The top of the washstand, on which the developing will be done, must be
provided with a tray of lead or zinc. Lead is preferable, as lying flatter;
but the jointing at the corners is more difficult than the soldering of
sheet zinc, which, though more liable to chemical corrosion, is much
lighter than the thinnest lead--weighing about 1-1/2 lbs. to the square
foot--that could well be used. If lead is selected, the services of a
plumber had better be secured, if the reader has had no experience in
"wiping a joint."

A zinc tray is prepared by cutting out of a single sheet a piece of the
shape shown in Fig. 12. The dimensions between the bending lines (dotted)
are 1/8 inch less in both directions than those of the shelf. The turn-ups
a, a, b, b, should not be less than 1-1/2 inches wide. Allow half an inch
at each end of b b for the turnover c. Turn a a up first, then b b, and
finally bend c c round the back of a a, to which they are soldered. A drop
of solder will be needed in each corner to make it water-tight. When
turning up a side use a piece of square-cornered metal or wood as mould,
and make the angles as clean as possible, especially near the joints.

[Illustration: FIG. 12.--Showing how the tray for sink is marked out.]

A drain hole, an inch or so in diameter, is cut in the centre of the tray.
To prevent the hands being injured by the tray, the front should be covered
by a 1/2-inch strip of zinc doubled lengthwise, or be made a bit deeper
than 1-1/2 inches in the first instance and turned over on itself.

Before the tray is put in position the basin hole must be filled in, except
for an opening to take the waste pipe. The plug is pad-sawed out of wood of
the same thickness as the top, to which it is attached by crossbars on the
under side. The whole of the woodwork, or at least those parts which are