The Toning Bath

A very good bath is made up of one grain of ammonium sulphocyanide and one-tenth of a grain of gold to each ounce of water, or a bath sufficient to work 12 quarter-plate prints, or their equivalent of either smaller or larger sizes may be made by adding to 10 ounces of the ammonium sulphocyanide solution one grain of gold chloride. This bath, however, will be found to work more quickly if the quantity of water be reduced to 8 ounces, or even 6. The last allows half an ounce of solution for each print, which will be ample, but the active ingredients must be at full strength. One important item must be kept in mind, that is, the gold must always be added to the sulphocyanide. If this order of mixing be reversed the gold will be thrown down as an insoluble precipitate.

The toning bath having been prepared and put into one of the dishes, into it are placed all the prints, one by one, as quickly as possible, giving the dish a shake from time to time, so as to flood the solution over them. When they are all in, the bottom one is taken and placed on the top, then the next, and so on until all have been turned.

A good plan to adopt is to put the prints into the bath, film upwards, and then when turning to place the film downwards; this ensures each getting a turn. When the prints are first put into the toning bath they become brighter in colour, then gradually change, first to reddish brown and then from brown to purplish.

Care must be taken that the prints do not lie too solidly one upon the other for too long, because if the toning solution cannot circulate freely over the entire surface of the print the colour will be uneven, as the portions near the margin will tone more quickly than those near the centre, where the solution cannot reach.

The process is carried on until, upon examining the print by holding it between the eye and the light, the deep shadows are of a chocolate-brown colour. They are then rinsed in clean water, and placed in the fixing bath. They should again be turned in the same manner as when in the toning bath. Fixation is complete in about ten to fifteen minutes; a little longer will not hurt them.

Fixing

The fixing bath, is made by dissolving three ounces of hyposulphite of soda in one pint of water. A word of caution: always keep the fixing bath well out of the way - until actually required - during toning operations with the "Separate" bath, as the least particle of hypo will completely upset the whole affair.

In very hot weather it is advisable to pass the prints before toning through an alum bath (one ounce alum to twenty ounces of water) for a few minutes, take out, thoroughly rinse in water, and transfer to the toning bath. The sulphocyanide has a softening action upon the gelatine: from this cause and also from the temperature of water being high in hot climates, the hardening bath becomes an absolute necessity if the film is to be kept upon the paper at all. Even then, it is necessary to perform the toning operations in the coolest part of the day.

Washing

After fixation the prints have to be well washed, either in running water or by changing from dish to dish, as in washing before toning. They must be washed for at least one hour. It is a good plan to give them half a dozen quick changes from dish to dish with plenty of water as soon as they are taken from the fixing bath; they should then be placed in running water, or changed every ten minutes for the remaining time. It is very important that all traces of fixing salt be washed from the prints.

Fig. 43 illustrates a Siphon print washer - the tank being round and the water entering at an angle from the jet A, passes with some force down the side and round the bottom, producing a circular motion, which causes the prints to be constantly moving. The water rises up the tube, B, and falls down C, in this way setting up a siphon action, by which means the tank is freed from the water impregnated with hypo. After washing, the prints are laid face upwards on a cloth to dry in a place out of the way of all dust.

The Combined Bath

This reduces the process of toning to a very simple matter. The permanency of the print is regarded as not being equal to those toned in the separate bath and then fixed. However, if the toning is carefully carried out and the bath not forced, that is, a sufficiency of gold is used, and fixation is complete, afterwards well washing, prints will be produced that will keep for a considerable time.

Most of the baths contain lead; this will tone of its own accord, but lead-toned prints will, after a short time, assume a peculiar yellow tint; this is why a full proportion of gold is necessary.

The Combined Bath /FirstStepsInPhotography 47

Fig. 43.

A combined bath may be made up as follows: -

Bath 1

Hyposulphite of soda . 2 oz.

Alum .............. 11 oz.

Hot Water.......... 20 oz.

Borax.............. 1/2 oz.

Dissolve and allow to stand 24 hours. Pour off clear solution.

Bath 2

Gold chloride ... 3 1/2 grs. Lead acetate ... 16 Water ......... 2 oz.

For use: 8 parts No. 1.

1 part No.2. No. 2 should be well shaken

The working capacity of this bath - upon the basis of one grain of gold chloride to each 12 quarter-plate prints or equivalent - is 42 prints. It is not often desired to tone so many at one time, therefore the bath should be apportioned out for the number of prints to be toned, and that portion rejected after use.

The prints should be somewhat darker than for the "Separate" bath. They are put into the toning solution without washing, and turned in a similar manner to that previously described. When toning is complete, thoroughly wash in the same way and for the same length of time as before suggested. Ten minutes may be regarded as the shortest time for a print to fix, so that if the required colour be obtained in less than ten minutes the fixation should be completed in a plain hypo bath. No harm can be done by immersing in a plain fixer, if the operation of toning takes longer than ten minutes. It is as well to err on the right side if at all.

Bath 2 /FirstStepsInPhotography 48

Fig. 44.

"Surfacing" The Print

A highly-glazed surface may be given to a P.O.P. print by pressing it down upon a piece of polished plate-glass by means of a squeegee (Fig. 44.) The glass must be first thoroughly cleaned, and when quite dry should be rubbed over with French chalk; this is wiped off, and the glass finally rubbed with a clean soft duster. Before treating prints in this manner, it is necessary to pass them through an alum bath (one ounce of alum to one pint of water), in which they should remain a couple of minutes. If this precaution is not taken, they will adhere to the glass after drying. Should the print fail to leave the glass when dry, one corner may be raised by means of a penknife, and then by taking hold of it the print can be gently pulled. Mounting these prints is referred to under the chapter on "Mounting." If it be desired to make the glossy surface of P.O.P. dull or "Matt," this is done in precisely the same manner as above, only, in place of polished plate-glass, a piece of finely ground glass is used.

Collodio-Chloride And Albumenized P.O.P

The printing, toning and fixing may be carried out in exactly the same way as the gelatino-chloride variety.

Self-Toning P.O.P

This paper is printed in exactly the same way as the other print-out papers, but should be printed rather more deeply. The Emulsion contains the necessary chemicals for the purpose of toning, and the paper merely requires fixing. If the colour be too warm, or red, it may be rendered cooler, or purplish, by immersing the print in a salt bath - common salt one ounce, about, to one pint of water - before putting it into the fixing bath.