The Optical Magic Lantern Journal (April 1891)

The Optical Magio Lantern Journal and Photographio Enlargor. expose the resulting print will be very flat. With this style of negative you should get the right exposure (and not over-exposure) and use a strong developer ; but when enlarging from a good plucky negative you have a good latitude in the exposure and need not fear over-exposure within reason. As a rule, negatives that are fair ones, I say err on the side of over-exposure and correct any mistake when developing. Now comes the question of what developer to employ. Use the iron developer if you want the best results, although you can get fair results with quinone or eikonogen, but certainly the best are got by iron developing. All the various makers of bromide papers send out formule and full instructions with the paper, and it is always best to follow that, as the maker should certainly know what is best for his own papers, and if the instructions sent out are followed all should go right. For those who like to make their own developer I will give the one I use, and they can try it :—, (1) Make a sat. sol. oxalate potash, and make it acid with acetic or hydrochloric acid and number it 1. (2) Make a sat. sol. of iron, and alsomake acid with same acid ; number 2. I use for my iron sotution, the double salts of iron and ammonia as used in the old wet plate days and called the ‘double salts of iron” or ammonia-sulphate of iron, to be bought at any photographic chemist (this is much dearer than the ordinary iron—about four times the cost). There are great advantages in using the double salts of iron over the ordinary iron as sold, as you can develop two or three prints with the same developer and get good results with all, and again you can mix it ready for use and keep it for weeks and it will retain its developing power. I have used it now for some years and still go on doing so. (3) Make a ro per cent. solution of bromide. Then for use take No. 1, 40z.; No. 2, roz.; No. 3, two or three drops. This is a full-strength developer. As a ruleI take half new developer (as just given) and half old (as I keep my developer and do not throw it away) for use, and in another measure have some developer of full strength, in case I require it to bring up the picture and where you are likely to give over-exposure you should adopt this plan. The main points when developing with iron are to keep the oxalic potash and the iron solutions distinctly acid, and to always use an acid bath, viz. :—Water, 3002. ; acetic acid, 14 drams, and give two or three washings in the acid bath after developing and before washing. As to the hypo bath some recommend it to be strong, whilst others weak. I always keep a sat. sol. of hypo, and use one part of this to two parts of water. As to the other developers —viz., quinone and eikonogen—they will both do fairly well, but are not, in my opinion, so good as the iron developer, and so I stick to the iron; but to those who want to try it, I can only say any formula of quinone will answer. I have tried them all, and find little difference between them, although I must say I prefer one that has not got any caustic potash in it ; always use carbonate potash or carbonate soda with your quinone. Eikonogen, I think, works still better than quinone, but hardly up to iron. I use for my etkonogen developer the No. 1 formula as sent out by Marion and Co., viz. :— 103 No. i. Dissolve by boiling Eikonogen tee loz. Jin, say, 100z. of Sulphite of soda .., 30z. ) water, and then make up to 6002. Water... sea vee 6002. Carbonate of Soda (washing soda) 302. Water « 2002. For use, mix three parts of No. 1 with one part No. 2. This works well, but I prefer to add a few drops of. a Io per cent. solution of bromide. I find a very good one solution of eikonogen is the one I am now using for trials. Eikonogen ies 20z.§ Mix as described Sulphite of Soda... 60z. before. Carbonate Soda ... 202. Carbonate Potash 10z. Water ses -900z. This is a strong solution, and will do well for any under exposed prints ; but I, as a rule, dilute it with equal quantities of water for use. One requires a few experiments before he is sure of his results ; but after you are proficient in the use of the developer it works very well and gives a good black tone. In all cases of developing bromide paper I use a drop or so of Io per cent. bromide. 202 Flashes on Lantern Topics, By BULL'S-EYE. IT would seem as if the optical lantern is rising to a renaissance. Hardly a place, small or large, but in its returning season has its course of lectures, and invariably one or more of these is illustrated in the now familiar way. That there should be now and again an occasional accident is only what might be expected. One of these took place recently, and I allude to it to point a moral. A scratch company had taken the Corn Exchange, Kirkaldy, for nothing less than opera, their merits lying more in singing than real acting. The place was fitted up as a theatre—stage, scenery and orchestra, with the inevitable limelight. This was produced by a couple of the usual bags of oxygen and coal gas for hydrogen ; each was weighted with a half-hundredweight (56lb.), and they were put in an out-of theway corner, and the light directed when necessary on the stage and performers by the one operator and director ; but in the middle of the performance there occurred a sudden explosion. All the gas lights were blown out, as well as first the nearest window, then another at the extreme end of the long hall, and almost immediately after another at the stage end opposite. The scenery caught fire, but was soon put out. Several ladies, young and old, fainted, and there was for a time a panic ; but with praiseworthy coolness the gases were relighted, the audience was calmed, and the opera was continued to its close. The oxygen-bag had exploded, it and the pressure boards being found spread out like an opened book. Great carelessness only could have allowed the pressure board to be caught by some obstruction, and this not being noticed—by some means the hydrogen must have been pressed into the oxygen-bag till the explo