• 1 Pastoureau, 2008; Masters, 2021.
• 2 Travis, 1994, p. 72.
• 3 Travis, 1994, p. 73.
• 4 Fournier, 2014.

1Although black materials have long struggled to find a place in heritage studies, this supposed non-colour has now finally been acknowledged in the history of colour1. Aniline black, the first synthetic black dye, provides a fine example: the advent of synthetic dyes in the 1860s led to the marketing of a wide variety of bright colours which have received far more critical attention until the 1990s2. Yet, this dye had a major position until the 1920s, when 50-60% of the anilines produced in Europe were aniline black and began to decline in the 1930s when it was replaced by new dyes that were easier to apply3. As part of the ERC project Chromotope, the 19th century chromatic turn, an investigation of a collection of synthetic dyes, dated 1918-1970 and constituted at the Conservatoire national des arts et métiers (Cnam), was carried out. The Cnam has been a historical institution devoted to technical education in applied sciences since its foundation in 1794. Now kept at the Musée des Arts et Métiers which belongs to the Cnam, this collection was mainly constituted under the supervision of André Wahl, who held from 1918 the chair of Tinctorial Chemistry at the Conservatoire. This chair was created in 1852 and aimed to teach the various techniques of textile dyeing and printing4. The work carried out for the study of this collection was based on an inventory and archival research, as most of the dyes are poorly documented. This article will focus on the corpus of aniline blacks in this collection, which we will address within the larger history of synthetic blacks from their discovery until the 1930s in order to better shed light on their diverse uses in the many areas of everyday life.

• 5 Holly, 2019, p. 78.
• 6 Runge’s leading role in the discovery of aniline dyes has been questioned by Andreas, 2009, p. 17, (...)

2Aniline black was first observed by the German chemist Friedlieb Ferdinand Runge (1795-1867), who obtained in 1834 an intense dark green material by immersing a cotton fabric previously treated with a dichromate in a bath of aniline salts dissolved in hydrochloric acid5. In this proto-industrial context, his observation had no commercial outlet6.

• 7 Lightfoot, 1871.
• 8 Guignet et al., 1895, p. 64; Rasmussen, 2017, p. 100-101; Rasmussen, 2022.

3After Runge’s first observation, John Lightfoot (1831-1872), an English chemist based in Accrington, north of Manchester, was the first to synthesise aniline black in 1859 while working for Broad Oak Print Works, a company dedicated to calico printing. The Lightfoot process consists on a mixture of hydrochloric acid, aniline, starch and potassium chlorate, applied with a copper roller, which gives an intense dark green colour after 12 hours. Believing that copper played a role in the reaction, he added, in contrast to Runge, copper(II) chloride, a soluble salt7. Aniline black is a polyaniline (Pigment Black 1-C.I. 50440) which had the particularity of not being marketed ready to use: aniline black was formed directly at the dyeing process by oxidation of aniline on the fiber and not beforehand. Thus, this dye could not be sold as such but it was aniline that was purchased. Its structure was only identified in the early 20th century and its several successive oxidative stages are well documented today8: from a fully reduced state, leucoemeraldine, to a fully oxidized one called pernigraniline, the main constituent of aniline black.

• 9 Guignet et al., 1895, p. 645.
• 10 This last point is considered as early as 1859 in a handwritten experiment journal kept in the cent (...)
• 11 Langer, 1990; Holly, 2019, p. 78.

4However, two major drawbacks are reported in the literature: the corrosion of the printing rollers9 and greening of the fabrics10. This was due to a reconversion of partially oxidised and unstable compounds11. This dye was thus suitable for traditional hand printing and with wooden blocks, rather than for industrial techniques based on heavier and faster machines.

• 12 Fauque, 2007.
• 13 Bourel-Bonnet, 2018.
• 14 In 1867, its price was 90 francs per litre (Duchêne, 1867, p. 20).
• 15 Lauth, 1867, p. 6.
• 16 Rasmussen, 2017, p. 104.
• 17 Lauth, 1867, p. 5.

5The issue of accelerated machine ageing in the Lightfoot process was solved by Charles Lauth (1836-1913)12, to whom we owe a great deal of work on colouring materials. Lauth became in 1855 Charles Gerhardt’s assistant, a pharmacist and chemist in Strasbourg13, then Jean-François Persoz’s in 1856, who held the first chair of Dyeing, Printing and Finishing of Textiles at the Cnam. According to Lauth, the colour obtained by the Lightfoot process was bright, strong and affordable14, but not suitable for the requirements of the industry. The improvement he made relied also on the use of a mixture of aniline hydrochloride and potassium chlorate, but adding copper sulphide, which is an insoluble salt unlike copper chloride and acts as an oxidising agent. The advantages of Lauth’s process were celebrated by two medals awarded by the Société industrielle de Mulhouse and by the Société d’Encouragement Industriel15. Lauth developed his process in 186416 and praised its quality to the Members of the jury of the Paris International Exhibition of 186717.

