FRILLING A trouble to which negatives are liable while undergoing treatment in the various solutions ; the edges of the gelatine film leave the glass plate and are cockled. It is due to the uneven temper ature of the solutions, excess of soda or other alkali in the developer, handling the negatives with the warm fingers, the use of strong fixing solutions, or to rapid washing, the water being allowed to impinge upon the edges of the plates in such a way as to lift the films. Frilling may be prevented by hardening the film before or after development with formaline, or a com bined fixing and hardening bath may be used. If no precautions are taken and the gelatine is found to be frilled, it may be more or less remedied by treating with methylated spirit. Frilling is allied to the far more common defect of blistering, and the remedies given under a separate heading for the latter apply equally well for the former. Frilling often appears on
print-out papers when they are torn, as, for example, when a half-plate piece is torn into halves for use as quarter-plates. Printing papers should always be cut clean, because rough edges allow the water to get easily under the films, so causing frilling.
Two old-fashioned but serviceable methods of preventing plates from frilling may be mentioned. One is to soak the dry plate before development in a saturated solution of Epsom salts, and the other is to rub a wax or tallow candle round the exposed dry plate on the film side, before wetting it with the developer. Neither of these, however, is as reliable as immersion in a 10 per cent. solu tion of formaline. (See also " Hardeners " and " Blisters.")