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.
The following is a memorandum of my equipment:
1029. I use a No. 3 Folding Pocket kodak, fitted with a Goerz lens, 5 inch focus. I use N. C. films for my negatives, and develop with a developing machine. I use Pyro powders for developer. The paper I use for enlarging is Royal Bromide, developed with Rodinal (no Bromide).
1030. I make all my enlargements by daylight, in a room containing one window, fitted similar to the illustrations shown in this volume. For an easel, however, I use a regular printing-frame; placing my Bromide paper in the printing-frame, with the back clamped on firmly. This holds my paper perfectly flat. I place the printing-frame upon a box, and, in order to hold the printing-frame perpendicularly, I place another small box back of it. The printing-frame is stood on edge upon the large box, and placed on a line with, and directly in front of, the enlarging camera, the latter being arranged in the window. The box containing the printing-frame, or, in short, my easel, is moved backward and forward, to or from the camera until the desired size and focus is obtained.
Variations. I sometimes use silk bolting-cloth placed in contact with the paper, or at some distance from it, according to the diffusion desired. This is a matter of one's own judgment, and depends upon the subject and negative used.
Exposure. The exposure given varies from 1 to 20 seconds. I invariably use test strips before exposing a full sheet, and these strips are the full length of the size sheet I expect to use, and placed diagonally in the printing-frame. The test is taken by exposing the paper in sections, using an ordinary card before the exposed paper. The first section is exposed 5 seconds; then I move the card over a little farther and give another 5 seconds exposure, and so on until I have five exposures on this strip, one of which will have 25 seconds; another exposure 20 seconds; a third, 15 seconds; a fourth, 10 seconds, and the last, 5 seconds. This test strip is then developed, and the exposure on the section giving the best results is the amount of exposure I use for my final exposing from this negative. I use Rodinal without Bromide entirely, for my developer.