Moisture Conditioning of Paper

Paper is moisture conditioned so that it will stay flat and not develop wavy or tight edges before or during printing. Wavy-edged paper can be temporarily corrected by storage in “hot room” temperatures (100º to 110ºF) for several hours before printing, or by placing strip heaters or infra-red lamps along the sides of the feeder pile near the top to warm and shrink the edges.

HOURS REQUIRED FOR TEMPERATURE CONDITIONING PAPER
Cubic Volume of Paper on Skid, in Carton or in Roll		Difference in Temperature of paper and Temperature of room in which it is opened
10º	15º	20º	25º	30º	40º	50º	60º
6 ft3 (1.83 m3)	5	9	12	15	18	25	35	54
12 ft3 (3.66 m3)	8	14	18	22	27	38	51	78
24 ft3 (7.32 m3)	11	16	23	28	35	48	67	100
48 ft3 (14.64 m3)	14	19	26	32	38	54	75	109
96 ft3 (29.28 m3)	15	20	27	34	41	57	79	115

* Above information from Graphic Arts Technical Foundation Research Progress Report No. 44 Over-drying will produce tight edges. On one and two-color presses, wavy-edged paper may need to be treated before each printing. Dry or moist paper should be hung in a conditioning machine in lifts of 25 to 50 sheets depending on the weight of the paper. Modern machines use blowers and humidifiers, take little space, and require only 2 to 8 hours to condition paper. Kallima products are delivered with a moisture proof barrier. The paper should remain wrapped in its moisture proof barrier until the paper is acclimatized to the print room conditions. The ideal print room conditions are 50% RH and 23°C (73°F). Failure to allow cold paper to reach the press room temperature can result in water condensing on the paper. This can cause wavy edges and creases during printing and converting resulting in misregistration and ink setting problems.

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