produced by the collodion process, but that there was a limit beyond which progress could not be made. The great range of subjects in still and animate life requiring very rapid exposures, were practically out of the power of collodion, to compass satisfactory results. At this time, when there seemed to be a very constant and increasingly urgent demand for more rapid acting lenses and for "lightning processes," there appeared the wonderful argentic bromide Gelatine Emulsion, which, in four short years, has superseded the collodion process almost, if not altogether, and besides (notwithstanding the opposition of the elite of the profession, whom for a time it p8 leveled with the rest of the workers, but who were quick to see and acknowledge the extraordinary merits of the new candidate) it has caused such a quickening of the pulses of the business, and such an increase in its range and adaptability as never before was known, and which, in the year or two past, has caused such an activity in invention and in other ways, as to make that period of time so remarkable for the many new things that have been brought out, and the many new processes that have been adopted, as to render a detailed account of such for the profession, and also for the amateur, most desirable.

It is with such a view that this book is offered to the photographic public, and that numerous and still increasing army of amateurs, who have taken up photography as an amusement, to while away a leisure hour.

For to these latter a few hours' study of a good hand-book is about all that is necessary to enable them to expose and develop a dry plate, a little practice only being requisite to the successful performance of the same.

There may be many, however, who, having made a promising commencement, would like to proceed farther and acquire a knowledge of former photographic processes, as well as those which succeed the making of the negative, such as printing, toning, fixing, etc., and in fact, learn how to make a finished photograph.

To such, particularly, and to all photographers, this book is offered, in full confidence that it will be a useful companion in the studio and in the field.

To accomplish this end we will take the reader as an apprentice, and commencing at the beginning, instruct him in that knowledge he would have to acquire were he an actual apprentice in a photographic studio, p9 working the wet collodion process, after which an equally full course of instruction will follow for the dry plate and other new processes, both for negative making and for printing.

In the following pages, also, will be found many useful formulæ that have been carefully culled from a mass of published contributions, from many of the leading spirits in photography, most of which have been verified practically by the author, and others bear on their faces so plainly the impression of their practicability as to need no assurance that they are reliable.

In getting up this work I have availed myself of information from any and all sources at my command, giving credit where possible, and endeavoring to make everything clearly understandable, and neglecting no details necessary to the successful working of every formula, even by the youngest learner. p10

GLASS.

QUALITY OF GLASS SUITABLE FOR PHOTOGRAPHIC PURPOSES AND HOW TO PREPARE IT.

Mr. Hardwick, than whom there can be no more faithful or competent guide, says that much care should be taken in the selection of glass to be used in the production of photographic negatives.

Window glass is always unsuitable, because of its inferior quality, having scratches upon its surface and air bubbles in its substance, each of which causes irregularities, as well in the negatives as in the subsequent printing; also the squares are seldom flat so that they do not lie true in the holder, and hence a part of the image may be out of focus; and also they are extremely liable to be broken by compression in the printing frames.

Formerly many photographers used a thin plate glass of very fine quality, but of late years the great demand for glass suitable for such purposes has made it possible for the manufacturers to prepare a cheaper quality, well adapted to the uses of photography.

TO PREPARE THE GLASS FOR USE.

Before proceeding to wash the glass, each square should have its edges roughened, by means of a file or a coarse stone, or the edges of two pieces of glass may be abraded against each other in such a manner as to remove the sharpness, which is so liable to injure the fingers in the various manipulations.

In the process of cleaning the glass it is not sufficient p11 to wash it with water. Other means are necessary to remove grease, rust and dirt, which would not yield to the influence of water alone, and for this purpose a solution of caustic potash is most generally used.

The glass is immersed in the potash solution, each piece separately, and when the dish is full, it should be left not longer than is necessary for the potash to have its proper action, for when left for a considerable time the solution of potash (if strong) will attack the surface of the glass, to its injury.

When a suitable time has elapsed (which in the case of new glass should not be more than one day or night, and in the case of old negatives not longer than to cause the film to slip off), the glass should be removed and washed with water, after which it should be immersed in the same manner, in a solution composed of four parts of water to one of commercial nitric or sulphuric acid, or the two mixed, as may be the most convenient.

This latter solution removes rust or other metallic blemishes, that have not been affected by the potash, and also effectively neutralizes all traces of the potash that have remained on the surfaces of the glass.

The glass may be permitted to remain in the acid an indefinite time, as it can have no injurious effect on it, as might the potash, and when required for use, it should be carefully washed and immediately albumenized and set up in racks to dry.

ALBUMENIZING THE GLASS.

While the glass is still wet from the washing, after being taken from the acid, it should be coated with a preparation of albumen, prepared as follows: p12

To the albumen or white of a fresh egg, add eight ounces of water; put it in a bowl and thoroughly beat it with an egg beater, or in any manner that may be convenient, until the fibre or structure is completely destroyed, when it should be filtered through loose cotton, and after the addition of a few drops of strong ammonia, it is ready for use.

Many prefer to beat up the albumen before adding the water, in which case it should be beaten into a stiff froth, when the proper amount of water is added, and after the froth has subsided the whole is filtered and the ammonia put in last.

The albumen being prepared and the glass ready, a square is taken in the left hand, and clean water flowed over it, until no particle of dust can be seen adhering to either surface, when a small portion of the albumen is flowed on it, and after covering every part of the surface the excess is allowed to drain off the right hand lower corner, after which, if running water is at hand, the back of the same portion of the plate should be passed under the faucet, and the water will carry off any excess of albumen which might return or crawl, as it is termed, up the back of the plate from the point where it is drained.

The greatest care should be taken to avoid dust settling on the plate during the coating and afterwards while drying, and after the glass has been