PHOTOGRAPHIC CORRESPONDENCE.
Mr. Townsend's Wax-paper Process.—At the last meeting of the Photographic Society a paper was read by Mr. Townsend, giving the results of a series of experiments instituted by him in reference to the wax-paper process. One of the great objections hitherto made to this process has been its slowness, as compared with the original calotype process, and its various modifications; and another, that its preparation involved some complexity of manipulation. Mr. Townsend has simplified the process materially, having found that the use of the fluoride and cyanide of potassium, as directed by Le Gray, in no way adds to the efficiency of the process, either in accelerating or otherwise. The iodide and bromide of potassium with free iodine give a paper which produces rapid, sure, and clean results. He discards whey, sugar of milk, grape sugar, &c., hitherto deemed essential, but which his experience shows to be unnecessary. He exhibited three negatives of the same view taken consecutively at eight o'clock in the morning, with the respective exposures of thirty seconds, two and a half minutes, and ten minutes, each of which was good and perfect. The formula he adopts is:
| Iodide of potassium | 600 | grs. |
| Bromide of potassium, from | 150 to 250 | " |
| Re-sublimed iodine | 6 | " |
| Distilled water | 40 | oz. |
The waxed papers are wholly immersed in this solution, and left to soak at least two hours, and are then hung to dry in the usual way. The papers are made sensitive by wholly immersing them in aceto-nitrate of silver of the following proportions:
| Nitrate of silver | 30 | grs. |
| Acetic acid | 30 | minims. |
| Distilled water | 1 | oz. |
The papers remaining in this solution not less than eight minutes. They are washed in two waters for eight minutes each, and then blotted off in the ordinary manner. Mr. Townsend states that there is no need to fear leaving the paper in the sensitive bath too long. He has left it in the bath fourteen hours without any injury. The paper thus prepared will keep ten or twelve days; it may be longer, but his experience does not extend beyond that time. With paper thus prepared a portrait was exhibited, taken in fifty-five seconds, in a room with a side light; but it must be added, that in this instance the paper was not washed, but was blotted off immediately on its leaving the sensitive bath, though not used until two hours had elapsed. Mr. Townsend uses for developing a saturated solution of gallic acid with a drachm of aceto-nitrate to every four ounces of it, but he considers that this proportion of aceto-nitrate may be beneficially lessened. He finds that by this process he is certain of success, and is never troubled with that browning over of the paper which so often attends the use of the other methods of preparation. Besides the rapidity of action which he states, there is the farther advantage that a lengthened exposure is not injurious. The proportion of bromide may vary from 150 grs. to 250 grs.; less than 150 is not sufficient to produce a maximum of rapidity, whilst more than 250 adds nothing to the effect.
Photographic Litigation.—Will you allow me, through the medium of "N. & Q.," to suggest to those who
take an interest in the collodion process, the desirableness of making a subscription to aid Mr. Henderson in his defence against the proceedings commenced by Mr. Talbot, to restrain him (and through him, no doubt, all others) from taking collodion portraits.[[11]]
It does not appear just that one person should bear the whole expense of a defence in which so many are interested; and I have no doubt that if a subscription be set on foot, many photographers will willingly contribute. A subscription, besides its material aid to Mr. Henderson, would also serve to show that public opinion is opposed to such absurd and unjust attempts at monopoly.
It is difficult to imagine how a claim can be established to a right in an invention made many years subsequent to the date of the patent under which the claim is made—not only made by another person, but differing so widely in principle from the patent process. The advertisement in the Athenæum of Saturday last (June 10) shows plainly that it is intended, if possible, to prevent the production of portraits on collodion by any person not licensed by Mr. Talbot; and the harshness of this proceeding, after the process has been in public use for several years, needs no comment.
H. C. Sands.
30. Spring Gardens, Bradford.
Footnote 11:[(return)]
The words of the advertisement are "making and selling."
[We insert this communication, because we believe it gives expression to a sentiment shared by many. Subscriptions in favour of M. La Roche, whose case stands first for trial, are received by Messrs. Horne and Thornthwaite. Our correspondent does not, however, accurately represent the caution issued by Mr. F. Talbot's solicitors, which is against "making and selling" photographic portraits by the collodion process. When giving up his patent to the public, Mr. Fox Talbot reserved "in the hands of his own licensees the application of the invention to the taking photographic portraits for sale," and we have always regretted that Mr. F. Talbot should have made such reservation, founded, as it is, upon a very questionable right.—Ed. "N. & Q.">[