This section is from the book "Complete Self-Instructing Library Of Practical Photography", by J. B. Schriever. Also available from Amazon: Complete Self-Instructing Library Of Practical Photography.
Printing From A Soft Negative. A soft or quick printing negative prints only on the surface, unless it is exposed and printed in the shade, and even then it should be carried farther than a hard printing one, as prints from soft negatives lose strength in washing.
Washing. Platino or matte surface prints should be washed in practically the same manner as glossy collodion, as platino is also collodion coated, but with a matte surface. Eight or ten changes, handling each print separately between each wash, is generally enough. It is, however, quite important that these waters be all of one temperature. Never allow the fingers to touch the face of prints before they reach the first washing, otherwise you will experience difficulty with red spots. When you are ready to wash the prints, gather them face down on the cover of a regular paper box, as described in Chapter III (How To Proceed), paragraph 48, Glossy Printing and Toning, and having provided a tray half filled with water, slide the prints into it, one at a time. It is a good plan to add an ounce of saturated solution of borax, or one-half ounce carbonate of soda solution, to every gallon of water used in the first wash water. This is done to neutralize the water. Should the water be alkaline in itself, this is unnecessary. After the first change of water which contains the alkali, wash in six to eight changes of clear water, or until you have eliminated the free silver and preserving chemicals. Unless these chemicals are properly removed from the prints they will not tone evenly.
Washing Old And Fresh Paper. The paper when you receive it, if fresh, is in an acid condition from the chemicals used to preserve it. As the paper ages the preserving chemicals evaporate and weaken, and as the paper grows older, the amount of acid remaining in it is reduced considerably. Therefore, fresh paper containing much acid must be washed more thoroughly than if it was old. You must remove the acid and preserving chemicals from the paper before toning, as your gold bath is an alkaline solution and must be kept in this condition while toning all prints. Should you fail to remove all these acid properties from the print before they enter this bath, the acid would in time change the bath from alkali to acid, and the prints would not tone but would bleach.
Flattening Matte Paper Prints. The chief success in working any and all collodion matte or gloss papers, without curling or breaking at the edges, lies in the proper flattening of the prints, and this is a very simple matter, but must be carefully done. Always use a good sized, smooth bottom tray for flattening the prints. Pour water into this tray to the depth of about one-half inch. Place your prints, one at a time, into the water by sliding them in, one on top of another, keeping them flat on the bottom. Be sure that each print is thoroughly wet before another is placed on top of it. The prints must not be placed in a regular pile in the tray, as this would allow the edges to curl over each other, but should be piled irregularly over the entire bottom of the tray, partially over-lapping one another. After all the prints are in, pour off the water and with your hand squeegee and flatten the prints to the bottom of the tray. (See Illus. No. 5, Page 47.) Now add more fresh water and rock the tray for about five minutes, but do not pick the prints over. By adding this water and rocking the tray you will avoid red streaks. Pour off the water and again press down the prints with the flat of your hand. Set the tray on edge and allow the water to drain from the tray for about five minutes. Next pour plenty of water over the prints and proceed to wash by separating and picking them over and over. After flattening, prints may be handled face up. This will be found a distinct advantage, as the fingers will slip easily under the edges of the print, avoiding abrasion of the edges and also preventing rubbing the surface of the print.