Surfactants are incorporated in most fountain solutions. These types of surfactants provide a uniform water transfer and enhance the efficiency on wetting the printing plate. Available on the market are a broad range of surfactants. Some of these surfactants have serious negative effects, such as excessive foaming, ink emulsification or even plate blinding.
For these reasons, Shadowfax has put a lot of effort on R&D and testing on the selection of the correct types of surfactants. This ensures that our range of products will provide the best possible performance and workability, without the undesirable side effects.
In the process of offset lithographic printing, the correct dosing of fountain solution is very critical. Shadowfax fountain solutions are formulated to run in a range of 2 – 4% on the press. This is based on the type of presses and dampening systems, water quality, etc. Maintaining the recommended dosing range is therefore very important. Dosing a fountain solution at the recommended concentration will ensure that all of its components are at a correct concentration.
Running a fountain solution at below or above the recommended level will inevitably result in problems:
All these factors will end up with poor print quality, more wastage generated, time consuming, and lower productivity.
A good fountain solution will also include a level of defoamer (anti-foam agent) to prevent a foam formation in the re-circulation tank. Despite the presence of defoamer in the fountain solution, foaming can still occur due to mechanical reasons i.e. incorrect machine settings, poor machine maintenance, contamination from paper, ink or blanket wash or high pressure of the re-circulation pump.
Methods of resolving foaming issues: 1) to check that the return control valve and the water return is set at a proper pressure and flow rate; 2) Check and wash the filters in the recirculating tank or replace it if it’s contaminated and 3) flush and clean the fount tank on a regular basis (bi-weekly/monthly) .
However, if the foaming is evident due to any of the above listed factors, as a short term solution, we recommend our SC112 – CREST® Antifoam to eliminate the foam in the fount tank. Customers can use a small amount of SC112 – CREST® Antifoam to eliminate the foam instantly. You may refer to the instructions from the product technical data sheet. Upon completion of a print job, always flush and clean out the re-circulation system. Therefore, any contaminants which are causing the foaming problem will be flushed out of the system.