Printed on Ilford P.M.S Bromide Paper.

Printed on Ilford P.M.S Bromide Paper.

Belitski's Reducer

If the ferric salt can be conveniently obtained, this reducer surpasses all others for bromide prints. No stains are likely to result from its use - in fact it will often remove developer stains - and it does not alter the original colour of the print. One fault is that it must not be exposed to daylight, but keeps for a long time in the dark.

Potassium Ferric Oxalate......50 gr.

Sodium Sulphite . . . . . . . . 40 „

Water..........5 oz.

Add 10 gr. of oxalic acid when the above are dissolved, stir well, and decant off the green solution, to which must then be added about 250 gr. of Hypo.

Toning Bromides

Bromides may be toned with uranium, copper, iron, and other methods, most of them rendering the permanence of the print subjected to them very questionable. The sulphide toning process, converting the silver image into the practically unalterable silver sulphide, bears at present a good reputation. A hot bath, which will serve for several kinds of paper, is made up as follows:

Hypo....... 1 1/2oz.

Alum..........80 gr.

Water..........10 oz.

The bath is made up with hot water, and 5 mm. of nitrate of silver solution are an improvement, serving as a restrained The solution should be allowed to cool and then warmed again to 1200 Fahr. for use. If any precipitate settles on the prints it must be wiped off with cotton wool. Warm brown tones are given.

In the Kodak formula for sepia tones, 1 oz. hypo is dissolved in 7 oz. water at 1350 Fahr., and 130 gr. alum added by degrees while still at the same temperature. The liquid will be milky, but must not be filtered. After the prints have been fixed and washed, they should be placed in a saturated solution of alum for ten minutes and allowed to dry. The actual toning is carried on by immersing the prints in an iron dish containing the cold hypo-alum solution, which is then raised to 1200 or 1250, and kept at that heat for twenty minutes, or until the desired tone is obtained. The fumes of these hot alum hypo baths are very injurious both to dry plates and papers, and this toning process should not be carried on in any apartment where they are stored.

Bleaching Process

Bleach the print in:

Potassium Bichromate....... 10 gr.

Hydrochloric Acid ........ 5 min.

Water.......... 1 oz.

Wash with several changes of water until yellow stain is discharged; a little alum will hasten the effect. Then either leave to print in the sun or redevelop with either rodinal or amidol. The brown image may then be toned in any ordinary gold toning solution, after which the print may be reduced in the fixing bath if necessary.

Alternative Bleach For Sulphide Toning

Bleach the print in:

Ammonium Bromide.......50 gr.

Potassium Ferricyanide . . . . . . . 150 "

Water.......... 10 oz.

Wash well in several changes of water, and then tone to tint desired in a solution of pure sodium sulphide 15 gr. to the ounce of water.

Platinum Toning

Bromide prints (but not gaslight prints as a rule) may be toned in a solution of platinum perchloridc. They lose density to a considerable degree while under treatment, and must therefore be allowed to over-develop. The colour will vary according to the proportions of platinum salt and acid in the toning bath. For sepia tones:

Platinum Perchloride....... 2 gr.

Hydrochloric Acid.......60 min.

Water..........10 oz.

Gaslight Papers

A series of new papers, known under such names as "Velox," "Gravura," "Slow Contact Paper," etc., etc., have been gradually taking the place of bromide paper for contact printing by artificial light. The principle of most of these is an emulsion consisting chiefly of the chloride and other salts of silver which are scarcely sensitive to any rays of light except those between F and H on the spectrum, viz. the blue and violet. They are nearly all white in colour, and not of creamy tint like the bromide papers. These papers therefore do not need the use of a dark room, and may be manipulated within a few feet of the gas-burner by which the picture is printed, such light being comparatively poor in blue and violet rays. The most convenient arrangement is to shelter the developing dish behind a large sheet of cardboard or other light screen on the table, say, six feet from the source of light.

There are many ways of working these papers, and it is not easy to give directions that will apply alike to all the brands that have attained to popularity. Some photographers prefer to give a very long exposure to light - two or three minutes - and develop in the much-diluted formulae adopted for bromide papers. By this means it is possible to secure very great softness of detail, and also a range of colours from light brown to rich chocolate, black, and even blue. The more common practice is to expose for a shorter time and use a stronger developer.

Development

The development of gaslight papers is much the same as for bromides, except that the developer must not be poured off the print until it is ready to be transferred to the fixing bath; the developer will oxidise in the paper if exposed to the air. Development is often complete within a minute, when the liquid must be poured off and the picture very quickly rinsed in water. The developer must always contain a small proportion of bromide solution. Two typical formulae are given, the first that for the Ilford, the second for the Gevaert gaslight papers.

(1) Metol..........5 gr.

Sodium Sulphite........1/2 oz.

Hydroquinone . . . . . . . . 20 gr.

Sodium Carbonate (crystals)..... 1/2 oz.

10 per cent. solution Potassium Bromide . . . 10 min. Water....... . . . 10 oz.

(2) For warm tones. The time of exposure may be prolonged or curtailed, in order to obtain a range of colours.

Slock Solution

Glycin .......... 1 oz.

Sodium Sulphite........ 2 1/2 ,,

Potassium Carbonate....... 5 „

Water, distilled and hot...... 4 "

Dissolve the sodium sulphite first, then add the glycin, and lastly the potassium carbonate in small quantities as the mixture froths up. A 20-oz. measure should be used for the above quantities. The result is a liquid of creamy appearance and consistency, which must be shaken before use. To develop take:

Stock solution........ 1/2 oz.

Water......... 15 ,,

Potassium Bromide (10 per cent solution) . . 7 drops.

Rodinal is also a favourite developer with gaslight papers in the proportions of 1 to 30 or 50.

Phosphate Papers

These papers, while produced and completed with a rapidity greater than the ordinary gaslight papers, have all the appearance of gold toned P.O.P.

"Ensyna," the earliest of these, can be finished off ready for drying and mounting in about six minutes, divided as follows:

Exposure....... about 30 sec.

Water bath.........1 min.

Development........2 „

Fixing.........30 sec.

Washing.........2 min.

The film is very soluble, hence the short time allowed for fixing and subsequent washing.1 The tones may vary according to length of exposure from engraving red, brown and sepia to blue-black; over-exposure merely imparts a warmer tone to the print.

The Paget Phosphate Paper is developed with an acid metol developer, the proportions of which are varied to increase contrast or to alter the tones which may range from blue-black to purple and sepia. The prints undergo no alteration of tone in fixing, which is rapidly completed, and the last washing need not occupy more than half an hour. When fully exposed, the tones are similar in appearance to those produced by toning P.O.P. with gold.

1 Further experiments have shown that a more prolonged washing in running water is necessary to eliminate hypo entirely from the paper. A weak solution of potassium persulphate would, however, obviate this.