Journal : Photographic notes, vol. 1.
London : Bland and Long, 1856.
Description : pages 157-158.
Subject : Photography — Chemistry (of).
Dear Sir.—In the London Photographic Journal of last month an article was published from my pen, on the Dry Collodion Process. Since that period I have much modified it, having reduced it I may say to a certainty. The following are the advantages I claim for my process :—
1st.—My plates are more easily prepared than by any other process.
2nd.—They are dry, hard, and horny, and may be laid in contact when taken to the field.
3rd.—They will keep before and after exposure for an indefinite period.
4th.—They can be developed with gallic acid in the same manner as Albumen.
5th.—They require no soaking or preparation prior to development.
6th.—They are as sensitive as any of the moist preservative processes.
Having set forth the advantages, I will, with your permission, proceed to make your readers acquainted with the modus operandi.
Coat the plate with Collodion, and then excite in a neutral 30 gr : solution of nitrate of silver. Wash the plate thoroughly under a tap of common water till all free nitrate of silver is got rid of; then immerse in the following bath for 5 or 10 minutes, according to the character of the Collodion,
Nelson's patent Gelatine 64 grs.
Distilled water........14 oz.
Absolute Alcohol.....2 "
Till lately I used 8 grs : of gelatine to the ounce, but I find 4 grs : better.
After it has remained in the above bath the proper time, rear it up to dry on blotting paper in a dark clean room or large box. When dry, the plates should be put away carefully till required. By having several flat dishes to contain the solution of gelatine, many plates may be prepared in an hour.
I develop in a gutta percha dish.*
The saturated solution of gallic acid, to every ounce of which 45 minims of the exciting solution have been added, is placed in the lower half of the dish, and the exposed plate in the raised half. The position of the dish is then reversed, and the liquid flows evenly over the plate without stopping. I find that if the developing agent is poured on the plate from a measure, or bottle, it is very apt to stain. My gutta percha dishes are made to fit the plates, so that no more solution is required than just enough to cover them. In regard to the development, the plates may be divided into two classes, one of which develops rapidly and the other slowly. This difference is dependent upon the Collodion and the state of the nitrate bath. A firm, compact, contractive Collodion develops much slower than a porous pappy film. Superabundance of ether, or the presence of chloroform in a Collodion, makes it more dense and contractive. Acids in the nitrate bath have a similar effect. Hence for plates to develop quickly, a larger proportion than usual of alcohol should enter into the Collodion, and the exciting bath should be neutral. On the other hand the more contractive Collodions always give the most delicate definition in the details; therefore I think it will be preferable to adopt them and put up with the slowness of the development, which will sometimes occupy 4 or 5 hours. All good Collodions, either positive or negative, will be suitable for my process ; but some require a longer time than others in the gelatine bath.
All photographers will rejoice with me that the days of tents, bottles and baths are numbered, and that we can really make a pleasure of our viewing excursions instead of a filthy, pestiferous, fag and toil. I carry with me on an excursion, a camera, stand, and a flat plate-box, with a yellow bag having sleeves ; this bag I fasten to the camera back, and it is at once a chamber to change plates in. I have nothing to do but select the finest positions and expose my plates. On my return I transfer my plates from the box to the developing dishes, cover them up, and go down to supper, with a good digestion and an appetite not a little sharpened by the consciousness that after the withdrawal of the cloth I shall be able to regale my friends with a reproduction, in miniature, of the delicious scenery my own eyes have feasted on during the day.
I am dear Sir,
Hill Norris, M.D.
46, Stafford Street,
Birmingham, Augt. 9th.
* The developing dishes used by Dr. Norris require a few words of description, as we have not given a wood cut. A sheet of gutta pcrcha, twice the size of the plate, with allowance for a half inch margin to be turned up all round, is bent in the middle, so us to form as it were two dishes, making an obtuse angle with one another. The gallic acid is poured into the horizontal half of the dish, and the plate is placed, face upwards, in the other half. By tilting the dish the gallic acid flows evenly over the plate.