Dry plate (photography)

“ Gelatine plates for photo-micrography. The requisites of a perfect plate are, great sensitiveness, combined with extreme latitude in time of exposure, and density in development. It should be of a fine texture, showing clearly the most delicate lines and markings, p235 evenly coated and free from spots or blemishes of any sort. [2]
[2] The Stanley dry plate has all these qualities in the highest perfection.
It is most provoking to have an otherwise perfect negative marred or ruined by opaque or transparent spots appearing in its most important portions. ”

“ One who has experienced the wonderful sensation of working in a faint yellow-ruby light and by the application of certain mysterious chemicals of seeing a picture gradually come into view on the creamy surface of a dry plate will never again be satisfied to push the button and allow some one else “to do the rest.” However, if you do not wish to go into photography extensively you may at least learn just what limits your hand camera has, and at the end of the season in place of a lot of ill-timed pictures you can have an album full of creditable prints for which no apology will be necessary. ”

“ Cut film can be dried with speed only if placed in a draft of warm air. Drying boxes, with a chute or chimney and with fans to drive the air through from an alcohol stove, will dry several dozen films in an hour. The films must not be closer together than about one inch, which makes the drying boxes rather cumbersome.
Marking Negatives.—After development and drying, and before filing or printing, each plate should be marked with data for purposes of future identification. ”

“ Anthony's transparency plates. Gelatino albumen plates. Porcelain and opal plates for lamp shades, etc., etc. FORMULA FOR DEVELOPING DRY PLATE TRANSPARENCIES.
When making transparencies by contact use artificial light, either gas or a common lamp. A deep printing frame is the most suitable, having a piece of thin plate glass in it to support the negative. Lay the negative down with the film side up, place upon it the dry plate, put in the back and press firmly down with the springs; expose to gas light from six to ten seconds at a distance of twelve to fourteen inches ”

“ To begin with, the real photographer will use plates instead of films, as much better pictures usually are possible by their use. Dry plates come a dozen in a box, usually packed face to face—that is, with the film or sensitive sides facing. The plate-holder must be loaded in a dark room or dark closet, with absolutely no exposure to daylight or any artificial light whatever except a very faint light from a dark-room lantern, a combination of ruby and yellow glass or paper. We should always test our dark room and light by means of a plate before we trust them to actual working conditions. ”

“ When open landscapes are being taken, during summer time, medium rapid plates generally will be quick enough, but many opportunities, for pictorial work, arise under conditions of atmosphere and light, in which to obtain fully exposed negatives with a shutter, demands a plate of extreme sensitiveness, and if for no other reason than that they offer this opportunity of carrying a varied assortment of plates, many workers prefer dark slides, to any form of magazine. ”

“ So soon as the film is dry, which will be seen by the iridescent aspect it assumes, the plate is allowed to cool to the ordinary temperature, and is then at once exposed either beneath a positive, or beneath an original drawing the lines of which have been drawn in opaque ink, so as to completely prevent the luminous rays from passing through them; the light should only penetrate through the white or transparent ground of the drawing. ”

“ With the wet-collodion process, usually the method employed by large photomechanical printers, this method can be used because it is a simple matter to carefully examine the glass plate to be employed, but it will be obvious that with the ordinary dry plate all the imperfections of the glass, such as dirt, scratches, air-bubbles, etc., will be clearly reproduced in the image. ”

“ How to Develop a Dry Plate. —Next take your camera into your dark-room and develop the plate, that is, immerse it in a chemical solution called a developer to bring the picture out on it. To do this you must get a tray and put the exposed dry-plate in it, film side up, and pour the developer over it.
Fig. 56c. the pin-hole camera complete with cloth and rubber band
Rock the tray after you have poured the developer over the plate to keep the solution flowing forth and back evenly over it all the time. ”

“ A quick plate does not15 suffer in the same way, however small the stop may be. It has already been stated that isochromatic plates may be employed with a hand camera. For ice and snow views there is not much to commend their employment, unless to give a deeper shade to the sky and to the vast crevasses which so often form part of the foreground. The darker sky allows faint clouds to be visible in a print when they otherwise would be absent. ”

“ No general rules can be laid down; the appearance of the properly developed image depends on the thickness of the film, the granularity of the silver salt, the presence or absence of silver iodide, and the composition of the emulsion used. Experience only is of value, and the best way to secure uniformly satisfactory results, is to keep as far as possible to one brand of plates. With some plates, for example, very little of the image should appear at the back of the plate, with others the greater part of the image must be distinctly visible there. ”

“ We are only talking of the ordinary landscape when the effect of storms is not desired. It is not within the scope of this work to show how a landscape and a sky negative may be printed into one plate to form a transparency from which a new negative may be made; suffice it to say that, by using collodio-chloride, or by the use of a slow dry plate and exposing to candle light, the former may be produced in almost the same way that the print is produced, and a negative may then be produced in the camera or by a dry plate. ”

“ A trained eye can recognize the proper degree of dryness from the sheen, which varies with different kinds of ink, but on the whole is always duller when the design is dry than while it still is wet. It is highly necessary that the design be thoroughly dry. It is possible to keep a designed plate for years without etching it, so long as it is protected against injury. ”