• 18 Anonymous, 1877a; Travis, 1994, p. 75.
• 19 Marie-Anne Sarda (INHA, Paris) is gratefully acknowledged for reporting and transmitting the manusc (...)
• 20 Trademarks registered in the 66th Section (1MA719 and 1MA720, INPI archives).

6Aniline black underwent many variations at a time when every factory was trying to keep the monopoly of exploitation, including the Koechlin brothers, who belonged to one of the major families from Mulhouse involved in the manufacture of indiennes since the mid-18th century, and who were the first to use the Lauth’s process18. Moreover, the importance of aniline black is evidenced in the archives concerning this family, with numerous contemporary recipes for aniline black19. The processes multiplied very quickly after Lauth’s improvement, but beyond the adaptations that may have been developed, the aniline-black craze seems to have been unanimous, as confirmed by the 41 trademarks registered at the Institut national de la propriété industrielle (INPI)20 containing the word “Noir”. These archives illustrate the considerable interest for blacks qualified as “inverdissable”, “inaltérable”, “indestructible” or “indégorgeable”, terms which refer to the drawbacks outlined here above, without mentioning however which synthetic black was precisely used.

• 21 Noelting, 1889, p. 832.
• 22 Murmann, Homburg, 2001, p. 178.
• 23 Fifty-three French patents kept at the INPI have been examined to discuss the importance of aniline (...)
• 24 Lightfoot, 1863, Patent 057192. He filed two other patents in the UK and the USA which he sold to J (...)
• 25 Lauth, 1869, Patent 085554.
• 26 Higgin, 1869, Patent 084185 and Grawitz, 1874, Patent 105130.
• 27 Paraf, 1865, Patent 066816.

7Emilio Noelting (1889), professor at the College of Chemistry in Mulhouse, underlines the great success of aniline black: “The importance of aniline black in dyeing and printing is increasing day by day, and the number of publications and patents to which this dye has given rise has become very considerable21.” Indeed, the invention of the first synthetic dyes brought about a frantic race for patents in Europe and the United States of America (USA)22 in order to secure a monopoly on their manufacture. Their examination has allowed us to better understand the sustainability of its use over time in France23, since the very first patent on aniline black by John Lightfoot in 186324, or Charles Lauth’s in 186925. Apart from the corrosion of printing rollers26 and the greening of fabrics27, two issues already discussed, the preservation of the integrity of the fibres, beyond the fixation of the colour, seems a real concern from the end of the 1870s, as the dyeing bath was systematically done at acidic pH using oxidizing agents, possibly strong, that can damage the textile.

• 28 Guignet, 1889, p. 200.
• 29 Persoz, 1867, Patent 077607; Gouillon, 1868.

8It is admitted that aniline black was used almost exclusively on cotton and according to Charles-Ernest Guignet (1889)28, the range of possibilities was extended to hemp, linen and ramie, but still not applied to wool or silk. This claim can be balanced as more than a dozen French patents, from 1865 to the latest in 1901 specifically mentions processes intended for wool or silk, even if analysis on dresses housed in public collections are lacking in order to verify their industrial development. Jules Persoz, who was Jean-François’s Persoz son and who also taught at the Cnam following his father’s path, patented a process in 1867 on wool dyeing with aniline black which received good reviews in the specialised press29.

• 30 Murmann, Homburg, 2001.
• 31 Sakudo, 2011, p. 24.
• 32 Cussac, 2019.

10After the discovery of the first synthetic dyes, the industrialisation of dye manufacturing became very successful in Europe. France, Germany, the United Kingdom (UK) and Switzerland were the most active countries in this field until World War I (WWI) which is why they feature prominently in the Cnam collection. According to Murmann and Homburg30, the dyeing industry of these countries experienced different stages of development. For the UK and Switzerland, there was minimal fluctuation in output, in contrast to France and Germany, where many companies were created at first (1858-1862). Later, Germany developed its industry in a very dynamic way, unlike France, which, following the controversy over its first dye, fuchsine, saw the number of firms decrease sharply with only a few left in 191431. The German dye industry retained the European monopoly partly thanks to organisational choices. From the 1870s onwards, research and development laboratories were set up in the factories, and marketing and sale were internalised. Germany focused its production on the intermediates as well, which enabled the factories to be partly autonomous32.

• 33 Morris, Travis, 1992.
• 34 This is evidenced by the non-systematic presence of the « Nouvelles Couleurs » section in the Revue (...)
• 35 This chemical dye class is characterized by the presence of two adjacent nitrogen atoms, according (...)
• 36 Hagan, Poulin, 2021, p. 3.

