Bayswater.
Developing Paper Pictures with Pyrogallic Acid (Vol. vii., p. 117.).—Your correspondent R. J. F. asks if any of your photographic correspondents have developed their paper negatives with pyrogallic acid. I have long been in the habit of doing so by the following process. Of Mr. Archer's developing solution, viz.,
| Pyrogallic acid | 3 grs. |
| Acetic acid | 1 drachm. |
| Distilled water | 1 oz. |
take twenty grs. (minims): add an equal quantity of distilled water, and five drops (minims) of acetic acid. I pour the mixture upon a glass plate, and put the sensitive surface of any picture upon it; moving, it up and down by one corner, to prevent the paper being stained, and to observe the development of the picture; which, when sufficiently come out, I blot and wash immediately, and fix with hyposulphite of soda or bromide of potassium.
Thomas Wyatt.
Manchester.
Photography in the Open Air; Improved Camera.—In your Number 172, p. 163., there is a Note of mine in reference to the use to which thin sheet India rubber might be applied. I there alluded to the difficulties attending a single "portable camera," in which all the coating, developing, &c. of your plates is to be done; and for those gentlemen who have the means of carrying about with them a second box, I have devised a modification of Archer's camera, which I think, will prove very useful. It is one which I am about to make for myself. This second box is one in which, when travelling, I can pack my camera, frames, glasses, and chemicals. Having arranged your camera, you proceed to arrange the second box, or "laboratory." This laboratory has three short legs, which screw, or fasten by any simple contrivance, to it, so that it may stand a sufficient height from the ground to allow the bath, which fits in like the one in Archer's camera, to hang beneath it, and also that when working you may do so with ease. It is lighted by either yellow glass or India rubber. There are sleeves of India rubber for your arms, and the holes in the sides of the box traverse nearly the whole of the sides, for the purpose of moving your hands freely from one end of the box to the other; there is also an opening for the head. The bottom of the box is divided: about two-thirds of it, and the nearest to you, has a gutta percha tray, with the four sides, three inches high, fitting it quite tight; and in one corner a tube a few inches long, also of gutta percha, fixed to it, and passing through the bottom of the box, to allow the refuse washings to run off. In the middle of this tray a developing stand of gutta percha is fixed to the bottom, on which to lay the glass plates. The other one-third of the bottom of the laboratory is fitted thus:—There is a slit across the box, immediately before the wall of the tray, for the nitrate of silver bath to slip in. Immediately beyond the edge of the bath is a small fillet of wood running across the box parallel with the bath, and so placed that if the bottom of the dark frame to contain the glass plate is rested against it, and the top of the frame rested against the end of the laboratory, the frame will slope at about an angle of forty-five degrees. Let there be a button, or similar contrivance, on the underside of the lid of the box, that the lid of the dark frame may be fastened to it when open. Bottles of collodion, developing fluid, hypo-soda, or solution of salt, &c., may be arranged in various convenient ways within reach. The proceeding then is very easy. Place the bath-frame and bottles in their places; rear the glass plate in the frame; shut the laboratory lid; place your hands in the sleeves and your head in the hood; fix the door of dark frame to the top; coat the plate; place it in the bath with collodion side from you (it will then be in convenient position when you draw it out of bath to place at once in the frame); fasten the frame door; open the box lid; remove to camera; after taking picture, return frame to its place in camera; bring the plate to developing stand; develop; pour solution of salt over; remove from box; finish outside with hyposulphite of soda.
I have been thus explicit to render the matter as plain and intelligible as possible without aid of diagrams. But I shall be happy to give any
one any further information, either privately, or through "N. & Q." It seems to me that by this contrivance you simplify the process as much as is almost possible; you keep separate the different processes, and run little or no risk of mixing your chemicals, a misfortune which would spoil several hours' work, as well as entail a considerable loss of materials. The box would be no expensive article; any one possessing a little mechanical skill could construct it for himself, and its use as a packing-case for your apparatus would repay the cost.
I have for some time been using a developing fluid, which appears to have some desirable qualifications for it is simple, inexpensive, and keeps good, as far as I have tried it, for a very long period. I have worked with it when it has been made ten weeks; it slightly changes colour, but it throws down no deposit, and does not ever stain the film; when first made, it is colourless as water. Dr. Diamond has kindly undertaken to test its value, and if he pronounces it worthy of being made known, the readers of "N. & Q." shall shortly have the benefit of it.