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.
Overcoming Halation. The cause of halation is fully explained in this lesson. The use of non-halation plates will aid in overcoming this difficulty. A good plan is to over-expose and then develop according to instructions given in lesson on "Special Development," in Volume II.
Obtaining Detail In The Shadows. This you can only hope to obtain by giving full exposure. (Of course the angle of the source of light must be directed towards the shadows). If a plate is under-exposed, treat it as such in the development. This will aid in the production of detail. Another excellent plan is to breathe on the shadow portions of the plate during development. The warm breath will cause the developer to act more readily. Another method is to lay the fingers on the shadow portions, for a few moments at a time, during development. The warmth from the hand will aid the developer to act in producing detail. Usually, however, it is difficult to overcome lack of detail in shadows in any other way than by giving full exposure.
Plate Developing Contrasty. Due to under-exposure. The shadows have not been sufficiently exposed to give softness. Always bear in mind, that the stronger the high-lights the more deep and dense are the shadows; therefore, time sufficiently to overcome this contrast, using diluted developer - thus softness will be produced.
Plate Fogging During Development. If the camera is pointed directly into the window, toward the source of light, the illumination will be likely to reflect into the lens and cause fog. Non-halation plates will partially overcome this, but never photograph an interior, or any other object, with the light facing the instrument. On the contrary, locate the camera so that the light will fall upon the object being photographed, making the picture from the high-light side, so that no shadows will appear in the foreground. Over-exposure may also fog the plate, if the overexposure is excessive. The image will flash up in the developer under such circumstances. If old developer is at hand, place the plate in it at once. If you have no old developer, add from 10 to 20 drops of Bromide to the normal bath, and conclude the development. Carry the plate a little farther than required for good printing, and after fixing reduce with Red Prussiate of Potash. It is advisable to add two drops of Bromide to the developer for all interiors. This will prevent fog and permit of long development.
Thin Negatives, Full Of Detail But With No Printing Quality, When Using Non-Halation Plates. This simply indicates under-development. Non-halation plates will fix out more than the ordinary plate. It is also advisable to develop them in diluted developer requiring a longer time for development. Therefore, develop them considerably further. It is much better to overdevelop and reduce, if necessary (according to instructions given in lesson on Reducing), than to under-develop.