id="HOW_TO_COAT_PLATES"/>HOW TO COAT PLATES.

The ferro-plate is held between the thumb and first two fingers of the left hand. The collodion bottle is held in the right hand, and the collodion is poured on the right upper end of the plate, flowed to the left upper corner, by deflecting the plate in that direction, and then down the left side toward the hand, and the excess run back into the bottle from the right lower corner, when it has all run off, the plate should be gradually brought to a perpendicular position and rocked from right to left, that is, perpendicular to the end, p18 then to the side, until the film has set or become fixed, which may be ascertained by touching the film at the lower corner of the plate, when, if it breaks and does not run farther, it has set and should, without delay, be immersed in the silver solution, where it should remain until it has become fully sensitized, which will be in from 2 to 5 minutes.

The plate should be lowered into the bath by one continuous motion; any stoppage will cause a line and spoil the plate.

The plate is sensitized when on removing it from the bath it presents a smooth, yellowish surface; if it shows lines as of water running off a greasy surface, it is not coated; return it to the bath.

EXPOSURE OF THE PLATE.

The plate having become sufficiently coated is taken from the bath, well drained, and placed in the holder or shield, and a piece of glass of the same size put behind it, which is to receive the pressure of the spring on the door of the holder, and force the plate into its proper position evenly, so that all parts will be in focus.

The holder containing the plate is then taken to the studio, or light room, where the subject, we will say, has already been posed; the camera set and focused, the exposure is then made, after which it is returned to the dark room for development.

DEVELOPER AND DEVELOPMENT.

In the preparation of a developing solution for plate pictures, we must consider that we desire to produce a picture, which, to be admired, must have p19 pure whites, clear shadows, be full of detail and have an easy gradation of light and shade.

That you may succeed in this object, use the following formula, and persist until you have learned its every modification:

DEVELOPER.

The four ounces of iron should be dissolved in the sixty-four ounces (fluid) of water, and the acetic acid and tannic alcohol added.

In using this solution, develop your plate over a large filter, which will receive all your surplus developing solution, and conduct it into a bottle for use again; drain the plate into this filter before washing, wash carefully and then place it into the fixing solution—the developing solution which has filtered through into the bottle is afterwards used in the proportion of one-half of old to one-half of the new or fresh solution. This greatly improves the high lights of the picture, and by using more or less of the old solution, effects can be produced that are impossible by any other means.

Great care should be taken to cause the developing solution to flow evenly and with one sweep, as it were, over the whole surface, so that the action may be as near as possible equal on all parts of the surface.

In a very few seconds after the action of the developer has commenced the picture will show up. The plate meanwhile should be kept in motion and the p20 solution caused to flow from side to side and from one end to the other, in order that the development may progress evenly and with the same speed on all parts.

The picture will gradually grow and brighten, until all the detail that might be expected is seen in the shadows; then pour off the remaining solution into the filter and proceed to wash the plate until all traces of greasiness disappear; when the plate is sufficiently washed and is ready to be fixed or cleared. Another developing solution is prepared as follows:

Make a 64-ounce saturated solution of protosulphate of iron, into which drop tannin solution enough to cause a precipitate, which remains undissolved after shaking, then add drop by drop pure nitric acid, until the precipitate is taken up and the solution becomes clear. To one ounce of this add water, until it tests 18 to 20 grains to the ounce by the hydrometer, then add one ounce acetic acid, which perfects the formula and constitutes the developer.

FIXING SOLUTION.

The solvent most generally used for fixing or clearing positives is cyanide of potassium.

By the term "fixing" is meant the dissolving from the collodion film all the iodide of silver not acted on by the developer; the remaining portion of the silver is in a metallic state and constitutes the image; the cyanide very readily dissolves the iodide, but acts very slowly on the metallic silver.

This fixing solution should be contained in a glass upright dish, enclosed in a wood case, with a tight or close-fitting cover, this in order that as little exposure to the air as possible may be had, as the fumes p21 arising from the evaporation of the solution are injurious.

Two ounces of cyanide to 64 ounces of water will make a suitable fixing solution for plate pictures; if, however, its action is thought to be too slow, add more.

The plate picture having now been developed and fixed, it only remains that it should be dried, varnished, cut into shape, placed in the proper envelopes and it is ready for delivery.

Those desiring more extended instructions in the making of plate pictures are referred to the work on that subject, entitled, "The Ferrotype and How to Make it," published by E. & H. T. Anthony & Co., of New York.

ARGENTIC DRY PLATES FOR POSITIVES.

The Phenix Plate Co., the largest manufacturers of ferrotype plates in this country, and whose name is familiar with every ferrotypist, as well as most photographers, have lately placed on the market ferrotype plates, with surfaces coated or sensitized with gelatine emulsion, which they, offer as a substitute for the ordinary collodion positive or tintype.

The plates are cut to sizes and packed in much the same manner as the Stanley or any other dry plates are, and being extremely sensitive to light, they must be handled with the same care.

The manufacturers claim, that "the 'Argentic Dry Plate' will be found far superior to any other form of positive plate, giving as it does the maximum of beautiful effects with a minimum of labor, producing a rich and brilliant picture with a rapidity and cleanliness never before attained, doing away as they do p22 with the use of the silver bath and all its concomitant evils, pinholes, stains, fog, etc., not forgetting the vast saving in time and temper. The argentic plate is always ready-at-hand, and the working of it is simplicity itself. Their permanency and reliability is beyond question. These plates are extremely rapid. An exposure of from 1 to 3 seconds will suffice with a good light, 2 minutes to develop, 3 to fix, wash, dry and varnish, and the operation is complete, ready within ten minutes for delivery. For out-door views these plates work well with a drop shutter exposure, and the results, both for portrait and view work, are remarkable for fullness of detail, and