Early Work In Photography
A Text-book For Beginners

First Lessons in Printing. Il effected by light. This is the principle upon which the operation, known as “ fixing,” is based. Sodium thiosulphate (commonly known as " hypo ") pos- sesses the power of attacking and dissolving the sensitive salts of silver existing in the paper, without attacking those parts which have been altered by the action of light. We will, therefore, make up a small quantity of solution, called by photographers “the fixing bath.” Hypo •".....................................3 ounces. Water ................................... 20 ounces. The hypo must be quite dissolved in the water, and the solution must be used cold, otherwise the gelatine coating of the sensitive paper would probably be dissolved. In order to render the prints insensitive to further light action, we must immerse them singly in clean cold water, until they lie flat and limp (about 15 minutes), and then transfer them to the fixing bath, which may be contained in a basin or deep soup plate or, better still, a deep porcelain tray* (about 7 by 5 inches), which may be had from a stock-dealer for about tenpence. While they are in the fixing bath, the prints must be kept moving constantly—lifting tlie bottom print to the top, slowly and steadily—examining each print and removing air bells if any are formed on the surface. Fifteen minutes in the fixing bath will be sufficient to thoroughly remove all the sensitive silver salts from the prints, which must then be freely washed in several changes of clean cold water, in which they must be con- stantly moved in order to permit the water to act freely upon their surfaces. When we say immerse singly, we do not mean that only one print Deep Porcelain Tray. may be fixed at a time, but that a lot of prints must not be dumped in together, otherwise they would stick to each otlier. Directly one print is quite immersed—another may follow, and so on until all are in the bath. Two dozen Jplates may be fixed in twenty ounces of fixing bath, and after use the bath must be thrown away; never attempt to keep it for a day or two after once fixing a batch *This tray must be reserved exclusively for use with hypo, and for washing the prints after fixing. On no account must it be used for any other chemical if it has once been used for hypo, nor must it be used to wash prints before fixing them, as a contamination of this salt would certainly be a fruitful source of failure and vexation.