218 



NOTES AND QUERIES. 



[No. 174, 



who would most thankfully acknowledge the 

 favour) an amended description of his paper pro- 

 cess, embracing replies to the following Queries : 



1. How strong should the cyanide solution be 

 that is to be added "drop by drop;" and how 

 much of it is likely to redissolve the precipitate 

 formed by the first mixture ? 



2. Should the paper be brushed with, floated 

 on, or immersed in the solution ? If either of the 

 latter, for how long a time ; and what then ? 



3. How is the bath of nitrate of silver prepared, 

 and the mode of applying it to the paper ? 



4. How much sulphuric acid is added to a given 

 quantity of water, in which the paper is placed 

 after removal from the exciting bath; and is it 

 immersed or floated ? 



5. Is the paper, when removed from the water, 

 to be partially dried with blotting-paper, and used 

 in its damp state ? or will it keep, and how long ? 



6. What is the probable time of exposure in the 

 camera ? 



7. How is the picture developed ? and, finally, 

 how fixed? John James. 



Difficulties in the Wax-paper Process. — Can any 

 of your photographic correspondents give me some 

 hints regarding the following difficulties, which I 

 (in common with many other amateurs) have met 

 with in working according to Le Gray's wax-paper 

 process ? 



The proportions I used were exactly those pub- 

 lished by Le Gray, and the paper and other ma- 

 terials were of the description he recommends ; 

 but nearly every picture, on being placed in the 

 gallic acid, was spoiled, by the appearance of 

 numerous small black spots, all well defined on 

 one and the same side, but comparatively un- 

 defined on the other. These may possibly have 

 been owing to iron in the paper, and may there- 

 fore, perhaps, be obviated by following the method 

 of Mr. Crookes. But I am anxious to learn if 

 others have experienced these spots in their pic- 

 tures, and to what they attribute them, as well as 

 how they can best be prevented. 



My second difficulty was in the want of intensity 

 in the pictures, which completely prevented my 

 obtaining even a tolerable impression from them. 

 I tried many different times of exposure, and even 

 after working long with Le Gray's slightly -differ- 

 ent proportions, but always without success. The 

 margin of the pictures, however, which had been 

 exposed to the daylight, always became of the 

 most intense Mack, after the picture had been 

 developed. 



But my third difficulty was the most annoying 

 of all, because the constant source of failure, 

 though in itself apparently the most easily ob- 

 viated. It was the difficulty of keeping the dishes 

 which contained the solution clean ; the effect of 

 this want of cleanliness being the marbling of the 



pictures whenever placed in the gallic acid and 

 aceto-nitrate of silver. This is a difficulty I never 

 before encountered, during half a dozen years' 

 practice of photography (during which I used to 

 be as successful as most of my brother amateurs) ; 

 and though I tried every plan I could think of to 

 insure cleanliness, such as washing the dishes with 

 warm water, nitric and muriatic acids, &c., and 

 afterwards wiping them thoroughly with clean 

 cloths, still the mixture of gallic acid and aceto- 

 nitrate of silver, for developing the picture, 

 brought out some marblings or blotches on the 

 dish, which were invariably communicated to the 

 picture, even though it was only floated on the 

 surface of the solution, and prevented, with the 

 greatest care, from touching the bottom of the 

 dish. Should the dishes be kept in the dark 

 constantly ? 



Have any of your correspondents tried Le Gray's 

 plan of filtering the nitrate of silver through ani- 

 mal charcoal ; or do they find any occasion to filter 

 at all ? With me, the animal charcoal seemed to 

 increase the sensibility greatly. G. H. 



Mr. Archer's Services to Photography. — In 

 Vol. vii., p. 163., Mr. Horne seems very indig- 

 nant at the idea that Mr. Archer taught him to 

 take pictures, and says Mr. Archer's published 

 account will not succeed. Now I know that Mb. 

 Archer and myself did take pictures by his pro- 

 cess as published. I also assert that neither Mr. 

 Horne nor Mr. Fry made any collodion pictures 

 before Mr. Archer published his account in The 

 Chemist, and, with the ordinary camera, that pro- 

 cess must be the one now to give any chance of 

 success, for without washing the plate the collo- 

 dion will not keep five or six hours without stain- 

 ing. But as that process was not sufficiently 

 quick, Mr. Archer proposed to take the pictures 

 in the bath itself; and I have one which I took in 

 that way on the 16th of May, 1851. 



Mr. Horne, I think ungenerously, wishes to 

 detract from Mr. Archer's merit, and to exalt 

 himself and Mr. Fry at Mr. Archer's expense. 

 I have a letter of Mr. Fry's, dated March 23, 

 1852, in which he says, "I with much pleasure 

 accord to Mr. Archer the credit he is fairly en- 

 titled to, of being the sole Inventor of the collo- 

 dion process." And another letter, wherein he 

 says he " never sanctioned the Insertion In any 

 work of any article connected with the collodion 

 process." I also know that Mr. Archer prepared 

 collodion for Messrs. Horne ; that Messrs. Home 

 advertised it as prepared by Mr. Archer ; and 

 that they were glad, when the thing was new, to 

 avail themselves of Mr. Archer's assistance. 



W. Bkown. 



Evvell. 



Mr. Weld Taylors Iodizing Process. — The pro- 

 cess I generally adopt in iodizing paper by tha 



