Bromoil printing and bromoil transfer

by Emil Mayer

The fact that the bromoil print is trimmed before being placed on the pad has caused some nervous souls to be afraid that water may thus come from the support through the brush on to the film, but this is not likely to occur. The pad should be arranged by first laying on the glass plate a thoroughly wet copying sheet; on top of this a second sheet is laid, equally wet and with no air-bubbles between. The water is completely dried off the surface of the second sheet with the aid of a sheet of lintless blotting paper, and then one can work all day long even in summer in the greatest heat without changing the support; there will always be enough moisture to produce adhesion between the sheet and the support, but one will never carry a drop of water on to the print with the brush.

The Choice of the Paper.—The pigmented gelatine film gives up its ink when it is brought into contact with paper under pressure; from which it seems that theoretically paper of any quality may be used for the transfer. In practice the matter is not quite so simple, for every paper surface possesses an individual character which definitely influences the ink transfer and the final result.

Papers may be roughly classified as rough, medium and smooth, obviously with many intermediate grades, each of which may be divided into sized, half-sized and unsized sorts. Whether a rough, medium or smooth structure is to be chosen, must be decided from a purely artistic point of view, and in this decision the character of the subject and the effect desired are of equal importance. It is different, however, as regards sizing. The quality of the picture frequently depends on a correct decision on this point. This is at once clear when we consider that unsized paper is much more porous than half-sized or fully-sized paper, and thus can remove the ink much faster and more completely from the bromoil print. If, for example, a bromoil is transferred with a certain roll pressure on copper-plate paper, that is, on a very absorbent porous paper, the ink will be quickly transferred to it, whereas a sized paper, under the same conditions, that is, with the same pressure on the rolls, will take up only a small part of the ink. A comparison of the two transfers would then show that the shadows on the copper-plate paper are blocked up and have lost many details, while those on the sized paper appear much too light, which is readily understood, as the porous paper has taken up all the ink, the sized paper merely a portion of it.

How far these properties of papers can be equalized or used will be dealt with in the section on “Printing.”

In choosing the paper destined for the transfer, therefore, attention not only has to be paid to the structure, which must serve the artistic purpose, but one must be certain of the amount of sizing; this latter is necessary so that one may correctly carry out the actual printing process.

As a basic principle the worker should use only pure rag paper and avoid all paper containing wood pulp. Although theoretically it cannot be disputed that any paper is suitable for transfer, it is also practically accepted and undoubtedly correct that beautiful prints can only be prepared on good papers, and the artistic photographer should not be induced by any consideration to use other than the best materials.

All the commercial drawing and water-color papers of all tints and structure, made by reliable firms, can be recommended. Extraordinarily fine results are obtained on copper-plate printing paper, which may be obtained in white and yellowish tints. Equally as good, and specially suitable for certain effects, are the Japanese and Chinese papers.

The stock of paper should be kept in a dry place and free from dust.

Printing should only be effected on dry paper. Damp paper is used when it is very coarse-grained and rough, as then the ink is more easily taken in the depressions. Such sheets are best dampened by immersing them for some minutes in water, allowing to drain and passing them through the machine between two sheets of calendered lintless blotting paper with strong pressure; they are then immediately ready for printing.

If one has to deal with very absorbent papers, with which, especially in the pure whites, there is always danger that in spite of careful printing the gelatine film may adhere to the surface of the paper and thus spoil both bromoil print and transfer paper, the paper should be given a slight sizing. The preparations to be used for this should be those used by the gum printer: gelatine hardened with alum, chrome alum or formaldehyde. But these solutions must be applied warm and then the original brightness of the paper suffers. It is, therefore, more advantageous to use the cold preliminary coating recommended by von Hübl to prevent the sinking-in of the platinum-iron solution for platinotype; 2 g (60 gr.) of rice or wheat starch or arrowroot should be rubbed up with a little water and added with constant stirring to 100 ccm (3 oz.) of boiling water. When quite cold the solution should be applied evenly to the paper with a swab. The application must result in a slight matt gloss on the paper without any damp places anywhere. When dry it is ready for use. The longer the paper is kept after this preliminary preparation, the better it is.