dyestuff varies in hue from dark yellow, to dark brown, to violet (Anderson 1948).

4.3.6 Black

Charcoal black is made from “the dry distillation of woods” (Gettens and Stout 1966, 104). Native Mexican scribes made a black colorant from the soot of a resinous pine tree that Anderson (1948) speculates is Pinus teocote. The Aztecs called this black colorant tlilli and tlillocutl(Anderson 1948; Sahag�n 1963, book 11). It was a used as a dye, a paint, and an ink (Sahag�n 1963, book 11). Charcoal black remains stable when exposed to light, air, and hot concentrated acids and alkalis (Gettens and Stout 1966).

Nacazcolotl was used as a black paint, an ink, and a dye (Sahag�n 1963, book 11). Anderson (1948, 23–24) identified it as “gallnut,” made from the “pods of the Caesalpinia coriaria.” The color varies in hue from black to dark green. In addition to its use as a paint and an ink, it was also used as a dye (Sahag�n 1963, book 11). Standley (1967) indicates that Mexican scribes made black ink from the pods of the C. coriaria before the Spanish conquest. It is likely that nacazcolotl was similar to the European iron gall ink. Iron gall ink deteriorates paper and fades with exposure to extreme environment conditions and high pH aqueous deacidification methods (Ash 1994).

4.4 INORGANIC COLORANTS

4.4.1 Red

Tlavitl was a red colorant manufactured from the mineral red ochre (Sahag�n 1963, book 11). Anderson (1948) indicates that the red colorant was used as a paint. Red ochre is an iron oxide red colored by anhydrous ferric oxide (Fe2O3). Gettens and Stout (1966) indicate that red ochre is stable and unaffected by light and dilute acids and alkalis, but it can darken with exposure to heat.

4.4.2 Yellow

In the Florentine Codex, a yellow colorant is described as being made from the grinding of a yellow stone (Sahag�n 1963, book 11). Anderson (1948) states that the Aztec colorant teco�auitl is yellow ochre. It was used for painting and writing. Yellow ochre is colored by various forms of hydrated iron oxide, especially goethite [FeO(OH)]. It is unaffected by light and dilute acids and alkalis (Gettens and Stout 1966).

4.4.3 White

Of four inorganic white pigments mentioned in the Florentine Codex, only one appears to be known. Calcite, called teti�atl by the Aztecs, was made from ground, heated limestone (Anderson 1948; Sahag�n 1963, book 11). Calcite is the most common form of calcium carbonate (CaCO3). Calcium carbonates are stable when exposed to light but deteriorate with exposure to atmospheric acids. In addition, calcium carbonate whites can discolor alkali-sensitive colors (Gettens, Fitzhugh, and Feller 1993).

4.5 MIXED COLORANTS

4.5.1 Blue

Maya blue is a bright blue, slightly green colorant that was manufactured in Mexico and Central America. It is a synthetic and a complex of an inorganic clay and an organic blue colorant. Most sources indicate that Maya blue is made from palygorskite, a white clay, that is dyed with indigo and heated. Some sources refer to the white clay base as attapulgite, a type of palygorskite (Gettens 1962; Arnold and Bohor 1975). Additional examination of Maya blue reveals the presence of other white clays, including sepiolite and montmorillonite. Maya blue is a stable colorant that “is resistant to diluted mineral acids, alkalis, solvents, oxidants, reducing agents, moderate heat, and even biocorrosion” (Jos�-Yacam�;n et al. 1996, 223).

Maya blue was used as a paint for murals, ceramic objects, and illuminated manuscripts. Arnold and Bohor (1975) state that in pre-Columbian times Maya blue was used exclusively for ceremonial purposes. They further indicate that the colorant was assoicated with sacrific: “The human sacrifical victims and the stone altars on which they were laid were painted blue before their beating hearts were removed” (25). Use of Maya blue extended from pre-Columbian times to the 20th century in Mexico and the 19th century in Cuba (Tagle et al. 1990; Jos�-Yacam�n et al. 1996).

Until recently Seri blue was commonly used by the Seri Indians of Sonora in northwestern Mexico. They call this pigment antezj k�il. Like Maya blue, Seri blue is a clay-organic complex. The blue colorant results from the mixture of an off-white montmorillonitic clay and a green organic resin from the plant Guaiacum coulteri with water (Moser 1964; Peirce 1964). Peirce (1964) indicates that Guaiacum coulteri grows as far south as Oaxaca and that Guaiacum sanctum, a similar species, grows in Yucat�n. Peirce likens Seri blue to Maya blue and contemplates whether the two are somehow connected. While there might be a correlation between Seri blue and Maya blue, it is uncertain whether Seri blue was used outside of northwestern Mexico. However, Anderson (1948) suggests that the Aztecs also made a dark green or blue-green colorant, matlali, from the flowers of G. coulteri. Although neither Sahag�n nor Anderson mention that matlali was made with a clay base like Seri blue, it is possible that the two colorants are similar.

Gettens (1962) states that Maya blue is stable in concentrated nitric acid, but Peirce (1964) indicates that Seri blue is not. Moser (1964) states that the Seri Indians used the blue colorant for “decorating pottery, clay figurines, headdresses, fetishes, arrows, wrist guards, and cane gaming sticks, as well as for face painting” (31).

4.5.2 Green

The Florentine Codex describes two green colorants: iiappalli (dark green) and quiltic (green or dark yellow) (Anderson 1948; Sahag�n 1963, book 11). Both greens are mixtures of blue and yellow colorants. Anderson (1948) says that iiappalli was made by mixing the leaves of an unidentified plant with a mixture of the blue texotli (matlalin) and the yellow zacatlaxcalli (various dodder species). Similarly, he indicates that quiltic was a mixture of texotli and zacatlaxcalli. The green colorants iiappalli and quiltic were most likely used as paints (Sahag�n 1963, book 11).

4.5.3 Brown

Camopalli was a brown colorant obtained from the mixture of cochineal and alum. It was used as a painting medium and a dye (Sahag�n 1963, book 11).

4.6 BINDERS

In the literature surveyed, three sources mentioned pigment binders in use in pre- and postconquest New Spain. Emmart (1940, 34) indicates that the Aztecs mixed pigments with an oil from the insect Coccus axin called “axi, axin or aje.” Standley (1967) states that the Coccus axin insect lives in the branches of the Jatropha curcas and Spondias mombin trees. In addition, he provides descriptions of axi, axin, and aje (Standley 1967). Albro and Albro (1990, 105) refer to the binder “tzacuhtli, a natural adhesive similar to gum arabic or cherry gum, obtained from the roots of an orchid plant (Epidendrum pastoris).”