reating the prints by mixing the above stock with water, as
follows: _Sulphide toning bath._--Stock 20 per cent solution 3 ounces;
water to make 20 ounces.

This makes a bath which contains about one per cent real sulphide,
corresponding with about a 3 per cent solution of the sulphide as
purchased. If the bath is much weaker, the tone obtained is usually not
quite so good; while, if it is stronger, there is danger of the print's
blistering while toning, or afterward in the washing water. Indeed, some
papers need to be toned in a weaker bath, and require also to be fixed in
an alum-hypo fixing bath (see later), so that the strength of the toning
bath given above may be taken as the maximum, and used at half or
one-third strength, as circumstances show to be necessary. And, to repeat
the caution once more, the toning bath is to be thrown away as soon as the
prints have been passed through it. With these points in our mind as to
the making up of the solution, we can come to the process proper.

The prints require to be well washed and free from hypo before being
placed in the bromide-ferricyanide bleacher, because any hypo in
conjunction with the ferricyanide will form the well-known Farmer's
reducer, and cause patchiness of the prints. It is immaterial whether the
prints are taken direct through the toning process or dried in the
meantime. Some workers contend that the toning process is more regular if
the prints are dried before bleaching. In either case, immersion in the
bleacher will cause the fully developed bromide to disappear, leaving only
a faint brown image behind. In some cases the image is fainter than in
others, the difference appearing to depend chiefly on the developer
employed. Developers with a liability to stain will give prints which do
not bleach out so completely as those made with cleaner working
developers. But, in all cases, two to three minutes' action of the
bleaching solution will be ample; if all pure black is not gone in this
time, it is a sign that the bleach is becoming exhausted. The prints
should be kept constantly on the move whilst in the solution, and turned
over and over to ensure equal action. They are then given quite a brief
rinse in running water--half a minute to a minute--and then transferred to
the sulphide solution, where they should darken to the full brown or sepia
tone in a few seconds. It is well always to leave them here for twice to
three times the period required to give