174 W. Crookes on the Wax-paper Photographic Process. 



cause a stain. Should this happen, either dry it with, blotting 

 paper, or immerse the sheet entirely in the liquid. 



50. If the paper has been exposed to a moderate light, the 

 picture will begin to appear within five minutes of its being laid 

 on the solution, and will be finished in a few hours. It may 

 however sometimes be requisite, if the light has been feeble, to 

 prolong the development for a day or more. If the dish be per- 

 fectly clean, the developing solution will remain active for the 

 whole of this time, and when used only for a few hours, will be 

 quite clear and colorless, or with the faintest tinge of brown ; a 

 darker appearance indicates the presence of dirt. The progress 

 of the development may be watched, by gently raising one cor- 

 ner with the platinum spatula, and lifting the sheet up by the 

 fingers. This should not be done too often, as there is always a 

 risk of producing stains on the surface of the picture. I prefer 

 allowing the development to go on, until the black is rather 

 more intense than ultimately required, as it is generally toned 

 down in the fixing bath. 



51. As soon as the picture is judged to be sufficiently intense, 

 it must be removed from the gall o- nitrate, and laid on a dish of 

 water, (not necessarily distilled). In this state it may remain 

 until the final operation of fixing, which need not be performed 

 immediately, if inconvenient. After being washed once or twice, 

 and dried between clean blotting paper, the picture will remain 

 unharmed for weeks, if kept in a dark place. 



52. The fixing bath is composed of a saturated solution of hy- 

 posulphite of soda diluted with its own bulk of water. Into this 

 the sheets are to be completely immersed, until the whole of the 

 yellow iodid of silver has been dissolved out. This operation 

 need not be performed by yellow light ; daylight is much bettter 

 for shewing whether the picture be entirely fixed. This will 

 take from a quarter of an hour to two hours, according to the 

 time the bath has been in use. 



It will be well not to put too many sheets into the bath at once, 

 in order to avoid the necessity of turning them over to allow the 

 liquid to penetrate every part. 



When fixed, the sheet if held up between the light and the 

 eye, will present a pure transparent appearance in the white 

 parts. 



The fixing bath gradually becomes less and less active by use, 

 and then its action is very energetic on the dark parts of the 

 picture, attacking and dissolving them equally with the un- 

 changed iodid. When this is the case it should be put on one 

 side, (not thrown away,) and a fresh bath made. 



53. After removal from the fixing bath, the sheets must be 

 well washed. In this operation, the effect depends more upon 

 the quantity of water used, than upon the duration of the immer- 



