The Optical Magic Lantern Journal (February 1898)

The Optical Magic Lantern Journal and Photographic Enlarger. 29 than some other kinds of developing agents, and therefore, to my thinking, is not quite so suitable for portrait and landscape work; tbe development requires carrying somewhat farther than with either of the first-named developers, as owing to the freedom of the image from any trace of yellowness, its resistance to light is less ; therefore, requires more apparent density to make up for it. Metol is a substance possessing qualities in which hydrokinone is deficient, giving abundance of detail in the weakly-lighted portions of the subject, but lacking somewhat in density, unless the image is rather under-exposed, when a fair amount of printing power is easily acquired, but at the loss of its specially good quality of evolving detail from the shadows. If, however, it is combined with half the quantity of hydrokinone and carbonate of soda used as the alkali we gain the good qualities of each substance without any drawbacks so far as I am aware, each supplying the shortcomings of the other. With correct exposure this combination is hard to improve upon, but in case of unknown exposures, especially over-exposures, it is not quite so easy to get a first quality negative by tentative development. Reduction and subsequent intensification will have to be resorted to if there is much over-exposure—an under-exposed plate is more amenable to treatment, a long continued action of the much diluted developer will get out as much, or more, detail ais is possible to be evolved by any developer; the proportions of the constituents of the solution remaining unaltered, the addition of water being all that is required. This developer in a concentrated form makes very dense images ; in fact, unprintably so, but when used of a suitable strength the density and detail come out together in a very harmonious manner. Rodinal and eikonogen are much the same in working qualities, their density-giving power depending much on the strength of their solutions, and are useful for developing images impressed by weak light and rapid exposures. Rodinal is a developer supplied as a liquid preparation requiring nothing but the addition of water; for use, it is therefore a convenient form for travellers, a small bottle taking up little room and giving a minimum of trouble in mixing for use. Hikonogen is sold as a brownish coloured powder, eventually becoming quite black if air is allowed to have access to it and losing its powers of development; still, when fresh, it is a favourite with some workers and gives good modelling, although the images are inclined to thinness; the colour of the image is rather warmer than that produced with hydrokinone, Glycin is one of the more recently introduced chemicals for development and is highly esteemed by some workers. Nearly all these developing agents have an alkaline reaction and some will develop an image without the addition of other alkali; therefore, acids such as used for the preservation of solutions of pyrogallol are unsuitable. With the exception of hydrokinone the alkali used renders the developing agent much more soluble in cold water as without it, although by heating it may be dissolved, on cooling it will be a great part again precipitated. Sulphite of soda is an absolutely necessary addition to this class of developer, for without it an almost immediate discolouration takes place. The solubility of these preparations by different makers vary somewhat, and also the colour of the solutions, although their action is nearly the same. Tables as Lantern Stands. By F. J. ® EBS TE OW far it is proper to trust to luck ‘ia! Svan SCRIMGEOUR. in lanternism depends upon the idea of the lanternist. The travelling operator has, as a rule, more to do with Dame Fortune than he ee cares; aod often sincerely wishes he YY? could tip her well beforehand. But to that she will not stoop, and centre gas brackets, monstre chandeliers, and distorted structural deformities have to be fought and conquered as they appear. How often do we have to guess the size of the hall to which we are going, and pack up our 12 feet screen in hopes that it will be neither too large or too small? And how often do we arrive to find that an 18 feet sheet would have been more in keeping with the capacity of the hall? Well, I suppose almost as often as we find ourselves at a hall in size adapted to a tenfooter ! At present there are two methods possible, either of which may be used to eliminate the element of chance. The first is, to proceed thither sometime previous to the date of exhibition and make a personal examination; the second consists partly of a note to the hallkeeper or some other responsible party requesting measurements, and partly of the figures, etc., received in answer to the request. The first method is very satisfactory if convenient (which