11WWI disturbed the dynamics of the European economic market and this was also the case for the dye industry33. As soon as August 1914, economic relations slowed down and Germany quickly stopped exports to the Allied countries, which led to a shortage of dyeing materials. Switzerland, which stayed neutral in the conflict, took advantage of this situation to develop its own dye industry. During the war, the UK and France partially recovered their dye industry, despite a reorganisation for the war effort34. Various chemical classes of dyes emerged fairly quickly after the discovery of the first dyes, but one of them stood out for the number of products it marketed: azo dyes35. Although less important in terms of the quantity produced, other classes, as anthraquinone, or sulphur dyes after 1905, contributed to the growth of this branch and experienced significant development36.

• 37 Hagan, Poulin, 2021.

12The Cnam collection is composed of 2632 powdered dyes, including 328 blacks, which represents approximately 12.5% of the collection. Among these blacks, aniline black is absent, unlike other early dyes such as mauveine and fuchsine. Among the oldest ones, the museum owns several nigrosines, the first of which was discovered in 1867 by Coupier (fig. 1). The marketing year was collected for several dyes including the latest: CIBA’s neolanes, dated 1926, but also for the most represented class, naphthylamine blacks (15 items), dated 1885. Six chemical dye classes have been identified in the collection, but 33% of the compounds remain chemically unidentified (see table 1). Also, 95% of the chemically identified dyes are undated, as the sources often do not provide very precise information. Nevertheless, according to Hagan and Poulin37, azo dyes are the most represented from the late 1870s to the 1890s and sulphur dyes are attested in 1905, thus, after 1895 which is consistent with the period of development of this later class (fig. 2).

• 38 Tamburini et al., 2021, p. 10.
• 39 Bilbao Zubiri, Carré, 2023.
• 40 Anonymous, 1914a.
• 41 Mauroit, 1910.

13It is worth pointing out that when we refer to black materials, we are not limiting our focus to the production of black textiles or patterns. Some synthetic blacks, giving purple shades on textiles, were reportedly mixed with orange dyes in order to counteract these undesirable shades38, but the few analyses carried out on the museum’s collection could not confirm or refute this statement39. Black dyes were also used to darken other colours, as in the case of immedial black V and immedial brilliant black 5V, which are both sulphur dyes, on hydrone blue40. Moreover, only 34 dyes are named “Grey” in the collection which is not surprising as grey could be obtained from black, as in the use of jet-black diamine CR, an azo dye, in dyeing artificial silk41.

• 42 Rowe, 1924; Dépierre, 1903; Ehrmann, 1922.

14Archival research on these dyes has only made it possible to find the year of discovery or marketing in a large part of the blacks from the collection42, and the Revue Générale des Matières Colorantes has proved to be an essential source that allowed us to cross-reference historical and chemical information on the raw material and the final result by means of sample sheets. In addition, this journal provides valuable information about the provenance and the year of production of each dye, but does not mention when or why production was interrupted.

• 43 Gardner et al., 1999.
• 44 Lefèvre, 1908; Anonymous, 1917, p. 65 specifies inconsistencies on azo dyes referring to anthraquin (...)

15This wide range of marketed compounds led to considerable difficulties in nomenclature from the very beginning, the heterogeneity of which has been reported in the literature43. Most often, the names – chosen by each factory – contain a colour term, and additional information on the hue, the chemical composition, the textile for which it was intended, the technique, or a combination of these elements (i.e. Indanthrene Black B for printing). Names can be a good origin marker, as with sulphur dyes which were named: autogène by the manufacture Société anonyme des matières colorantes et produits chimiques de Saint-Denis (France), katiguène by Bayer (Germany), or pyrogène by CIBA (Switzerland) (fig. 3). The Revue Générale des Matières Colorantes often referred to these terminological problems, which testifies to the confusion that prevailed at the time44.

• 45 Travis, 1994, p. 73.
• 46 Guignet et al., 1895, p. 604.
• 47 Moissan, Dupont, 1902.
• 48 Haute, Leder, 1908; Hayes, 1920; Mac Neil, 1928.

17We have assembled a number of sources that allow us to situate and observe the specific uses of these new synthetic black dyes within the vast market of dye materials. Travis45 already mentions the use of aniline black for objects that require light fastness, without specific mention of a dye class. Synthetic blacks quickly competed with natural dyes traditionally used to dye in black. In 1895, Guignet46 stated that Campeche wood (C.I. 75290) had been almost entirely replaced by azo dyes, both in printing and in dyeing, but also that synthetic blacks were scarcely used on silk, whereas Campeche wood was used with iron mordant and tanning materials. Similarly, Moissan and Dupont47 claimed that synthetic blacks were very successful with cotton flock, and specified that Campeche had been replaced first by azo dyes and then by sulphur dyes (Vidal, immedial, or katiguene blacks). For the ordinary use of inexpensive woollen pieces, direct dyes were used (diamond, alizarin, Victoria, naphthylamine, alizarin on chrome mordant or chromated diamond blacks). Even if the first advantage of these dyes was their low price, the sources cited attest to the continued use of natural dyes imported from afar, which were even less expensive. Furthermore, synthetic black dyes such as nigrosine, but also naphthol, naphthylamine, oxydiamine and alizarin blacks, or a mixture of several of them, were used for dyeing ornamental and functional leathers48.

