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.
Note. Many of the difficulties which may be encountered in preparing the work of this lesson are from the same cause as whose given in previous instruction, and in case you meet with any difficulty for which no remedy is given in this particular lesson, refer to the index, which will direct you to the lesson and paragraph wherein you will very likely find your difficulty, prevention and remedy. Only such difficulties as are not covered in previous instruction will appear in this department.
Applying Dope. The dope should be applied by placing one or two drops on the center of the face of the negative, and this rubbed in a circular motion with a very small tuft of cotton or the tip of the finger. Gradually work outward, then back toward the center and outward again, until the dope has become very nearly dry, or until it becomes very tacky. Be careful to avoid any line forming at the outer edge of the area covered by the dope. If in applying the dope you gradually work outward from the center there will be no perceptible line at the edge of the space covered by the medium.
Applying Varnish. The greatest difficulty that will occur when applying varnish to the negative will be caused by pouring from a bottle having too small a mouth. Always keep the varnish in a wide-mouthed bottle. Hold the lower left corner of the negative in your left hand. Pour just enough varnish on the farther right-hand corner to gradually cover the plate. Tilt it first to the left, so that the varnish will run into the farther left-hand corner; then tilt toward you, and finally to the right, allowing the varnish to run off into the bottle at the right-hand corner nearest you.
Line Around Edge Of Dope. This will be caused if you do not apply the dope in a circular motion and gradually work outward from the center. With a little practice you should experience no difficulty in this respect.
Cannot See Imperfections. (c) You are sitting too close
to the negative, and you see the pencil stroke but cannot distinguish the more delicate imperfections. Sit more erect and far enough away from the negative to allow of your working comfortably. The eyes should be about 18 inches from the negative, (b) There may be too much light entering at the sides of your desk and falling upon the face of the negative. All light should come through the opening in the desk and practically all excluded from the sides or back.
Proper Light. No direct light should strike the film side of the negative. The light must be transmitted through the negative by the opening in the desk. An opaque cloth may be thrown over the top of the desk and head. This will assist in excluding all direct light and permit of your seeing the imperfections more easily; also, your eyes will not become tired, as they might if any light were reflected from the surface of the negative. All light for retouching should come through the opening in the retouching desk.
 
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