And now to the working and solutions.
Since the earlier editions of this brochure were published a number of other bleaching solutions have been suggested and tried. Development has proceeded in two directions - towards simplification and towards efficiency. The abolition of the sulphuric acid bath not only simplifies the process but avoids the risk of accident. The less deeply printed bromides are less likely to show a strong residual image, and so the final colour of the bromoil will approximate more closely to the colour of pigment used.
An excellent formula published some little time ago in the pages of the " Amateur Photographer and Photographic News " is as follows : Copper Bromide Bleacher.
10% solution Copper sulphate ......
10% " Potass, bromide ......
10% ,, Potass, bichromate ....
Add a few drops hydrochloric acid to clear the solution. If a bleacher ready to hand is desired, nothing will be found to work better than the Sinclair Bleacher. I have now used it for a great number of prints and have found it excellent with all prints except those heavily printed from strong negatives, such prints, in fact, as would be deliberately made for the older or ozobrome type of bleacher. Where prints or enlargements are being made purposely for bromoil and from average negatives, I prefer to keep them normal in strength and use the Sinclair bleacher. Under these circumstances I use Amidol as a developing agent, and give just sufficient exposure to render high4ight gradation, developing very slowly. Should the print be over-exposed and taken out of the developer before the developing action is completed, a good result in Bromoil must not be expected. The objection to working with hard prints is that a coloured deposit always remains in the bleached shadows, and this impairs the final result. The prints, when developed, should be fixed in plain hypo and water - an acid bath must not be used. The print, having been fixed, washed and dried as usual, may at any time be converted into a Bromoil print. Some workers have found that old prints are not so suitable as those freshly made, but I have never experienced any difficulty with prints three months old. However, this varies with the water supply. The water in some districts renders it necessary to bleach as soon as the hypo is washed out of the enlargement and before drying.
C. H. Hewitt, F.R.P.S.
FROM THE BROMIDE PRINT.
The great difference between these two prints is considerably minimised by the half tone process. In the Bromide the sky is perfectly white. The block Improves this into a tint, and at the same time reduces the value of the sunlight on the cottages in the reproduction of the Bromoil.
C. H Hewitt, F.R.P.S.
FROM THE BROMOIL PRINT.
BLEACHING THE PRINT. Immerse the print in water till quite limp and then flow over it a solution consisting of : Sinclair Bleacher .................. 1 part
Water............................ 2 parts
To make up this solution place 2 ounces of warm water in a measure, and add 1 ounce of the bleacher. Keep the dish containing the print moving till bleaching is thoroughly completed. Time depends on the make of bromide paper, some makes bleaching in 2 minutes while others may take 20 minutes. Continue the action for about 2 minutes after the action seems completed. The used bleacher is then poured into another bottle and may be used many times in succession, a little fresh being added when it works slowly. Now wash the print in several changes of water " with the chill off " for 5 or 6 minutes, and fix for the same time in : Hyposulphite of Soda .............. 1 part
Water............................ 10 parts at a temperature of 75°F. This removes the bleached image.
In the winter months and with Ilford papers I find it possible to use all solutions at a temperature of 85°F.
WASHING THE PRINT. Some makes of papers seem liable to blisters, but I have never found any trouble when working as follows. Instead of taking prints out of the fixing bath and transferring to a dish of water, I pour tepid water into the fixing bath, a jugful at a time, keeping the prints moving all the while. By this means I gradually dilute the hypo, and the gradual instead of violent change of density in the solution obviates all trouble. The print, after washing, is ready for pigmenting, and may be first dried, the gelatine sometimes being in a better condition for pigmenting if this is done. This appears to be necessary when the print is very delicate.