• 49 Rapp, 1912, p. 229.
• 50 Anonymous, 1914b.

18In spite of the success of second-generation blacks, some sources point to the simultaneous use of synthetic and natural dyes. Rapp49 mentions the use of Campeche wood mixed with synthetic blacks for dyeing woollen dresses, including several dyes present in the Cnam collection: palatine, naphthylamine, chromium anthracene, diamond, acid chromium and palatine chromium blacks (fig. 4). The author states that the dyers adapted their recipes according to the cost, weave and softness or heaviness of the fabric sought, so dyers used synthetic, natural dyes, or mixtures of both. These uses are consistent with the practices mentioned above and reflect the continuity in the use of natural dyes and the diversity of know-how. Furthermore, the reorganization of the colouring industry following WW1 seems to have been combined with a return to natural dyes50.

• 51 Analysing black as a fashionable colour during this period was beyond the scope of this paper. On t (...)
• 52 Mitchell, 2013, p. 613.
• 53 Guignet, 1889, p. 200.

19Black became throughout the 19th century and the first decades of the 20th century the colour of elegance and fashion51, but it is also traditionally the colour of mourning in European societies. For the period that interests us here, it is unavoidable to think of the mourning garments of Queen Victoria (1819-1901), which anchored the ritual codes of mourning since 1861 after the decease of her husband52. In 1895, Guignet stated that “the dyeing of mourning clothing is still a traditional process”, meaning that these garments were dyed with natural dyes. But the use of another black was highlighted by the same author some years earlier mentioning aniline black for printing mourning cloths53. Indeed, mourning indiennes were made of cotton printed with aniline black. Rational choices were made depending on the material and the technique employed, by using synthetic dyes for an accessory and natural dyes for the main garment.

• 54 Among the patents consulted, Patent 094585 is the only one to mention hair dyeing.
• 55 Schueller, 1910, p. 13.
• 56 Ehrmann, 1922, p. 596-597.

20Beside the application of aniline black to mourning attire, aniline black was also used to dye hair, as attested in a few sources. Although a patent54 confirms this use and specifies the toxicity of the dye even in small doses, the magazine La coiffure de Paris, aimed at a female readership, promoted a black aniline hair dye called “oxidant” to recolour oxygenated hair, which could be prepared by the consumers themselves: “They generally consist of two bottles that are mixed together at the time of application55.” It is interesting to note that the qualifying adjective “dangerous” accompanies the explanation of the dyeing process, which underlines once again its toxic aspect. Nevertheless, the quality of this black is emphasised, describing the result as “even too beautiful”, as its quality surpassed that of natural dyes. Ehrmann56 also mentions the use of aniline black for hair dyeing, without giving any further details.

• 57 Pierrot, 2018.

21Several European firms simultaneously developed and diversified their activities in promising industrial branches. Among these sectors, a clear link can be made between the dye and the pharmaceutical industries, but also with the photographic industry, which experienced the boom of photographic printing in the 1880s and a revolution with the appearance of the cinematograph in 189857. The best example of this is the Berliner factory Actiengesselschaft für Anilin Fabrikation (AGFA), which was founded in 1867 and initially produced dyes, before being progressively redirected to the photographic industry.

• 58 Lemaire, 1911, p. 23.

22At the beginning of the 20th century, Louis Lemaire58, a chemical engineer and general secretary of the Union Photographique, a workers’ association (1893-1920), published on the use of aniline dyes for diapositives tinting. Lemaire cites some azo dyes recommended for colouring gelatin-coated glass plates, that are “found in all dyeing laboratories” and chosen according to their affinity with the support and their light fastness. To obtain a blue-black, amine blacks 4B, 10B, 54B and feather black were recommended, for a violet-black, naphthol black was suggested, and finally, for a purple-black, naphthylamine black was advocated. Among these, only naphthols from the Manufacture lyonnaise des matières colorantes are present in the Cnam collection. The author also mentions the possibility of mixing amine black 4B, paper yellow and lanafuchsine 6B, to get a blue-black. According to Lemaire, these colours were best applied with a soft brush rather than by immersing the plate in a bath. These sources testify to the broadening of the uses of dyes, as well as to the manual application of these colours, contrary to the textile dye industry which had undergone significant mechanisation since the 19th century.