Photographic Notes. or 
and celebrated histrionic performers on the nights of their 
appearance, etc. The mixture of Dr. Piffard, in which about one 
gramme of magnesium powder is sprinkled over half a gramme of 
gun cotton, placed on a sheet of metal, is very useful in this 
respect. The mixture is deflagrated at about three yards from 
the sitter, and the quantities mentioned are just sufficient to obtain 
an excellent portrait. The colouring matter, eoséve, is now in 
considerable demand for preparing what are termed orthochromatic 
plates, and a large number of other organic or coal-tar colouring 
matters are at present being assayed for the same purpose. 
Bichromate of ammonia is being used in many printing establish- 
ments in lieu of bichromate of potash, The new “ photo- 
chlorides” are also likely to find practical application in the same 
manner. 
To make Ruby Glass.—There was recently published in the 
Philadelphia Photographer a method for producing ruby glass 
(nitrate of silver and gelatine). I had worked out a practical 
formula, viz. -— 
No. I. 
Gelatine (Heinrich’s) it ss) ESO) BEANS: 
Water ame eae Sac 6 ounces. 
Chloride of Ammonium ... 6 3 grains. 
Soak for one hour, melt, and add No. 2, drop by drop, stirring 
with a glass rod. 
Now ae 
Water ace e: 4 ounce. 
Nitrate of Silver ase we = 30 grains. 
To produce a very fine chloride of silver, filter through two 
thicknesses of flannel, at a temperature of 160°) B.3 coat the 
cleaned warm glass with this, using one ounce of the compound 
for each 10 by 12 glass. A levelling-stand must be used to 
preserve an even coating. All of the work can be done in white 
light. Dry the plates and expose to sunlight. A deep orange 
ruby glass is the result. It is very safe for all sensitive plates, — 
Wm. Bell, in Philadelphia Photographer. 
Retouching Unvarnished Negatives.— Powder a small piece 
of rosin ; sprinkle a glass plate with the powder thus obtained, 
mixed with about one-third of its volume of cigar ashes, so as to 
render the rosin less viscous, less glutinous. The mixture is 
placed in a clean little gauze bag, well washed, and with it touch 
the plates that are to be retouched. It suffices to take a very 
small quantity on the end of the finger, and pass it lightly over the 
places that need retouching, to render the coating mat apt to 
receive the pencil. Photo. Archives. 
