Pure water may be always had ready for use, by keeping a large bottle full of the common water standing out-door in the sunlight, adding a grain of silver from time to time as the bottle is emptied and replenished.
The new "agate iron ware" pots are the best for use as evaporating dishes. They will not break or crack, and they are not nearly so expensive as porcelain dishes.
There are a thousand and one formulæ for developing solutions for the wet plate, but they are all composed of protosulphate of iron or a compound thereof, acetic acid, and water, with the addition of some organic substance, such as sugar, rock candy, glycerine, etc. etc.
The development of a negative is nothing more than the deposition of metallic silver in a state of fine sub-division upon a base of the same metal, which is the image latent in the collodion film after exposure in the camera. And it is supposed that the finer the deposit [p034] secured in the development the better will be the chemical effect and printing quality of the resulting negative. Therefore, the use of organic bodies in the developer is supposed to effect or induce a finer deposit. The careful observer, however, will soon discover that the success of the development depends more on the time of exposure, the temperature of the developing solution and the condition of the bath, than upon any adventitious aids, such as rock candy, etc.
A developing solution, composed alone of an aqueous solution of protosulphate of iron and acetic acid, can be made to produce the finest effects possible to the process.
Half fill with protosulphate of iron a wide mouth 64 oz. bottle, fill up full with water, set aside to dissolve, shaking the bottle once in awhile, so that the water may become saturated. Put a small glass funnel on a stand, so that you can place under it a 16 oz. bottle; fill the 16 oz. bottle with water and enough of the strong iron solution to make a twenty grain to the ounce solution, add one ounce of acetic acid, pour all into the filter and place the bottle beneath the funnel to receive it. This filtered solution is the developer for negatives.
Some experience is necessary to enable one to develope a negative properly and secure the best results.