Ink-fountain Solution Emulsion in Offset Printing Studied Using Confocal Microscopy

Development of a new method for the visualization and measurement of fountain solution (FS) droplet size distributions in lithographic inks using confocal microscopy is described. The quantity and the state of FS droplets in offset inks are important as they significantly affect ink transfer and drying properties. The application of the confocal microscopy technique offers the possibility and versatility to study FS in ink emulsion through careful choice of fluorescent dyes and selection of suitable experimental conditions. This method has, for the first time, enabled the visual examination of the FS droplets in a 3D form. With the choice of suitable software, this method has the potential to provide quantitative information of the droplet size and size distribution. Some problems associated with the confocal method are also discussed. This method may have wide application in studying FS/ink, FS/plate and FS/paper interactions.