THE PHOTOGRAPHIC NEWS. Dec. 10, 1858, p.164
Q. What is the chief advantage gained by the employment of waxed paper in photographic operations?
A. The chief advantage of the waxed paper is, that it will keep well in hot weather. It has been urged as an objection to the paper process that the paper will not keep a sufficient time after excitation to answer the purpose of travellers, who are compelled to carry about with them a portable tent, and all the necessary apparatus for manipulation. Such difficulties are immediately overcome by the use of the waxed paper process.
Q. Are there not a variety of methods employed by photographers in the application of the waxed paper process?
A. There are several different plans all founded on the mine principles, as in most other branches of photography.
Q. Describe another process from that which has already been stated; what is the first thing to be done?
A. In proceeding to detail another process the first operation is to wax the paper on a sheet of heated iron, and to be careful that the coating of wax is even and regular.
Q. What is the second?
A. The second part of the operation is to immerse the waxed paper in a bath of iodide of potassium.
Q. How long should the paper be immersed?
A. From half-an-hour to two hours.
Q. How is the solution to be composed?
A. To a quantity of boiled whey is added iodide of potassium, 4 drachms; bromide of potassium, 60 grains; sugar of milk, 5 drachms. When the paper is removed from the bath, it is dried between two sheets of blotting paper.
Q. What is the third operation?
A. Sensitising in a bath of aceto-nitrate of silver, composed of nitrate of silver, crystallised acetic acid, and pure water. The paper so floated in the bath for one or two minutes, washed in distilled water, dried between flat surfaces, and exposed in the camera.
Q. What is the fourth operation?
A. That of the development of the negative proof, which is done by immersing it in a solution of gallic acid; after which it is washed several times in pure water.
Q. What is the fifth operation?
A. Fixing the proof. This is accomplished by immersing it in a solution of hyposulphite of soda, washing it again in pure water, and then drying it by the fire.
Q. What is the process adopted by M. Geoffroy?
A. In his experiments on the waxed paper process M. Geoffroy hit upon a new and more expeditious mode of conducting the operation; it is called the ceroleine process.
Q. How is the operation conducted?
A. In the first place M. Geoffroy places five hundred grammes (about eighteen ounces) of yellow or white wax in one litre (about a quart) of alcohol of commercial strength in a glass retort, and boils the alcohol until the wax is completely dissolved; having previously attached a receiver to the retort to collect all the products of the distillation, he then pours the still fluid mixture into a glass vessel, and as it cools, the myricine and cerine solidify, while the ceroleine remains in the alcoholic solution; this liquid is separated by straining it through fine linen; and by a final operation it is filtered through paper in a glass funnel. This mixture, kept in a stoppered bottle, may be used when required.
Q. How does M. Geoffroy continue his process?
A. He dissolves five drachms of iodide of ammonium (or potassium) in five ounces of alcohol, together with fifteen grains of fluoride of potassium or ammonium. Taking a capsule he pours drop by drop upon fifteen grains of iodide of silver as much of a solution of cyanide of potassium as is required to dissolve it. This dissolved iodide of silver he proceeds to mix with the former solution, shaking it briskly. There remains at the bottom of the bottle a thick deposit of all the above salts, which serve to saturate the alcohol with which that already saturated is successively replaced.'
Q. Having prepared these solutions, how does M. Geoffroy proceed?
A. These two bottles being ready, when about to prepare negatives he takes about six ounces of solution No. 1, of ceroleine and alcohol, and mixes it with five drachms of solution No. 2. Filtering the mixture with care so as to avoid crystals, which spot the paper, he makes a bath in a porcelain dish in which he immerses the paper five or six pieces at a time, continuing to do so until the solution is exhausted. After being taken, out, suspended on a hook, and dried, these papers, which are of a very uniform rosy tint, are covered up from dust and kept dry. They are sensitised by nitrate of silver. The development of the image by gallic acid, and the fixing the proof by the application of hyposulphite of soda, are accomplished by the ordinary method, generally following that of LeGrey, to which M. Geoffroy adds fifteen or thirty grains of camphorated spirits of wine to one quart of a solution of gallic acid.
Q. What are the peculiar advantages of the plan adopted by M. Geoffroy?
A. Time process according to the formula of M. LeGrey is slow and tedious when compared with that of Geoffroy; and very great care is necessary both in the selection and application of the materials. By Geoffroy's plan the iodising and waxing of the paper are effected in one simple and rapid operation; the absorption is, as may be supposed, very uniform and complete, from the facility with which alcohol penetrates, and that granular appearance which is so objectionable in ordinary waxed processes is avoided, owing to the properties of the ceroleine.
Q.. Is the solution of ceroleine in alcohol easily made?
A. It is, and at a cheap rate; and the residue of stearine and myricine may be employed with success for waxing fixed proofs.
Q. Are negative pictures taken by this process equal in every respect to those taken by the process of LeGrey?
. For the transparency of the proofs, the intensity of the blacks, or the clearness of the whites and half-tints, they are equal if not superior to those taken by any other process.
(To be continued.)