PHOTOGRAPHIC CORRESPONDENCE.
Simplicity of Calotype Process.—The session of the Photographic Society was commenced with a paper from our original correspondent, Dr. Diamond, under the above title. Our journal having led to such facilities of question and answer, has induced many of our readers to ask upon several points additional instructions, some of which we have ourselves thought might have been made more clear and having written to Dr. Diamond he has promised us a revised copy for our next Number. Replying to some of our Querists, he says, "The plain photographic facts are correct; but I wrote the paper on the morning of the day on which the Society met, and was not aware it was to be printed in the Journal until I received my copy."
Albumenized Paper.—As my only object writing on this subject was to communicate to others the plan which I had found in practice most successful, I think it necessary to correct some points of misapprehension which it is evident your correspondent K. N. M. has fallen into, Vol. viii., p. 501.
In the process I recommended, the paper, if cockled up, readily becomes flat and even if kept in a portfolio or any similar receptacle; and as I never float my paper to sensitize it, I have not the inconvenience of the silver solution becoming spoiled by particles of the albumen. The 100 grains to the ounce for the solution I do not find more extravagant when applied, as I have indicated, with a glass rod, than one of 30 grains to the ounce when the paper is floated, because in the former case I use only just enough to cover the paper, viz. forty-five minims to a half-sheet of
Canson's paper, and there is no loss from any portion adhering to the dishes, evaporation, or filtering. This is far more than would be imagined when only a sheet or two of paper is required at one time. Lastly, with regard to the strokes being visible after printing the positive, I do not find them so in general, though occasionally such a thing does happen when sufficient care has not been taken in the preparation; but I find striæ quite as visible on two positives prepared by Dr. Diamond himself, which he kindly gave me: however, I will forward a sample of my paper for your judgment, and also a portion for K. N. M. if he will take the trouble of trying the same.
Geo. Shadbolt.
New Developing Mixture.—Having for some months past used the following developing mixture, and finding it very bright and easily applied, I beg to offer it to your notice. It does not cost more than three farthings per ounce, and therefore may be worth the consideration of beginners. I do not know a better where the metallic appearance is not desired.
No. 1. Pyrogallic acid 2 grains.
Glacial acetic acid 1 drachm.
Water 1 oz.
No. 2. Protosulphate of iron 10 grains.
Nitric acid 2 drops.
Water 1 oz.
To six drachms of No. 2. add two of No. 1.
I pour it on, but do not return it to the bottle, as it is apt to spoil if so used.
T. L. Merritt.
Queries on the Albumenized Process.—Allow me to put a few questions through your valued paper.
In the albumen process on glass, Messrs. Ross and Thomson, in Thornthwaite's Guide, recommend 10 drops of sat. solution of iodized potassa to each egg. Now is it meant ten drops, or ten minims? If the former, a drop varies with the bottle and quantity of liquid in it; and ten drops are nearly half the bulk of ten minims, generally speaking. Then as to the egg: an egg in this country is only at most 6
A Subscriber.
Bombay.