259. Sinks. It is best to conduct all opera tions with liquids in a large sink. This can be made, for example, of wood, 2 lined inside with lead (all joints must be welded, not made with tin solder) or slate. Cement sinks are to be avoided ; they are cheap, but do not last long ; earthenware sinks are usually too small. The bottom of the sink should always be on a slope, to allow all the water to flow away through the waste pipe (Fig. 158).
The sink is provided with a wooden rack from one end to the other, fitted with triangular rods, so that it makes very little contact with the bottoms of dishes, and consequently does not wet them appreciably.
The internal dimensions of the sink should be such that it will hold side by side the dishes used in the various operations. The sink may he extended on one side or the other by plat forms where stock solutions can be mixed. The platforms should preferably be made of imper meable material, or be rendered impermeable, and should have grooves draining into the sink to prevent water collecting on them.
A bamboo rail running above and a little in front of the top of the sink provides something for the operator to lean on, and prevents his is used, steps must be taken to avoid confusion, during working, between the switches operating the white light and those operating the safe lights. The switches for the white light may be operated by removable keys, or may be placed higher than the others, or be of a different design and material.' To avoid dazzling the eyes and rendering them slow in getting accustomed to the safelight, any wetting his sleeves or clothes against the sides of the sink, which are always damp.
Water should be laid on, if possible, from two taps one supplies the washing tank and is arranged at one end of the sink, while the other, near the centre, is used for mixing solutions, rinsing, etc. 2 It is well to choose taps of a long neck pattern, and to fix them so that they project from the wall to about the middle point of the sink, placing them at a height such that they allow the passage under them of the tallest vessels used when standing in the bottom of the sink or on the grid. 3 The waste pipe should preferably be covered with a perforated dome-shaped cap, to prevent its stoppage by odd pieces of film or paper. 4 The waste pipe should also be provided with a siphon, with an inspection plug at each bend, in case the pipe becomes stopped up.
260. White Light in the Apart from the safelights for the dark-room, which we have studied in Chapter XIX, there must obviously be ordinary lighting, chiefly for clean ing, getting things ready, and examining nega tives, etc., after fixation. Where electric light
white lights in the dark-room should be provided with ground glass or opal diffusers, so as to render the filaments or flame indistinguishable. The lamps should be arranged as high as possible so as to be out of the direct field of view.
261. Equipment of the It is a good rule that the dark-room be used only for operations which cannot be performed except in non-actinic light. An extra " work-room " should be provided, with a sink and one or two tables and cupboards, for any work which can be done in white light, e.g. weighing chemicals, preparing baths, intensification and reduction of negatives, toning, and washing 2 prints, and drying. But let it be borne in mind that neither of these rooms, where the atmosphere is always somewhat damp, is suitable for keeping stocks of plates, papers, etc. There should, however, be one or two drawers in the table, for use when loading slides, for opened packets, and sufficient material to last the day only.
The table used for loading and unloading slides should be far enough from the sink to be out of the range of any splashes, and not in the direct rays of the lamp. In a very small room, a folding table with a cloth cover can be used, being erected only when required.
The dark-room should contain only absolute necessaries in order to facilitate working in the dim light. All useless shelves and cupboards should be vetoed ; they only encumber a dark room and make it difficult to keep it clean. A rack suitable for draining dishes under the sink, a shelf above the sink for bottles of solutions, and under this shelf a rack containing notches to hold measuring and other glasses upside down, form, with the table for loading dark slides, the only necessary equipment of a dark-room used for negative-making.
If printing on development papers is to be done in the same room, there must obviously be provided a printing box and a cupboard for the printing frames and opened packets of papers. If no other room is available, there is also the enlarger to be included, which may, however, be of the vertical type, and thus save space.
For ease in cleaning, avoid securing to the walls any fittings which can remain unattached. For the same reason, tables and shelves should be painted with some washable preparation, or covered with linoleum, so that they can from time to time be sponged with a wet rag. It is even well to get rid of sharp corners in the room by nailing into them strips of wood of triangular cross-section.
A soap dish above the sink and a roller towel on one of the walls should not be forgotten. 2