Rolling the Prints.—After the prints have been under the hands of the retoucher, they should be rolled in a rolling-press in order to give a brightness to the printed image. It would be invidious to point out any particular press that should be used. Suffice it to say, there are many excellent ones in the market. The directions for cleaning and using the press are supplied with each machine; we therefore refrain from saying anything about them.
[CHAPTER XXIII.]
DEFECTS IN PRINTS.
The bath solution is sometimes repelled by the paper, and this is found chiefly in highly albumenized paper, and is generally caused by the paper being too dry. Passing the sheet of paper over the steam from a saucepan will generally effect a cure.
Small white spots, with a black central pin-point, are often met with in prints. Dust on the paper during sensitizing will cause them, the grit forming a nucleus for a minute bubble. All paper should be thoroughly dusted before being floated on the sensitizing bath.
Grey, star-like spots arise from small particles of inorganic matter, such as ferric oxide, lime, &c., which are present in the paper. They become more apparent by decomposition during the printing operations. They may generally be discernible by examining the paper by transmitted light.
Bronze lines (straight) occur through a stoppage during floating the paper in the sensitizing solution. Should the lines be irregular, forming angles and curves, it is probable that a scum of silver oxide, &c., may be detected on the surface of the sensitizing solution. A strip of blotting-paper drawn across the bath will remove the cause of the defect.
Should the print appear marbled, it may be surmised that the sensitizing solution is weak, or that the paper has not been floated sufficiently. In some cases it may arise from imperfect albumenizing; but in ordinary commercial samples the cause can be easily traced.
Red marks on the shadows may appear during toning, and are very conspicuous after fixing. They generally arise from handling the paper with hot, moist fingers after sensitizing; greasy matter being deposited on the surface, prevents the toning bath acting properly on such parts.
Weak prints are generally caused by weak negatives. Such can be partially remedied by paying attention to the strength of the sensitizing bath (see [Appendix]), and by using washed paper.