Study of PG-Added Fountain Solution for Printing Offset Technique

Although the printing technology, especially offset printing, has changed and grown quickly based on advanced invention and production capacity. However, the old offset machine printing such as one or two colour offset machines are still used massively in development countries. It is unpredictable when the old printing technology eliminated completely from the community, since it is affected by the economic level and extraordinary need of the public such as public election. The old machine which has been produced for more than 10 years usually has an issue related to the ink-water balance (iwb). The use of propylene glycol (PG) as single wetting agent improved iwb based on our previous study. Therefore, the effect of PG with fountain solution to the print quality is studied here. A series of fountain solution (FS) with additional content of 0 ppm, 13 ppm, 20 ppm, 40 ppm of PG was used to print an image on the art paper surface using sakurai offset machine. The optical parameters such as optical density (OD) and L*a*b were used to observe the effect of PG content in FS to the quality of printing. The OD on 0 ppm (reference), 13 ppm, 20 ppm and, 40 ppm of PG were 1.76 (reference), 1.83, 1.76, and 1.74, respectively. The optical density was identified as the maximum value at 1.83 on raster 100% of black colour for PG 13 ppm. At 13 ppm PG-added FS, the ΔE values of black (K) and Magenta (M) were 5.2 and 9.8, respectively, while ΔE values of cyan (C) and yellow (Y) were 1.7 and 1.8, respectively. It meant at PG 13 ppm, the K and M were stronger than the reference, while C and Y were equal. The same and lower OD compared to the reference showed unimproved color. Keywords: offset printing, fountain solution, propylene glycol