LOW-POWER WORK 



37 



plates. This ended, remove the plate and flow over it a developer consisting of equal 

 parts of the hydroquinone and soda solution, which happens to suit the emulsion 

 admirably. 



In a few seconds the positive will commence to appear, growing in density and 

 definition with exceeding rapidity. Attaining sufficient definition and blackness, the 

 developer is poured back again into the measure (for it can be used over and over 

 again, as when using it for Nikko paper), and the slide allowed to drain for two to four 

 seconds, when it will be found to grow distinctly foggy. Wash quickly and sharply — 

 not losing much time, as development is apt to go on notwithstanding the washing — 

 and plunge into the hypo bath, which is of the same strength as that employed for 

 fixing negatives. 



In a few minutes — a much shorter time than that required for fixing negatives — 

 the positive image will appear quite free from yellowness. Let it rest in the bath for 

 a few minutes longer than appears actually necessary, just the same, only for a 

 shorter time, as was recommended when dealing with negatives. If now the back- 

 ground appears perfectly transparent and the image bright and black, the operator 

 may be satisfied, but if brown it has been over-exposed. Try half the former 

 exposure. If, on the contrary, it is everywhere faint and shows lack of detail — the 

 hair points hardly out and the edges of the suctorial tubes deficient in continuity — the 

 time before the gas has been too short — remedy: double it. 



But should the slide appear with a muddy ground, so very common and so very 

 unsightly, one of three faults have caused it. Either the negative is too thin- 

 remedy, intensify it in a manner to be yet explained — or the slide has been over- 

 exposed or over-developed. To ascertain which of the three, first look at the 

 negative. If too thin the gas-flame will be too easily seen through it. If the fault 

 is over-exposure of the slide, try less ; and if over-developed, do not be so slow over 

 the process. Suppose, after trying again, the background of the slide still appears 

 dirty-looking and overcast, then glance at the original specimen and note if the 

 mounting medium is clear or yellow. If yellow, there is no remedy but taking a 

 fresh negative with more exposure. But here we may be confronted with a most 

 troublesome difficulty. Suppose a more exposed negative is taken and we find on 

 development that the background is sufficiently dense and black so as to produce a 

 clear, clean positive, but at the same time the proboscis itself is much over-exposed, 

 all its details being choked up with deposit. Thinning will be of no service because 

 we shall thin the background at the same time as the proboscis, and the final result 

 will be the same as if the whole negative had been exposed for a less time. We are 



