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.
Floating The Paper On The Bath. Care is necessary in floating the paper on the bath to avoid the formation of air-bubbles. Each air-bubble, unless destroyed as soon as it makes its appearance, will cause a white spot in the finished print. The air-bells on the sensitizing bath prevent that part of the paper underneath the air-bell from coming in contact with the silver bath; consequently, that spot is not sensitized and, of course, will not print, resulting in a white spot.
Laying The Sheet On The Bath. Take a sheet of paper and after rubbing it with a piece of absorbent cotton, as described above, catch the sheet at the two diagonal corners between the thumb and first fingers. Bring the two ends quite close together, slightly curving the paper; lower the end furthest from you into the silver bath, and continue gradually lowering the sheet until it is all on the bath. See Illustration No. 52, Vol. I.
22. Searching for Air-Bells - After the paper has had a chance to settle nicely upon the bath, requiring but a few moments, catch the paper by one corner of the sheet, raise it to the center and examine. If there are any air-bells on the surface break them with the point of a toothpick or tuft of cotton. Lift all four corners and examine in like manner. After all air-bells have been removed, float the paper for the required length of time. In summer months, usually 60 seconds is sufficient; in winter, or in cold climates, from one and a half to two minutes will be required. With a weak bath the paper does not require as long silvering as with a strong bath-usually one-third more time is allowed for a strong bath-the average being from one to one and a half minutes.
Removing The Paper From The Bath. When the sheet has been floated the required length of time, catch it by the two near corners, between the thumb and first finger of each hand, and draw it carefully over the glass rod and place, face side down, on a clean sheet of blotting paper. Cover with another sheet of blotting paper and gently rub with the hand. Next, prepare your second sheet for sensitizing, in the manner previously described, and while the second sheet is on the bath, remove the first sheet from the blotter and place in the drying box.
Drying Paper. While the process of sensitizing may be done in subdued daylight, the drying of the paper must be done in a darkened room or closet. A very convenient drying box-suitable for drying 24 sheets-may be made as follows:
25. Build a square box 24 inches deep, 30 inches wide and 36 inches high, and for convenience build the box 18 inches from the floor. In the center of the inside of the top of this box, and running across the 30-inch way, draw a line and insert along this line, one inch apart, screw hooks upon which to suspend the paper. On the front of the box have a large door 20 x 36 inches. In the bottom of the box a dozen or more 3/4 inch holes are bored to give ventilation. Fully a half hour before you are ready to dry the paper, place in the box a No. 2 burner oil-lamp and close the door. The heat from the lamp will heat the box to a sufficient temperature to dry the paper in 15 minutes.