_A Query respecting Collodion._--I have been making some collodion by Mr.
Tery's process, and have iodized it with a very sensitive medium. The
collodion is very clear and properly diluted. The ether I used had a very
powerful smell of sulphur, and was likewise very strong and volatile. I
diluted it with an equal {526} volume of alcohol. The ether was then still
very strong. The cotton dissolved freely. On mixing the iodizing medium,
the colour of the collodion turns immediately to nearly a port-wine colour,
but still remains very clear. I obtain a very good film of iodide of silver
from the bath, but cannot produce a picture under five or seven minutes,
whereas with the same lens, and the same iodizing medium, viz.
Alcohol 8 drms.
Iodide of potassium 8 grs.
Iodide of ammonium 4 grs.
Iodide of silver ½ gr.
I have obtained beautiful pictures in less than one second with collodion
prepared by the same (Archer's) process. As I have made a quantity of it,
and am unwilling it should be wasted, I have taken the liberty of asking
your opinion on the subject. Do you think the collodion is too new, or the
ether not good? On pouring the developing solution on the plate
(protosulphate of iron), the plate has the appearance of having ink poured
on it; but this appearance is removed on the application of the
hyposulphite of soda, and the plate remains as clear as when it was taken
from the nitrate of silver bath.