Turner's paper, of the "Chafford Mills" make, is greatly to be preferred, and therefore I will presume that to be used, and of a medium thickness. The great fault of Turner's paper consists in the frequent occurrence of spots, depending upon minute portions of brass coming from the machinery, or from the rims of buttons left in the rags when being reduced to pulp, and thus a single button chopped up will contaminate a large portion of paper; occasionally these particles are so large that they reduce the silver solutions to the metallic state, which is formed on the paper; at other times they are so minute as to simply decompose the solution, and white spots are left, much injuring the effect of the picture.
Whatman's paper is much more free from blemishes, but it is not so fine and compact in its texture; the skies in particular exhibiting a minutely speckled appearance, and the whole picture admitting of much less definition.[[3]]
All papers are much improved by age; probably in consequence of a change which the size undergoes by time. It is therefore advisable that the photographer, when he meets with a desirable paper, should lay in a store for use beyond his immediate wants.
It may not be inappropriate to mention here, in reference to the minuteness attainable by paper negatives, that a railway notice of six lines is perfectly legible, and even the erasure for a new secretary's name is discernible in the accompanying specimen, which was obtained with one of Ross's landscape lenses, without any stop whatever being used, and after an exposure of five minutes during a heavy rain. The sky is scarcely so dense as could be desired, which will be fully accounted for by the dull state of the atmosphere during the exposure in the camera.
Having selected your paper as free from blemishes as possible, which is most readily ascertained by holding it up to the light (as the rejected sheets do perfectly well for positives, it is well to reject all those upon which any doubt exists), mark the smoothest surface;—the touch will always indicate this, but it is well at all times not to handle the surfaces of papers more than can be avoided. There is much difference in various individuals in this respect; some will leave a mark upon the slightest touch, whereas others may rub the paper about with perfect impunity.
I prefer paper iodized by the single process; because, independently of the case and economy of time, I think more rapidity of action is attained by paper so treated, as well as that greater intensity of the blacks, so requisite for producing a clear picture in after printing.
To do this, take sixty grains of nitrate of silver and sixty grains of iodide of potassium, dissolve each separately in an ounce of distilled water, mix and stir briskly with a glass rod so as to ensure their perfect mixture; the precipitated iodide of silver will fall to the bottom of the vessel; pour off the fluid, wash once with a little distilled water, then pour upon it four ounces of distilled water, and add 650 grains of iodide of potassium, which should perfectly redissolve the silver and form a clear fluid. Should it not (for chemicals differ occasionally in their purity), then a little more should be very cautiously added until the fluid is perfectly clear.
The marked side of the paper should then be carefully laid upon the surface of this fluid in a proper porcelain or glass dish. Then immediately
remove it, lay it upon its dry side upon a piece of blotting-paper, and stroke it over once or twice with a glass rod; this as effectually expels all the particles of air as complete immersion; it is also more economical, and has the advantage of requiring much less time in the after-immersion in the hypo. when it is required to remove the iodide. Either pin the paper up, or lay it down upon its dry side, and when it becomes tolerably dry (perfect dryness is not requisite), immerse it in common cold water for the space of four hours, changing the water during that time three or four times, so that all the soluble salts may be removed; often move the papers, so that when several sheets are together, one does not press so much upon another that the water does not equally arrive at all the surface.
If this paper is well made, it is of a pale straw colour, or rather primrose, and perfectly free from unevenness of tint. It will keep good for several years; if, however, the soluble salts have not been entirely removed, it attracts damp, and becomes brown and useless or uncertain in its application.