The next possible cause of the fault is in the toning bath. If too much light reaches the prints whilst here, the defect will occur. Further than this, if any of several foreign substances find their way by accident into the toning-bath, the same is likely to occur. The most likely substance, and one which will infallibly bring about the defect, is hyposulphite of soda. If a few drops of the fixing-bath get into the toning-bath the latter is ruined.
Another danger of the defect is to be found in the fixing-bath itself. If this be acid, it is likely to come about. It is well to make sure that the fixing-bath is not acid by putting into each pint of it a piece of wash ing soda the size of a hazel-nut, or by pouring into it a few drops of ammonia until the solution slightly smells of it, thereby indicating that it has been rendered a little alkaline. The alkalinity of the fixing-bath can do no harm, and ensures its not being acid, which latter is most hurtful.
If the prints be allowed to stick together, either during fixing or immediately after in the washing water, yellow ness of the lights may occur.
Time Shadows of the Print have a bronzed appearance.
This appearance only occurs when a negative having very strong contrasts is used with paper which has been sensitised on a very strong silver bath. Very often the disagreeable appearance will pass away in the fixing-bath.
At times, however, it is so strong that it does not. In such a case we must use a weaker sensitising bath.
The Prints lack contrast.
If this defect be not due to the negative it is due to the sensitising bath being too weak. In this latter case there accompanies the lack of contrast a peculiar defect to which the name of " meanness " has been given. This we describe here.
The Prints are "mealy." This word is used to describe an appearance of print which is most disagreeable. Instead of the deeper shadows being of an even dark hue, they are of a freckled nature, and as a rule the colour of them is not agreeable.
As just mentioned, this defect may arise from the fact that the sensitising bath is too weak. In this case the evident course is to strengthen it. It also arises from the use of an acetate toning-bath which has been kept for too short a period. If it be found that an acetate bath which has been kept for twenty-four hours gives mealy prints, the next one used should be mixed up with boiling instead of cold water.
There is a _powdery deposit over the surface of the Prints.
This defect may make its appearance if the prints have been allowed to lie face upwards in the washing water before toning. The evident remedy is not to leave them so.