The first invention which we shall notice is that which is known by the name of Nature-printing, and which has been so successful in transferring to paper an exact representation of vegetable foliage.
One simple tolerably efficacious mode of Nature-printing has long been known. A piece of paper being rubbed with lamp-black and oil, the leaf was laid upon it and gently rubbed, so as to transfer the lamp-black to the nervures. It was then laid on a sheet of white paper, and again rubbed, when an impression of the leaf was left upon the paper.
The present system of Nature-printing is far in advance of this rather rude method, and amounts to an exact reproduction of the plant, not only in form and detail, but in colour.
In order to illustrate this beautiful process, I cannot do better than transfer to these pages the following account of Nature-printing as given in Ure’s “Dictionary of Arts,” &c. It is an abstract of a lecture delivered by Mr. H. Bradbury at the Royal Institution.
“Nature-printing is the name given to a technical process for obtaining printed reproductions of plants and other objects upon paper, in a manner so truthful, that only a close inspection reveals the fact of their being copies; and so distinctly sensible even to touch are the impressions, that it is difficult to persuade those unacquainted with the manipulation that they are an emanation of the printing-press.
“The distinguishing feature of the process consists, first, in impressing natural objects—such as plants, mosses, seaweeds, and feathers—into plates of metal, causing, as it were, the objects to engrave themselves by pressure; secondly, in being able to take such casts or copies of the impressed plates as can be printed from at the ordinary copper-plate press.
“This secures, in the case of a plant, on the one hand, a perfect representation of its characteristic outline, of some of the other external marks by which it is known, and even in some measure of its structure, as in the venation of ferns and the ribs of the leaves of flowering plants; and, on the other, affords the means of multiplying copies in a quick and easy manner, at a trifling expense compared with the result, and to an unlimited extent.
“The great defect of all pictorial representations of botanical figures has consisted in the inability of art to represent faithfully those minute peculiarities by which natural objects are often best distinguished. Nature-printing has therefore come to the aid of this branch of science in particular, whilst its future development promises facilities for copying other objects of nature, the reproduction of which is not within the province of the human hand to execute; and even if it were possible, it would involve an amount of labour scarcely commensurate with the results.
“Possessing the advantages of rapid and economic production, the means of unlimited multiplication, and, above all, unsurpassable resemblance to the original, nature-printing is calculated to assist much in facilitating not only the first-sight recognition of many objects in natural history, but in supplying the detailed evidences of identification, which must prove of essential value to botanical science in particular.”
Many plans have been tried with only partial success, but that which is now in operation produces the most wonderful results. The plants are laid upon sheets of lead, and then passed through rollers, so as to leave an impression in the soft metal. The electrotype then comes into play, exact copies of the impression being taken by it. As the face of the electrotyped plate is covered with a slight deposit of some hard metal, usually nickel, a great number of copies can be taken without damaging the plate.