Feb. 5. 1853.] 



NOTES AND QUERIES. 



141 



or more, and then into water : this is merely to 

 fix it for the after process at your leisure. 



To clean the Negative. — Get a zinc tray about 

 three or four inches deep, with another tray to 

 fit in at the top, about one inch deep ; fill the 

 lower tray with boiling water, so that the upper 

 tray may touch the water ; put your solution of 

 hyposulphite of soda, not strong, in the upper 

 tray, and then your negatives one by one, watch- 

 ing them with care until the iodine is removed; 

 then put them in hot water, containing a small 

 piece of common soda (the size of a nutmeg to 

 about two quarts of water), for about ten minutes ; 

 pour off the dirty water, and then add more hot 

 water, shaking them gently for a short time ; pour 

 off' the water again, and then add fresh hot water, 

 and let it remain until it is cold, after which take 

 them out cabefui.I-y one by one, and put them in 

 clean cold water for an hour or two ; then take 

 them all out together, and hold up to drain for 

 a short time, and tlien put them between three or 

 four thicknesses of linen, and press as much of the 

 water out as you can ; then carefully {Jor now all 

 the size is removed) lay them out flat upon linen 

 to dry. 



Mode of Waxing the Negatives. — Melt the 

 pure white wax over a lamp of moderate heat, 

 just merely to keep it in a liquid state ; then fill 

 the same deep tray as above described with boiling 

 water, and with another similar to the upper one 

 before described (which must he kept for this 

 purpose only) ; put a clean piece of blotting-paper 

 in this tray, and lay your negative _/ac<? dowmcards, 

 and with a soft flat hog's hair-brush, about an inch 

 wide, dip it into the liquid wax, and brush the 

 negative over, when it will be immediately trans- 

 parent, and it can be done so that there is very 

 little redundant wax, after which it may be put 

 between two or three thicknesses of blotting-paper 

 and ironed, if necessary, which, however, should 

 not be very hot, when it is ready to take positives 

 from. 



Positives on Negative Paper. — Take one part 

 of the iodide of silver before described, and add 

 two parts of water ; then add as much iodide of 

 potassium as will redissolve it. Brush your paper 

 with the foregoing, let dry, put into water, and 

 proceed, in all respects, as above described for the 

 negatives. 



Excite for Positives. — Excite with No. 1. : 

 blot oif : lay it in your press, place the negative 

 face downwards: expose to the light from ten 

 seconds to iialf a minute, or more, according to the 

 light (7iot in the sun), and bring out with No. 3. ; 

 and when it is nearly developed add No. 1.; then 

 take it up and pour water upon it, and then place 

 it in hyposulphite of soda (cold) until the iodine 

 is removed ; after which put it into allum water, 

 about half a teaspoonful of powdered allum in two 

 quarts of water ; this will readily remove the hy- 



posulphite, and also fix the positive more parti- 

 cularly ; it will also take away any impurities 

 which there may be in the paper, after which put 

 It into clean cold water, and change two or three 

 times. 



I have been thus particular in describing the 

 process which I have adopted, more especially for 

 beginners ; and with great cleanliness and care in 

 each process, and especially in keeping all the 

 bottles with the chemicals free from dirt of every 

 kind, the foregoing will lead to favourable results. 



W. J. Newton. 



I have been making some experiments in pre- 

 paring the iodized paper in the following maimer, 

 more especially in consideration of the present 

 price of iodide of potassium : — 60 grains of nitrate 

 of silver ; 60 ditto of iodide of potassium, cleaned 

 and prepared as before described, by the addition 

 of three ounces of water, — that is 3 oz. altogether ; 

 60 grains of cyanide of potassium ; add a little of 

 this at a time, and shake it up ; and I generally 

 find that this quantity is sufficient to redissolve 

 the 60 grains of iodide of silver. Brush the paper 

 over with the above, and when the wet surface dis- 

 appears, dip it into cold water containing one 

 drachm of dilute sulphuric acid to one quart of 

 water; and then into water for half an hour, 

 changing the water once : pin up to dry. I have 

 not had an opportunity of trying this for negatives, 

 but I have taken some good positives with the 

 paper so prepared. 



N.B. — I find that if the paper is allowed to dry 

 with the cyanide of potassium, or that it is allowed 

 to remain in the dilute sulphuric acid water too 

 long, it weakens the paper so mucli as to be very 

 absorbent. I would therefore wish to know fi-om 

 any of your correspondents whether this arises 

 from taking away the size, or Injuring the fibres 

 of the paper ? and, if so, whether a paper prepared 

 with starch, instead of size, would be better ? as it 

 appears to me that this mode of Iodizing might be 

 an improvement. At all events. It is an enormous 

 saving of Iodide of potassium ; as, for instance, to 

 redissolve the 60 grains, it would take 1^ oz. of 

 iodide of potassium (about four shillings) ; whereas 

 60 grains of cyanide would not cost more than one 

 penny or twopence. W. J. N. 



Collodion Film on Copper Plates. — Would any 

 of your correspondents kindly describe the manner 

 In which the collodion film may be transferred to 

 prepared copper plates ? 



It was noticed by your correspondent H. W. D. 

 In Vol, vi., p. 470. J. M. S. 



Treatment of the Paper Positive after fixing. — 

 1. Is It absolutely necessary for the preservation 

 of the picture, that the size should be wholly re- 

 moved from the paper ? It seems to me that the 

 hot- water treatment materially injures the tone.. 



