The wet-plate photographer sighed for such a process as would give him plates which might be kept for a length of time before exposure, and between exposure and development, so that he would not have to carry with him a chemical laboratory and workshop ; and he sighed for a process which would enable him to shorten his exposures.
The first requirement was in a certain degree supplied by " dry-collodion " processes. In these, as indicated by the name, the plates were used dry. They could be kept for some time both before and after exposure. They had serious drawbacks, however. The results were gen erally inferior in quality to those got by the use of wet plates, and the exposure required was longer. Besides this, most of the plates required in their preparation the use of the troublesome collodion and bath.
A few years ago a great change took place. A pro cess was invented which appears to embody everything which the photographer could possibly desire. This is the gelatine dry-plate process. The history of this process we cannot give here, but may say that the names which are most intimately connected with its discovery are those of Dr. R. L. Maddox and Mr. Charles Bennet.
In this process the plates are dry. They may be kept for an indefinite time either before they are exposed or between the time of exposure and development ; how long is not known, but certainly the limit of time is to he measured by years. The exposure is less than one tenth of that which was required for wet plates. The manipulations are so easy that they can be performed by any one almost without practice, and may be so cleanly that the most scrupulous need no longer fear to take up the practice of what used in the wet-plate days to be sarcastically entitled the " black art." If we add to all this that the results are artistically superior to those ob tained by wet plates, and that, whereas everything which could be clone with a wet plate can also be done with a dry, many things which were impossible with a wet plate are no longer so when a gelatine one is used, we will see that the stride made was immense.
What has, however, perhaps done more than anything else to make the benefit of the change fully available to the photographic public is that plates by the new pro cess have become an article of commerce.
It is evident that a wet plate, which has to be made and finished within an hour or two, must be made by the operator himself. The collodion dry plates, it is true, would keep for some time, but the time was com paratively limited and was somewhat uncertain. The consequence was that, although these plates were pro duced commercially by one or two firms, they were never largely used. Besides this, the price was so high as to prevent the greater number of photographers from adopting them had there been no other objections.
The amateur, as a consequence, if he used dry plates, manufactured them himself at the cost of great labour, considerable expense, and frequently with disappointing results.
It is true that there are even now in the days of gela tine plates a few amateurs who manufacture their own plates, but those are such as have an experimental turn and take pleasure in the work itself. They will gener ally be found willing enough to admit that neither economy nor better results arise from their labours.
The Britannia plates have now been before the public for some years and have given uniformly satisfactory results. They appear to possess every good quality which is to be found in a photographic plate. At the present stage, before we have commenced our actual instructions for working plates, we cannot enter into technicalities which would probably not be understood by most of our readers, but may briefly say that the plates are such that negatives of the best quality may be produced by their means with the utmost certainty, the shortest possible exposure, and the minimum of trouble, whilst the price is most moderate.