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.
480. Eastman W. D. Paper. - The W. D. Platinum Paper, manufactured by the Eastman Kodak Company, is a paper not unlike the regular platinum paper, and on which pure platinum and absolutely permanent tones can be obtained. It is especially adapted for the amateur, on account of its extreme simplicity of manipulation, as it requires nothing but water and acid for the entire process of development and clearing. When using this paper follow the instructions which are furnished by the manufacturer and accompany each package. We would call your attention to the following points, which must be remembered:
Effect Of Moisture. "Water-Tone" Platinum Paper is very easily affected by moisture; it will, therefore, be necessary to exercise care when printing in damp weather.
482. Print by direct light (sunlight preferred) until the shadows are clearly outlined in a deep canary color. At this stage the same detail will be observed in the half tones that the finished print will show. For developing, use plain water, heated to 120° (which will be as hot as the hands can bear).
483. The development will be practically instantaneous, and care must be taken to avoid air bubbles forming upon the surface of the prints. Place the prints, after developing, directly into a clearing bath of muriatic acid, one dram to twelve ounces of water, and let them remain in this bath about ten minutes, when they are ready for the final washing of fifteen minutes in running water, or five changes of about three minutes each. Lay out between blotters to dry and mount by applying paste to the corners.
Keeping The Paper In Good Condition. This paper is put up in tin tubes and sealed with rubber tape. This is to prevent the air from coming in contact with the paper and to keep it free from all moisture. If the can is left open for any length of time the air will affect the paper to such an extent that it will be almost impossible to produce good prints.
485. The effect of dampness is a lack of vigor, a general muddiness of the tones, and where the paper has been exposed to its influence for some time it injures the purity of the whites. The paper will keep for months, but must be stored in a cool, dry place, in the cans in which the paper is supplied. When paper is removed from the tube, see that the sheets not intended for immediate use are returned to the tube and the tube again carefully sealed with the tape.
Depth Of Printing. It will require a little practice to be able to print to the proper depth. The paper should be printed only until the image is fairly visible, and then developed with hot water, no chemicals being needed. As this paper is easily affected by moisture, it will be noticed that in warm, damp weather the print will show quite a tendency to print out black in the deep shadows. Pay attention only to the high-lights, as the same amount of printing is necessary as on dry days. In fact, in damp weather you must print a trifle stronger than in dry weather.
Clearing Bath. The muriatic acid used in the clearing bath must be chemically pure or yellow whites will result. The necessary developing cheimcals are already in the paper. Never use any hot water which contains iron rust, as this iron rust will cause black specks on the paper. Care must be taken to avoid air-bells forming on the surface of the print. If they occur and they are not broken at once white spots will be produced. Remember:
1. That the paper must be kept dry at all times.
3. When developing slide the print face side up into the hot water, so as to prevent the formation of air-bells. If any air-bells should form, break them at once by touching with the tips of the fingers.
4. Prints must be placed directly from the hot water into the acid clearing bath without previous washing.
5. The last clearing bath must be free from all yellowness; then you can feel sure that your prints are cleared thoroughly.
6. Chemically pure hydrochloric acid (muriatic acid) must be used in the clearing bath, and a fresh bath must be used for each batch of prints.
Mounting. Prints may be mounted solid in the usual way, by using any good starch paste, and bringing the print into contact with a print roller. Usually these prints look better when only pasted at the edge. In order to do this they must be first dried by mopping off the surplus water and then placing between blotters for several hours. Usually it is best to place them in the blotters, and after changing to dry blotters once, allow them to remain over night. The following morning they will be dry and flat ready for pasting to the card or mount.
489. A good method of development is to hold the print over steaming water until development is nearly completed and then immerse for a few seconds in hot water. This method gives particularly rich, brilliant prints.
490. When negatives are under-timed or weak thin negatives are to be printed from, strength can be gained by printing under blue glass; printing in the shade will also add to the brilliancy of prints from such negatives.