The printing is not carried quite to the usual intensity, as the half-tones are very little dissolved in this process.
On being taken from the frame, the prints are washed thoroughly in common water until it ceases to become milky; that is, until the greater part of the Nitrate of Silver has been removed. The washing must be conducted in a dark place, but it is not necessary to hasten it; the proofs may be thrown into a pan of water covered with a cloth, and allowed to remain until required for tinting.
A trace of free Nitrate of Silver usually escapes the washing; this would cause a yellow deposit on the Print, and also in the toning Bath. It must therefore be removed, either by adding a little common salt to the water during the last washings, or by means of a dilute solution of Ammonia.
For plain paper Prints the former plan will be found the least troublesome; but with Albumen proofs[51] the Ammonia is required, in order to dissolve away a portion of the Albuminate of Silver which has escaped the action of light, before submitting the print to the gold; otherwise the dark tones would nearly disappear in the fixing Bath, the Hyposulphite carrying away the Gold with this superficial layer of silver salt.
[51] The amateur is recommended not to use Albuminized paper in this process until he has become accustomed to the manipulations; the plain paper prints being toned with more ease and certainty.
To prepare the Ammonia Bath, take of
| Liquor Ammoniæ | 1 | drachm. |
| Common Water | 1 | pint. |
The exact quantity is not material; if the liquid smells faintly of Ammonia, it will be sufficient. Place the washed Prints in this Bath, two or three at a time, and allow them to remain until the purple tint gives place to a red tone. The action must be watched, because if the Ammonia Bath be strong, the proof becomes unusually pale and red, and when this is the case a little brilliancy is lost in the after-tinting.
As the Print is comparatively insensitive to light when the excess of Nitrate has been washed away, it is not necessary to darken the room; but a bright light proceeding from an open door or window should be avoided.