Bromoil printing and bromoil transfer

by Emil Mayer

Oil and bromoil printing are, therefore, nothing more than the two methods which have hitherto been at our disposal for the production of a tanned image in gelatine.

Both methods lead to the same result; only the bromoil method is by far the more complete technically, as is shown in the following discussion.

In oil printing, printing is effected direct on a bichromated gelatine film. The chromate image is only faintly visible and is not easy to judge. From its nature it has a very short scale of tones and, therefore, only gives satisfactory prints from soft harmonious negatives, while with more contrasty negatives it must inevitably fail; if with such negatives the high lights are correctly printed, the shadows have long lost all details; if the shadows are correctly exposed, the high lights are wanting in detail. Control of the chromate image is only possible to a very moderate extent. This chromate image is washed out and leaves behind as a result the tanned image in the gelatine, in which all the disadvantages of the short scale of tones are inherent, and which besides this can be far less easily inked-up than a tanned image prepared by the bromoil method.

The process of bromoil printing has been fully explained in this book; a direct comparison of the two processes will be made very briefly. A correct print is prepared on a suitable bromide paper, either by contact or enlargement. Through the possibility of using direct enlargement, the enlarged negative, necessary in oil printing, is done away with. The bromoil image, in contradistinction to the chromate image is visible, and can be controlled in the most varied ways to attain the desired artistic effect. It has a much greater scale of tones than the chromate image; and this can in addition be increased in the subsequent processes far beyond the possible gradation of the bromide print. The resulting bromide image is then removed by a bleaching solution containing bichromate, and in this way the tanned image is formed in the gelatine.

Oil printing and bromoil printing, therefore, lead to the same result; but the tanned image, obtained by way of the bromoil print, is qualitatively of much greater value, for it has a much better gradation.

The opinion is frequently expressed that it is a specific property of the oil print to give pictures of a peculiarly artistic character.

It is, however, absolutely erroneous to assume that the same effect cannot be obtained in a bromoil print. As already mentioned, the tanned images produced in the two methods are alike, but the bromoil print may have a far longer scale of tones.

The rich gradation of the bromoil print is however not present from the beginning, but is only produced by allowing it to swell in water of suitable temperature. The warmer the water used, the longer is the scale of tones, naturally within definite limits.

In bromoil printing it is therefore entirely at the choice of the operator whether he will or will not make use of the long scale of tones which the process can give.

If cold water is used for the soaking, the gradation of the tanned image is much less than that of the oil print or the bromide image. By the choice of a suitable temperature of the water, the short gradation of the oil print with all its peculiarities can be exactly obtained. With higher temperatures the gradation may be finally increased far beyond that of the original bromide image.