By A. GOODALL.

[Footnote: Read before the Dundee and East of Scotland Photographic Association.]

The process of making gelatino bromide of silver prints or enlargements on paper or opal has been before the public for two or three years now, and cannot be called new; but still it is neither so well known nor understood as such a facile and easy process deserves to be, and I may just say here that after a pretty extensive experience in the working of it I believe there is no other enlarging process capable of giving better results than can be got by this process when properly understood and wrought, as the results that can be got by it are certainly equal to those obtainable by any other method, while the ease and rapidity with which enlarged pictures can be made by it place it decidedly ahead of any other method. I propose to show you how I make a gelatino bromide enlargement on opal.

[Mr. Goodall then proceeded to make an enlargement on a 12 by 10 opal, using a sciopticon burning paraffin; after an exposure for two and a-half minutes the developer was applied, and a brilliant opal was the result.]

We now come to the paper process, and most effective enlargements can be made by it also; indeed, as a basis for coloring, nothing could well be better. Artists all over the country have told me that after a few trials they prefer it to anything else, while excellent and effective plain enlargements are easily made by it if only carefully handled. A very good enlargement is made by vignetting the picture, as I have just done, with the opal, and then squeezing it down on a clean glass, and afterward framing it with another glass in front, when it will have the appearance almost equal to an opal. To make sure of the picture adhering to the glass, however, and at the same time to give greater brilliancy, it is better to flow the glass with a 10 or 15 grain solution of clear gelatine before squeezing it down. The one fault or shortcoming of the plain argentic paper is the dullness of the surface when dry, and this certainly makes it unsuitable for small work, such as the rapid production of cartes or proofs from negatives wanted in a hurry; the tone of an argentic print is also spoken of sometimes as being objectionable; but my impression is, that it is not so much the tone as the want of brilliancy that is the fault there, and if once the public were accustomed to the tones of argentine paper, they might possibly like them twice as well as the purples and browns with which they are familiar, provided they had the depth and gloss of a silver print; and some time ago, acting on a suggestion made by the editor of the Photographic News, I set about trying to produce this result by enameling the paper with a barium emulsion previous to coating it with the gelatinous bromide of silver.

My experiments were successful, and we now prepare an enamel argentic paper on which the prints stand out with brilliancy equal to those on albumenized paper. I here show you specimens of boudoirs and panels--pictures enlarged from C.D.V.--negatives on this enamel argentic.

[Mr. Goodall then passed round several enlargements from landscape and portrait negatives, which it would have been difficult to distinguish from prints on double albumenized paper.]

I have already spoken of the great ease and facility with which an argentic enlargement may be made as compared with a collodion transfer, for instance; but there is another and more important point to be considered between the two, and that is, their durability and permanence. Now with regard to a collodion transfer, unless most particular care be taken in the washing of it (and those who have made them will well know what a delicate, not to say difficult, job it is to get them thoroughly freed from the hypo, and at the same time preserve the film intact), there is no permanence in a collodion transfer, and that practically in nine cases out of ten they have the elements of decay in them from the first day of their existence. I know, at least in Glasgow, where an enormous business has been done within the last few years by certain firms in the club picture trade (the club picture being a collodion transfer tinted in oil or varnish colors), there are literally thousands of pictures for which thirty shillings or more has been paid, and of which the bare frame is all that remains at the present day; the gilt of the frames has vanished, and the picture in disgust, perhaps, has followed it.

In short, I believe a collodion transfer cannot be made even comparatively permanent, unless an amount of care be taken in the making of it which is neither compatible nor consistent with the popular price and extensive output. How now stands the case with an argentic enlargement? Of course it may be said that there is scarcely time yet to make a fair comparison--that the argentic enlargements are still only on their trial.

I will give you my own experience. I mentioned at the outset that seven or eight years ago I had tried Kennet's pellicle and failed, but got one or two results which I retained as curiosities till only a month or two ago; but up to that time I cannot say they had faded in the least, and I have here a specimen made three years ago, which I have purposely subjected to very severe treatment. It has been exposed without any protection to the light and damp and all the other noxious influences of a Glasgow atmosphere, and although certainly tarnished, I think you will find that it has not faded; the whites are dirty, but the blacks have lost nothing of their original strength. I here show you the picture referred to, a 12 by 10 enlargement on artist's canvas, and may here state, in short, that my whole experience of argentic enlargements leads me to the conclusion that, setting aside every other quality, they are the most permanent pictures that have ever been produced. Chromotypes and other carbon pictures have been called permanent, but their permanence depends upon the nature of the pigment employed, and associated with the chromated gelatine in which they are produced, most of pigments used, and all of the prettiest ones, being unable to withstand the bleaching action of the light for more than a few weeks.

Carbon pictures are therefore only permanent according to the degree in which the coloring matter employed is capable of resisting the decolorizing action of light. But there is no pigment in an argentic print, nothing but the silver reduced by the developer after the action of light; and that has been shown by, I think, Captain Abney, to be of a very stable and not easily decomposed nature; while if the pictures are passed through a solution of alum after washing and fixing, the gelatine also is so acted upon as to be rendered in a great degree impervious to the action of damp, and the pictures are then somewhat similar to carbon pictures without carbon.

I may now say a few words on the defects and failures sometimes met with in working this process; and first in regard to the yellowing of the whites. I hear frequent complaints of this want of purity in the whites, especially in vignetted enlargements, and I believe that this almost always arises from one or other of the two following causes:

First. An excess of the ferrous salt in the ferrous oxalate developer; and when this is the case, the yellow compound salt is more in suspension than solution, and in the course of development it is deposited upon, and at the same time formed in, the gelatinous film.

The proportions of saturated solution of oxalate to saturated solution of iron, to form the oxalate of iron developer, that has been recommended by the highest and almost only scientific authority on the subject--Dr. Eder--are from 4 to 6 parts of potassic oxalate to 1 part of ferrous sulphate.

Now while these proportions may be the best for the development of a negative, they are not, according to my experience, the best for gelatine bromide positive enlargements; I find, indeed, that potassic oxalate should not have more than one-eighth of the ferrous sulphate solution added to it, otherwise it will not hold in proper solution for any length of time the compound salt formed when the two are mixed.

The other cause is the fixing bath. This, for opals and vignetted enlargements especially, should always be fresh and pretty strong, so that the picture will clear rapidly before any deposit has time to take place, as it will be observed that very shortly after even one iron developed print has been fixed in it a deposit of some kind begins to take place, so that although it may be used a number of times for fixing prints that are meant to be colored afterward it is best to take a small quantity of fresh hypo for every enlargement meant to be finished in black and white. The proportions I use are 8 ounces to the pint of water. Almost the only other complaints I now hear are traceable to over-exposure or lack of intelligent cleanliness in the handling of the paper. The operator, after having been dabbling for some time in hypo, or pyro, or silver solution, gives his hands a wipe on the focusing cloth, and straightway sets about making an enlargement, ending up by blessing the manufacturer who sent him paper full of black stains and smears.

Argentic paper is capable of yielding excellent enlargements, but it must be intelligently exposed, intelligently developed, and cleanly and carefully handled.