Page:TheAmericanCarbonManual.djvu/85

 —This defect arises from unequal and insufficient pressure in transferring. This unequal pressure may arise from the coating of India-rubber being uneven, or, more probably, from the coating of clear gelatine being applied in uneven streaks, or from uneven texture of blanket, or uneven pressure.

—This will arise from the face of the print being imperfectly coated with gelatine, or from the paper or board to which the print is transferred having an imperfectly moistened surface, or from not being dry when the paper is removed, or soiled by fingering or dust.

is caused by imperfect washing of the print, by which traces of soluble chromic salt are left in the image.

—This arises from the tissue having imbibed the bichromate solution unequally. If, in immersing the tissue, one portion remains dry while the rest is wet, that portion will be least sensitive, and will form a light patch in the picture. If the tissue is raised out of the bichromate in such a manner that streams of the solution run down the sheet, there will be in the print patches or streaks of a darker color, corresponding to the streams of the solution. The attachment of a strip of paper along the lower edge of the tissue, immediately after it has been hung up to dry, helps