EXCESSIVE CONTRAST.
The print possesses excessive contrast, with greenish-black shadows, and is want ing in detail in high lights. Causes.— (a) Too brief exposure, causing the print to be developed too long in hopes of obtain ing detail in high lights ; or (b) the nega tive is too hard for the process. Reme dies.—(a) Passing by the obvious remedy of giving longer exposure next time, which, generally speaking, would meet the case, it being cheaper to throw away the spoilt specimen and produce another, the print may be reduced by immersion in the iodide or ferricyanide reducer ; though perhaps the best reducer is persulphate of ammonia. Immerse the print in a 2 per cent. solution of ammonium persulphate until the shadows are sufficiently reduced, then transfer to a 5 per cent. solution of soda sulphite for a few moments and wash ; (b) If a large number of bromides are to be made, it will be best either to reduce the negative or to reproduce it with softer contrasts. Failing this, the most rapid paper should be used and a dilute de veloper, and the negative exposed as near to the light as practicable.
FOG.
The print is fogged. Causes.—Fog may be either " chemical " or " light." If chemical, it may be caused by (a) an error in manufacture, (b) impro per storage, (c) having the developer too strong, (d) over-development, (e) hypo. in developer. The causes of light fog are various, and will doubtless suggest them selves, such as unsafe dark-room lamp, exposing the paper too long to the rays of the lamp, etc. Remedies.—(a) This is the least likely, but if suspected, return the sample to the makers. (b) Carefully consider the conditions of storage. If purchased from a chemist, inquire how long it has been in stock. (e) The de veloper should never be so strong as for plates. It is customary to use it at only half the strength by diluting with an equal bulk of water. (d) Remove the print from the developer the instant it shows the required detail in high lights. This should he arrived at in two to three minutes ; if it is not, the exposure was too short or the developer too weak. (c) Exercise more care in dealing with the hypo. solution.