When the whole image has taken the ink, the picture may be touched up with a finer brush, removing excess of ink, clearing high lights, and adding more colour in places that seem to require such treatment. Lastly it is dipped once more into cold water, and clipped to a board to dry. If allowed to dry in a loose condition it will roll up and become unmanageable, probably smeary. When the gelatine surface is dry the ink is still capable of absorbing any metallic dusting powder, gold, silver, or bronze, if such things appeal to the taste of the producer. They are laid on usually from a pepper castor, and the excess brushed away with a soft camel-hair brush.
Some photographers with a talent for oil-painting use various colours on the same print, and find that they are able to manipulate the film with ordinary brushes.
Husband's Papyrotint.—This is a modification of the ordinary oil process, and is a revival of an old method of making photolithographic transfers, first introduced by Sir W. Abney. There is no great difficulty in the actual printing and development, in fact it is much easier, and requires much less manual skill than oil printing as generally understood. For the amateur it has this drawback, that the paper must be manufactured at home ; it has proved to be so perishable, even before sensitising, that it cannot be stocked as an article of commerce.
The Paper.—A cartridge or drawing paper is floated on a bath consisting of Gelatine (Nelson's Flake) . . . . . . 8 oz.
Glycerine . . . . . . . •t of Common Salt . . . . . . . . 2 ,, Water . • . . . . . . , so „ Soak the gelatine for twelve hours, then melt under heat, but do not raise the temperature much above the point • at which the gelatine is dissolved. Avoid getting bubbles on the surface of the paper. Dry the paper at a temperature of 85'.-90°, and afterwards keep in a dry atmosphere. Not more should be made at one time than will be wanted for use during the next two months. Sensitise as follows : Potassium Bichromate. . . . . .
Common Salt . . . . . . .
Potassium Ferricyanide . . . . . . 120 gr.
Methylated Spirit . . . . . . . 5 oz.
Water . . . . . . . • . 25 ,, and squeegee on a ferrotype under blotting-paper, or dry at a temperature of 8e—of course in some place secure from actinic light.
Development and Pigmenting.—Operations will be simpli fied considerably, if a piece of paper much larger than the negative is used for the print, allowing of a " safe edge " about a inch and a half all round the picture. The negative
may be put under plate glass in a large printing frame, and this edge protected by a mask of black paper. Printing is soon accomplished ; the image will print out a brown or even chocolate colour upon the yellow ground. When this is attained remove the print and let it soak in cold water for ten minutes ; next it may be transferred to lukewarm water 8o°-9o° or, if very bright prints are required, at still higher temperature ; but care must be taken not to expose the gelatine to a heat which will cause any part of it to leave the paper support. When the grain appears sufficiently coarse (which can be ascertained by lifting from the water and blotting off some portion) lay the print on a glass plate and blot off superfluous moisture.
Meanwhile a small quantity of lithographic ink, or oil colour with copal oil and a drop or two of varnish has been deposited on a dry glass plate to serve as inking slab. Mix with a palette knife two or three small dabs of oil colour or ink about the size of a pea on the inking slab, pour on a little turpentine to thin the mixture, and distribute the ink evenly well over the slab by means of a gelatine roller, such as is used in the printing trade. As the turpentine evaporates, the ink on the slab will assume a velvety soft appearance, and respond with a characteristic tacky sound to the action of the roller backwards and forwards. It is then ready for use.
The roller, duly charged with ink, is now rolled with a steady even motion backwards and forwards over the gelatine print, upon which it will leave a film of ink—at first over the whole picture impartially, but the high lights will gradually whiten. Do not use too much ink, but feed the roller with fresh ink if the image is too pale in colour. Slow rolling deposits ink upon the image ; faster rolling clears the picture. A very little practice will make perfect in the mysteries of inking up.
When the papyrotint is satisfactory, soak for a minute or two in an alum or formalise bath, and hang up to dry.
conversion of a bromide print into an oil print. Glossy-surfaced prints are not often successful, and the print should be of recent development. It is first bleached in a solution compounded very much as follows : Potassium Ferricyanide . . . . . . 4 gr.