A Condensed Table of Failures and Remedies for Carbon Printing.

265. Failure

Failure. The pigmented gelatin shows signs of dissolving in the sensitizing bath, especially when touched with the fingers.

Cause. - Too warm a sensitizing bath.

Remedy. - The sensitizer should not be warmer than say 50° in summer, and not over 70° in winter. In summer the bottle containing the solution should be placed in cold running water, or the sensitizing bath should be placed in a large water bath, to which pieces of ice have been added.

266. Failure

Failure. During drying the tissue shows signs of running.

Cause. - Too warm a drying-room.

Remedy. - A better ventilated room, or one fitted with fans. The addition of alcohol to the sensitizing solution is also recommended.

267. Failure

Failure. The pigmented gelatin will not dissolve in the warm developing bath, even in those parts that have received no light.

Cause. - The drying took too long, owing to dampness of air; or, the tissue has been attacked by fumes from gas or oil; or an old sensitizing bath has been used.

Remedy. - The ventilation of the drying-room must be attended to, so that the tissue can dry quicker. Filter sensitizer always after use, and keep it fresh. See, also, remedies given in Paragraph 266.

2G8. Failure. - The highest lights dissolve out during development, but not the other parts of the print.

Cause. - Too long an exposure.

Remedy. - Add a few drops of liquid ammonia to the developing water. If the detail in the shadows do not then appear, another print must be made, giving shorter exposure.

269. Failure

Failure. Dark spots or streaks are discernible on the print.

Cause. - Failure to blot off the excess of the sensitizing solution, rendering some parts more sensitive than others.

Remedy. - Be careful to blot off all superfluous sensitizer when squeegeeing the print.

270. Failure

Failure. The prints have too hard or chalky appearance.

Cause. - Too weak a sensitizer, or too much ammonia added to the developing water.

Remedy. - Use a weak sensitizer-say one to two per cent. strength-for soft negatives, adding as much ammonia as will turn it to a pale yellow color. For strong negatives use a five per cent. solution with no ammonia.

271. Failure

Failure. Print develops flat.

Cause. - The sensitizing solution has been made up too strong.

Remedy. - Same as for last.

272. Failure

Failure. The print has a fairly good appearance, but the half-tones are eaten away.

Cause. - Development was started in water that was too hot, or the hot water was added during development; also caused by too much agitation of the water during development.

Remedy. - The temperature of the water should not be over 100° Fahr. Also avoid agitating the water too violently.

273. Failure

Failure. The print shows slight reticulation. Cause. - Too sudden a change in temperature of baths, or water too hot during development.

Remedy. - Raise temperature of developing baths gradually-not to exceed 100° to 105°.

274. Failure

Failure. Shining round spots appear on the transferred print when the support is rough.

Cause. - The support was not left in the water bath long enough before transferring, or sufficient pressure was not applied when squeegeed.

Remedy. - Heavy rough transfer paper should be allowed to soak in clean water for from one-half to two hours before being squeegeed to the tissue. Also, they should be dipped in a bath of water at 110° just prior to being brought into contact with the tissue. Also, greater pressure should be applied during squeegeeing.

275. Failure

Failure. Small shining points are visible on the outline of transfer prints.

Cause. - Due to too much air in the developing water, and also water too cold; also transfer paper not left long enough to soak in water.

Remedy. - Use warmer water for development and for soaking the transfer paper.