Photography

This subject is worthy the attention of every operator. The following process is so plain and easy of trial that any Daguerreotypist can try it. This is as given by Mr. James Campbell, and was published in Humphrey's Journal of the Daguerreotype and Photographic Arts, vol. 5, page 11. Mr. Campbell has done much to further the process announced by M. Neipce, and his experiments have proved highly successful.

The following is submitted as worthy of trial:

Hyposulphite of Soda.--This salt forms one of the important chemicals for the Daguerreotype operator. Its application to this art is of an interesting nature. It is used to dissolve the sensitive salt of silver which remains unchanged during the exposure in the camera. It has the property of readily dissolving the chloride, bromide and iodide of silver. It should be pure and free from sulphuret of sodium; should this last be present, it will cause brown spots of sulphurated silver upon the Daguerreotype impression.

I have produced some interesting specimens of the Daguerreotypic art, by exposing in the camera only a portion of the sensitive plate to the action of light. When on the exposed portion an image is formed, then taking the tablet into the dark room, change ends and expose the sensitive portion, and produce another image, developing as usual. This plan is adapted for taking likenesses for lockets. Two images can be presented as sitting side by side, by covering half the plate with black paper, and exposing as before.

Remarks on the Accelerating substances Used in the Daguerreotype.--I have now arrived at a point in this work, where the eye of the Daguerreotype public will intently search for something new. This search will prove in vain, at least so far as regards those who have enjoyed and embraced the opportunities for studying the principles of our art.

Regarding specks from bad water, I would remark that gilding should be made only with distilled water. Thus made, it produces very little deposit, even by long keeping. It therefore preserves its original strength, and works with great uniformity.

Hydrate of Lime.--The operation by which water is combined with lime is called slaking. Take a piece of quick lime, common lime used in mortar, and immerse it in warm water for about fifteen seconds; then place it in an iron or tin vessel. It will soon begin to swell, evolving a great deal of heat and emitting steam, and soon falls into a fine powder, hydrate of lime. This should be well stirred and allowed to cool, and then bottled in order to prevent it from giving off the hydrate and recovering the carbonic acid from the atmosphere.

The following is from Humphrey's Journal, vol. 5, and from the pen of Dr. WM. HARRINGTON, one of the most able writers upon the subject of the Daguerreotype in this country: