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. After using the salt or the Ammonia, soak the Prints again for a minute or so in common water. Then place them in the toning Bath of Gold and acid; do not put in too many at once, and move them about occasionally, to prevent spots of imperfect action at the point where the sheets touch each other. The foreign papers, plain salted, colour rapidly in two or three minutes. English papers require five to ten minutes; Albuminized, ten minutes to a quarter of an hour. The tendency of the Gold Bath is to give a blue tone to the image; hence proofs which are light red after using the salt or Ammonia, become, first red-purple, and then violet-purple in the Sel d'or. Albumen Prints assume some shade of brown, or of purple if not too strongly Albuminized. Ammonio-Nitrate papers highly salted, and prepared without Citrate, become first dark purple, and then blue and inky; the Citrate is intended to obviate this inky tint. When the darkest tones are reached, the Bath produces no further effect, but eventually (more especially if the solution be not shielded from light [?]) there is a little decomposition, producing a cream-coloured deposit upon the lights. The toning being completed, the Prints are again washed for an instant in water, to remove the excess of gold solution. This washing must not be continued longer than two or three minutes, or there will be danger of yellowness of the whites; this however ought not to happen with proper precautions.