“ It is not at all necessary to know the process of making a sensitive plate, but it is quite necessary to know something of the action of light on the plate in order to make a good picture. A photographic negative is formed by the chemical action of light admitted through a lens or even a tiny hole, into an otherwise light tight box, and striking a glass plate, film, paper, or celluloid, coated with sensitive silver salts. The part of the light that affects this coating is the blue rays. ”

“ For this reason a quick plate with a moderate gradation is to be preferred—as being most generally useful—but it should be a plate which is absolutely free from fog, and it should also be of as fine a grain as possible, the size of which has something to do with development. This is still more true when a camera stand and hand exposures are made. With a slow plate with feebler intensities of light, which must be the case when the lens is stopped down to admit of hand exposures, the gradation becomes more steep than if a fairly bright light be employed. ”

“ On the other hand, I have worked in a closet two feet deep, by the dim light of a single ruby lamp. But in photography as in everything else the "golden mean" is preferable.
If kept in a perfectly dark box, the dry plates need not be developed for months. Travellers often change plates, and even develop and fix them, at night, in their rooms, by the aid of a ruby lantern. As the changing of plates is an operation which consumes but little time, this may be done with safety, but we would recommend the young photographer to make use of his dark room for the process of developing. ”

“ The greater the extent to which the light acts, the smaller will be the amount of moisture the coating of the plate will absorb when exposed to a damp atmosphere. If the surface of the plate be now dusted over with a fine powder, as drop black, or graphite, the greater the amount of moisture certain parts of the film have absorbed, the greater will be the amount of colour such parts will retain, and so exactly reproduce the light and shade of the original negative. ”

“ Care must be taken not to touch the film side of the plate during development or fixing, as the gelatine coating becomes very soft and will show the slightest scratch or abrasion. We must dry the plate away from dust, sunlight, or artificial heat. ”

“ By the aid of photography it is easy to prepare a plate, transparent where the zones of odd order fall, and opaque where those of even order fall. Such a plate has the power of a condensing lens, and gives an illumination out of all proportion to what could be obtained without it. An even greater effect (fourfold) can be attained by providing that the stoppage of the light from the alternate zones is replaced by a phase-reversal without loss of amplitude. ”

“ As I have before said, the artist should be careful to see that the interior of the camera is clean and free from dust, as the small particles flying about, or set in motion by the sliding of the holder into the box, attach themselves to the plate, and cause the little black spots, by which an otherwise good picture is frequently spoiled. Care should also be taken in withdrawing the dark slide, in front of the plate, from the holder, as the same effect may be produced by a too hasty movement. The lens is the last thing to be uncovered, by withdrawing the cap c. ”

“ The exact temperature at which to dry these films cannot be arbitrarily stated, as so much will depend upon the picture which is to be printed; therefore, a few experiments will be necessary before settling down to an exact form of working. A good plan that answers admirably is to raise the water in the tank of the drying oven to boiling point before coating the plate, then coat the plate, lay it on the slab, let the water in the tank boil for a few minutes then turn out the gas and let the plate dry. ”

“ Then he would put the plate in and watch the heat (some now have a thermometer) and he would just pick it up every once in a while to see how it is developing. That process gave to him the first picture, the daguerreotype, and those are to-day the handsomest pictures ever made by photography. I have two or three of them which are partly spoiled, but to-day they far surpass anything we have ever since done in the science of photography. After the mercury process, it was very easy to wash the plate off. ”

“ In the latter case, a plate of medium rapidity is generally employed, such an exposure given, as makes no serious strain on the developer used to bring the latent image fully out; the action of light having been ample, and the plate not so easily spoiled, as one of higher sensitiveness, there is not that call for such skilful treatment, as where light action on a highly delicate emulsion, has been but brief, and needs to receive careful handling, before good, well-graded negatives may be produced. ”

“ In connection with what has already been considered in relation to the reproduction of drawings, it may be well to refer to the making of plates from photographs. The selection of a good photograph is of the first importance. It should be brilliant, and with all the contrast of light and shade and as much detail as possible, for something is always lost in both these respects in the process of reproduction. A good plate can be made from a good photograph, but cannot from a bad one. ”

“ Zinc plates are also employed as provisory supports instead of glass, opal or porcelain plates. The modus operandi is exactly the same.30 The plates should be well planed, free from scratches, etc., and well polished to obtain glossy pictures without one having recourse to a film of collodion. For matt pictures, i.e., without gloss whatever, the plate should be finely granulated, and when waxing a very light pressure should be exerted to remove the excess of wax, else it might be quite impossible to strip off the picture in transferring on paper. ”

“ As a matter of fact all things being taken into consideration the larger the plate up to 12 × 10 or 15 × 12 employed the more rapidly will the worker progress.
Large plates, especially in architectural work, tend to make the operator more careful and conscientious when out with the camera; and even more so when in the developing room. So much more can be done with a large plate than with a small one; the use of a large plate moreover checks the common failing so prevalent among amateurs of rushing work and recklessly using plates. ”

“ Then you put a dry plate, which is a piece of glass with chemicals on it, in the camera, and then you take it out and put it in some more chemicals, the right name of which is a developer, and then you see a picture on the dry plate, only it is right side up, and not like the one on the ground-glass door.
It's the best fun in the world taking pictures; and I can't see that it improves your mind a bit—at least not enough to worry you. You have to practise a great deal before you can take a picture, and everybody who knows anything about it tells you to do something different. ”