Aug. 6. 1853.] 



NOTES AND QUERIES. 



133 



PHOTOGRAPHIC COBRESPONDENCE. 



Glass Chamhers for Photography. — I am de- 

 sirous to construct a small glass chamber for 

 taking portraits in, and shall be much obliged if 

 you can assist me by giving me instructions how 

 it should be constructed, or by directing me where 

 I shall find clear and sutficient directions, as to 

 dimensions, materials, and arrangements. Is it 

 essential that it should be all of violet-coloured 

 glass, ground at one side, as that would add a good 

 deal to the expense ? or will white glass, with thin 

 blue gauze curtains or blinds, answer ? 



Probably a full answer to this inquiry, accom- 

 panied with such woodcut illustrations as would 

 be necessary to render the description complete, 

 and such as an artificer could work by, would 

 confer a boon on many amateur photographers, as 

 well as your obliged servant, C. E. F. 



[In the construction of a photograpliic house, we 

 beg to inform our correspondent that it is by no means 

 needful to use entirely violet-coloured glass, but the 

 roof tliereof exposed to the rays of the sun should be 

 so protected ; for although the light is much subdued, 

 and the glare so painful to the eyes of the sitter is 

 taken away, yet but few of the actinic rays are ob- 

 structed. It has been proposed to coat the interior with 

 smalt mixed with starch, and afterwards varnished ; but 

 this does not appear to have answered. Calico, both 

 ■white and coloured, has also been used, but it is cer- 

 tainly not so effectual or pleasant. Upon the whole, 

 we think that the main things to attend to are, firmness 

 in its construction, so as to avoid vibration ; ample 

 size, so as to allow not only of room for the operator, 

 but also for the arrangements of background, &c., and 

 the sides to open so as to allow a free circulation of 

 air ; blinds to be applied at such spots only as shall be 

 found requisite. Adjoining, or in one corner, a small 

 closet should be provided, admitting only yellow light, 

 which may be effectually accomplished by means of 

 yellow calico. A free supply of water is indispensable, 

 which may be conveyed both to and from by means of 

 the gutta percha tubing now in such general use. We 

 apprehend, however, that the old proverb, " You must 

 cut your coat according to your cloth," is most es- 

 pecially applicable to our (juerist, for not only must 

 the house be constructed according to the advantages 

 afforded by the locality, but the amount of expense 

 will be very differently thought of by different persons : 

 one will be content with any moderate arrangement 

 which will answer the purpose, where another will be 

 scarcely satisfied unless everything is quite of an orne 

 character. ] 



Dr. Diamond's Replies. — I am sorry I have 

 not before replied to the Queries of your cor- 

 respondent W.F.E., contained in Vol.viii., p. 41.; 

 but absence from home, together with a pressure 

 of public duties here, has prevented me from so 

 doing. 



1st. No doubt a small portion of nitrate of 

 potash is formed when the iodized collodion is im- 



mersed in the bath of nitrate of silver, by mutual 

 decomposition ; but it is in so small a quantity as 

 not to deteriorate the bath. 



2nd. I believe collodion will keep good much 

 longer than is generally supposed ; at the be- 

 ginning of last month 1 obtained a tolerably good 

 portrait of Mr. Pollock from some remains in a 

 small bottle brought to me by Mr, Archer in 

 September 1850; and I especially notice this fact, 

 as it is connected with the first introduction of the 

 use of collodion in England. Generally speaking, 

 I do not find that it deteriorates in two or three 

 months ; the addition of a few drops of the iodizing 

 solution will generally restore it, unless it has be- 

 come rotten : this, I think, is the case when the 

 gun cotton has not been perfectly freed from the 

 acid. The redness which collodion assumes by 

 age, may also be discharged by the addition of a 

 few drops of liquor ammonia;, but I do not think 

 it in any way accelerates its activity of action. 



3rd. "Washed ether," or, as it is sometimes 

 called, " inhaling ether," has been deprived of the 

 alcohol which the common ether contains, and it 

 will not dissolve the gun cotton unless the alcohol 

 is restored to it. I would here observe that au 

 excess of alcohol (spirits of wine) thickens the 

 collodion, and gives it a mucilaginous appearance, 

 rendering It much more difficult to use by its 

 slowness In flowing over the glass plate, as well as 

 producing a less even surface than when nearly all 

 ether is used, A collodion, however, with thirty- 

 five per cent, of spirits of wine, Is very quick, 

 allowing from Its less tenacious quality a more 

 rapid action of the nitrate of silver bath. 



4th. Cyanide of potassium has been used to re- 

 dissolve the Iodide of silver, but the results are by 

 no means so satlsfactoi'y ; the cost of pure iodide 

 of potassium bought at a proper market is certainly 

 very inconsiderable compared to the disappoint- 

 ment resulting from a false economy. 



H. W. Diamond. 



Surrey County Asylum. 



Trial of Lenses. — When you want to try a 

 lens, first be sure that the slides of your camera 

 are correctly constructed, which Is easily done. 

 Place at any distance you please a sheet of paper 

 printed in small type ; focus this on your ground 

 glass with the assistance of a magnifylng-glass ; 

 now take the slide which carries your plate of 

 glass, and if you have not a piece of ground glass 

 at hand. Insert a plate which you would otherwise 

 excite in the bath after the application of collodion, 

 but now dull It by touching it with putty. Ob- 

 serve whether you get an equally clear and well- 

 focussed picture on this ; If you do, you may con- 

 clude there is no fault In the construction of your 

 camera. 



Having ascertained this, take a chess-board, and 

 place the pieces on the row of squares which run 



