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.
Non-Halation Plate. In photographing interiors the strongest highlights, such as the windows and other out-of-door openings, are almost always very dense and blurred at the edges. This is due to halation, or reflection from the inner surface of the glass. Our Non-halation plate is double coated, under coat a 23, the surface a 26x. Consequently, though it has the speed of a 26x, the blur of halation is lost in the brilliant 23 emulsion next to the glass surface. This means that in poorly lighted interiors an exposure sufficient to get detail in the shadows will not endanger the highlights. Snappy detail in the highlights under most trying conditions is the characteristic performance of this plate. It is especially serviceable in photographing machinery where bright parts and troublesome reflections are unavoidable. We most strongly recommend it for all landscapes, seascapes, white draperies, wedding gowns and other subjects where it is necessary to bring wide contrasts of light and shade into harmony. We also offer it to the amateur as a most economical plate for general use, on account of its remarkable latitude.
694. The normal developer used with ordinary plates should be diluted with an equal volume of water. This allows the developer to penetrate to the lower film before development has made much progress in the upper film. Both films should develop simultaneously. Development in the diluted developer will be much slower, but the results will show.
695. Since the Non-halation is double coated it is almost impossible to judge its density by the developing light as in ordinary practice. It is therefore conservient to determine the completion of the development by using the factor system. Development with pyro (diluted), will be completed in about fourteen times the time in which the highlight appears. The speed of the Non-halation plate may be reckoned the same as the 26x. It should be noted, however, that only in very full timing can the whole advantage of the great latitude and wonderful gradation of this plate be brought out.
Orthochromatic Plates. One of the signs of the times is the increasing demand for orthochromatic plates in all classes of work. These are undoubtedly the plates of the future. They will do all that an ordinary plate of the same general character will do, and in many cases much more. Therefore we have been ever ready to meet the demand of the trade for orthochromatic plates of special character for special work. For general all-around work, where the highest color sensitiveness is demanded, the Ortho and the Non-halation Ortho; for commercial work and the reproduction of furniture samples, where increased contrasts are demanded, the C Ortho. With a little care in handling, any of our orthochromatic plates may be developed without trace of fog in a ruby light safe for ordinary plates.
Ortho. It is well known that yellow and green values are the life of the picture in many a landscape. In ordinary photographs these bright patches of color are shown as black or very dark. About 90 per cent, of landscape photographs neither give all that the eye sees, nor show the proper relation in what they do give. For instance, it will be found quite impossible to secure with one exposure on an ordinary plate, printable detail in a foreground of green foliage as well as in the light clouds on the horizon. When the Ortho plate is used this is easily obtained. It is impossible on an ordinary plate to get values in autumn scenery. The brilliant coloring of the foliage is much more dull, black and lifeless than it should be. With an Ortho plate the picture tones up wonderfully.
698. The improvement made by the use of an orthochromatic plate will be noticeable. But with a filter difficult problems become easy, and true and exact rendition of color value is obtained. For this purpose we make two filters, a light one for general landscape work and a deep one for work where more exact rendition is necessary as in the reproduction of paintings. These filters are specially adjusted for use with our Ortho and Non-halation Ortho plates and should not be used with any other plates.
699. We strongly commend our Ortho plate to microscopic workers. Because of its high sensitiveness to yellow light the exposure, in cases where the subjects are in yellow stain, will be very much reduced. Subjects in blue stains cannot be photographed successfully on an ordinary plate, but with an Ortho this is possible. A light yellow screen will be useful in obstinate cases.
700. For general all-around work, as well as work in which the highest color sensitiveness is demanded, the Ortho is supreme among single coated plates. It has a most pleasing gradation, vigor, roundness, and fullness, without that harshness which so often characterizes a plate of great color sensitiveness, and which tends to the production of pictures in which chalk and soot effects prevail. Speed is the same as our 26x.
Non-Halation Ortho. Many advanced workers use but one kind of plate for all their work. There is much to be said for this system. It is a very rational way of working. To these we especially commend the Non-halation Ortho plate, for it has all the qualities of our regular Non-halation, and all the color sensitiveness of our Ortho. The speed is the same as our 26x, and the latitude the same as the regular Non-halation. It is unquestionably the best plate made in adaptability to every special need in difficult or varied work.