Mr. Shadbolt is certainly mistaken in saying that positives printed from negatives will not stand a saturated solution of hypo. soda, unless they be printed so intensely dark that all traces of a picture by reflected light are obliterated. I have used nothing but a saturated solution for fixing my positives for a considerable time, and my experience agrees with that of other of your correspondents, that the picture is not as much reduced by a saturated solution as by a weaker one. By adding about one grain of sel d'or to every eight ounces of saturated solution, very rich black tones will be obtained.
I inclose a specimen of what I have got in this way.
C. E. F.
[The specimen sent is most satisfactory; we wish that the locality of the view had been stated.—Ed.]
Mounting Positives on Cardboard.—In the absence of any other reply to J. L. S. (Vol. ix., p. 282.), the following, as the method I always adopt, may serve his purpose.
Having cut the positive to the size required, and trimmed the edges, place it upon the cardboard to which it is intended to be attached, and carefully centre it; then with a pencil make a slight dot at each of the angles. Remove the proof, and lay it face downwards upon a piece of clean paper or a cloth, and with any convenient brush smear it evenly over with a paste made of arrowroot, taking care not to have more than just enough to cover it without leaving any patches. Place it gently on the cardboard, holding it for the purpose by two opposite angles, and with a silk handkerchief dab it gently, beginning in the middle, and work any little superfluity of the paste towards the edges, when it will be gradually pressed out. The whole may be placed in a press, or under a pile of books to dry.
My object in using arrowroot is simply that of having a pure starch without colour, and it serves as a size to the paper, which has lost that originally in it by the repeated washings, &c.
The paste is made very thin, thus:—Put a teaspoonful of arrowroot (not heaped) into a teacup with about two spoonfuls of cold water, and mix into a paste: then add boiling water enough to fill the cup, and stir. Many photographers merely attach the edges of their pictures, but I prefer them to adhere all over. Gum is fatal to the beauty of a photograph, unless it is previously re-sized.
Geo. Shadbolt.