(From Humphrey's Journal, No. 17, Vol. 8.)
On the Use of Alcohol for Sensitizing Paper.
TO SENSITIZE PAPER.
I have practised for some time the following simple method, which appears to me to be very superior for cleanliness and celerity in working, for depth of tone, and especially for purity of white in its results. By means of it T have produced very satisfactory results upon paper which was otherwise nearly worthless.
To your sensitizing solution (which should be not less than 60 grains to the ounce), whether simple nitrate or ammonio-nitrate, add 50 per cent, of alcohol. Float the paper upon the solution for 40 seconds.
This method answers equally well for albumenized or plain paper. You will find that the solution penetrates the paper which flattens instantaneously upon it. It becomes as transparent as though it were oiled, and every minute air-bubble or defect in the paper is rendered visible. Remove the air-bubbles by pressing upon the paper about an inch from the bubble, and thus driving it out under the paper. In doing this, if the solution flows partially over the back of the paper, shake it until the paper is wholly immersed, which will prevent any unevenness in printing. The paper reassumes its transparency in the toning bath, but it will dry a pure white. The sensitising solution will not become materially discolored even after frequent applications of albumenized paper. Should it become so much discolored as to give a dark hue to the paper, shake it in a bottle with two drachms Of animal charcoal and leave it a night to settle. It will filter clear. A very small portion of your solution may be made available in sensitizing a sheet of paper by pouring it upon a clean glass, the size of the paper or a little larger, which is carefully levelled and nicely laying down the paper upon it. This is useful when your solution is too small to float in your trays. The alcohol causes it to flow and be absorbed with perfect evenness.
To remove the papers from the solution and dry them:—Provide a dozen or more clothes-pins, of the kind that are supplied with a ring of india-rubber for a spring. Into the top drive a pin firmly and bend it to a hook. Lift a corner of the paper by passing under it the point of a quill tooth-pick, and attach to it one of the clothes-pins; lift the edge out by this, and attach another to the other corner. You may thus carry the sheet by the pins and hang it upon a line to dry without touching it with the fingers, a matter of some importance to Amateurs of the art, who must have unstained hands for their day's business.
It may be worth while here to add the following simple and economical method of printing, which I have found to surpass in convenience and afford all the advantages of the most expensive printing frames. Four common clothes-pins, such as work with a wire spring supply pressure enough for a 4/4-plate. Lay your prepared paper upon the negative, and next to it about twenty separate leaves of thin common wrapping paper cut to the size of the negative; next a sheet of tolerably stiff and smooth writing paper, and lastly, a piece of glass as a back to the whole. Let the glass back be pushed from the lower edge of the papers about 1/20 of an inch, or just so far as to enable you to pinch the negative and papers with the thumb-nail and forefinger. Attach a pin to each corner and your negative is prepared for exposure. Now, to examine your picture without endangering its displacement:—remove the pins from one end, and place it, face downwards, on a table, the other end with pins attached projecting an inch beyond the edge. Hold down the back glass with the left hand, while with the right you remove the pins and pinch the papers and negative together between the forefinger and thumb-nail. Upon the smooth sheet of paper you can easily slide the back glass an inch from the edge. Hold it there, and on the uncovered margin attach three of the pins with as deep a bite as they will take. You may now examine your picture to within an inch of its margin, as you would turn over the leaves of a book. To replace the back, lay it again on the table and slide the back glass up to the pins before you remove them. The rest of the process is obvious.
The minutiæ of my communication may excite a smile with some, but I shall always act upon the principle, that nothing is more out of place than an apology for minuteness in describing manipulations.