Introduction
Before the time of photography it was the coloured drawings made by skillful artists and craftsmen that gave us an impression of the morphology and coloration of things and lifeforms. In the past there have been some articles in the Journal covering certain bromeliads in publications illustrated by such coloured plates. For instance, there was the series "Icones Bromeliacearum" by Robert Read. And some of the drawings that Édouard Morren collected and are now in possession of the Kew Library were presented to us by Lyman Smith. This all was about 20 years ago and much remains hidden in the archives, although more and more can now be found on the internet (the Missouri Botanical Garden is doing a particularly good job with their digital library of botanical literature). My own investigations in this field were principally aimed at the horticultural magazines of the 19th century but were expanded to works that followed the same way of presentation, like albums. Much information about those I gathered from the standard works on taxonomic literature (Stafleu and Cowan 1976). At the end of the 18th and start of the 19th century Europe saw the rise of many horticultural magazines that would become best known for their colourful illustrations of plants. It was the time of exploration and the plant-hunters found many exotic new species, including spectacular bromeliads. In general the magazines in England, France, Belgium and Germany followed the same concept in publishing the plants: a colourplate on one page, sometimes as a foldaway, and one or more pages with text giving a description and information on habitat and culture. Although the texts present very interesting reading the main attraction is formed by the plates: therefore some explanation on how they were made is in place. In the period concerned, two methods are of interest. The first and oldest one is engraving: in a metal plate - mostly copper, also steel - lines were engraved with a sharp metal tool. This could also be achieved with an acid, here a drawing was made first on the wax-covered metal, this etching was often combined with engraving. From the engraved metal plate, prints on paper could be made by filling the lines with ink, ensuring the surface of the plate was wiped clean. The other technique is lithography, discovered in 1798 in Germany by Aloys Senefelder. It is based on the fact that water and fat repel each other and achieved by making a drawing on a slab of stone with a greasy substance, after which the stone is wetted with water. The water is rejected by the lines of the drawing and when ink is applied, this only sticks to the greasy drawing, not to the wet surface. Like a metal plate, the stone can be used to make many prints. After 1820 publishers tended to use lithography for the plates in books and magazines and especially Belgian lithographers reached the ultimate of craftmanship in a relatively short period of time. In later times, instead of stone, also zinc and aluminium were used. Both techniques produce a print on paper in black and white; colour was applied by the artist by hand, mostly using watercolour paint. From 1830 onwards colourprints appeared, made through a process of repeated printing with several printforms and with different colours of ink. The process was made more easy by offset printing, using a roller covered with rubber as an intermediate step, also having the advantage of avoiding a mirror image on paper.
Literature cited:
Stafleu, F.A. and Cowan, R.S. (1976-1988). Taxonomic literature vol.1-7, Ed.2. Bohn, Scheltema and Holkema. Utrecht, The Netherlands.
Oil painting from 1860 by François-Auguste Biard, titled 'Amazonian Indians worshiping the Sun God' (Pinacoteca do Estado de São Paulo)