There are two methods employed for obtaining facsimiles of ferns, leaves, sea-weeds, one suited to the amateur, the other for commercial purposes.
(a) For the former the requisites are small quantities of coloured printing inks, black may be used, but the natural colours look much better, a little cotton wool, and some pieces of very soft wash-leather. Either fresh or dried leaves may be used; the former require no preparation, the latter should be dipped in water, and then left between damp bletting paper for some time to become tough, or they sometimes crumble to pieces during the manipulation. A dabber about the size of a marble is made of cotton and soft leather tied up, a small quantity of ink of the desired colour is put on a piece of glass, and the dabber is covered with it, using as little as possible. The side of the leaf from which the impression is to be taken is then laid, face upwards, on a piece of clean paper, and the dabber is employed lightly to coat all the prominent parts of the leaf with the ink. The leaf is then laid, ink side downwards, on a piece of moistened paper, covered with another similar piece, which may be kept in place by lead weights if necessary. The part under which the leaf remains should then be carefully pressed with a dabber, similar to that used for the ink, taking care to go steadily and evenly over the whole surface of the leaf.
Of course it is necessary to take great care to prevent the leaf or paper from shifting. Any number of impressions may be taken from one leaf. Inks may be mixed with a small palette knife to obtain any shade of colour, and two or more colours may be used on one specimen. (b)In the commercial process, the leaf, or other object, is placed on a steel plate, and covered with a leaden plate scraped bright; it is then subjected to great pressure, which leaves a beautiful impression on the lead. From this a copper matrix is taken by the electrotype, which in turn serves to produce an intaglio plate in copper, from which impressions may be taken in the usual manner.
(c) A piece of writing paper is moistened with olive oil and thoroughly smoked over the flame of a tallow candle, the leaf, which should be dry, is laid upon it, covered with a piece of paper, and well dabbed all over, then transferred to a piece of clean paper, and the dabbing is repeated, when it will leave an impression much like a very delicate pencil drawing.