PRINTING WITH READY SENSITISED PAPER.
This is to be brought about by printing, a process whereby the shades of the negative are reversed, and a positive is obtained as has been already explained.
There are many printing processes, but there is one which has held its own against all competition, and which, in spite of the prophecies which were ventured when first rival processes took the field, is still the popular process of the day. This is what is known as "silver printing," or to be more precise, printing on albu menised paper, rendered sensitive with chloride of silver.
It is useless to disguise the fact that this process has certain drawbacks, or rather has one very great drawback. The results cannot be relied on as permanent. Silver prints of thirty years' standing are to be met with as fresh as they were on the day when they were done, but they are the exception rather than the rule. Fading of some sort generally sets in after some ten or fifteen years. To be placed against this, there is the incom parable beauty of the results. There is something in a silver print which cannot be imitated by means of any other process ; and, whatever may he said as to the inad visability of issuing prints which are not permanent, the fact remains the same that the silver-printing process continues the favourite one both with professionals and amateurs, and bids fair to do so for many a long day. For this reason we describe it here.' Most professional photographers purchase what is known as salted albumenised paper. This is paper coated with albumen containing a certain quantity of chloride in it—either chloride of sodium (common salt) or some other chloride, or a mixture of several. This is sensitised, as will be afterwards described, the nitrate of silver which is used decomposing the chloride in the albumen and forming chloride of silver.
Until recent years the amateur as well as the pro fessional could follow no other course than this one, which was troublesome, and involved the very great inconvenience of having to prepare paper, print on it, and finish it all within a few hours,—twenty-four at the most,—because the paper once prepared would not keep, but turned brown by exposure to the air, even in a dark room.
Some twenty years ago a paper was invented which will keep for months without turning in colour. This is now a regular article of commerce. It is called "ready sensitised paper," and the convenience of it is enormous, especially to amateurs who have very often to print, tone, etc., at such odd hours as they can spare from other duties. Indeed we can only compare the difference be tween an amateur working ordinary paper—sensitising it as he requires it, and finishing his prints immediately afterwards—and one purchasing ready sensitised paper— printing at what times he can, and possibly finishing his prints at the end of the week or even the month—to the worker with wet plates and that with dry.
The writer has worked both ready sensitised paper and has sensitised paper himself, and he is of the opinion that, with such sensitised paper as is sold by Marion and Co. at the present day, better results can be got than by sensitising paper as it is required.
The necessary appliances for printing with ready sensitised paper are— (1) One or more printing frames.
(2) Three porcelain flat dishes, somewhat larger than the largest print to be manipulated.
(3) Some ready sensitised paper.
The chemicals required are— (1) A tube containing fifteen grains of chloride of gold.
(2) An ounce or two of eitheracetate of soda or of borax.
(3) Hyposulphite of soda (already mentioned as the chemical used for fixing dry plates).
A printing frame is a frame for holding the negative, having a back hinged. in two pieces, which is pressed against the negative by two springs. One spring bears against each half of the hinged back, and it is thus possible to open away from the negative either half of the back. It will be seen that if the negative be placed in the frame, if a piece of paper be laid upon it, and if the back be laid on this paper and he pressed into ,it by the springs, then the paper will be kept in close contact with the negative, whilst at the same time, by easing one spring at a time, and by opening one-half of the back, one-half of the print can be viewed without danger of shifting the relative positions of the print mid the negative.