i have a terrible proplem in printing with metalize paper. i try to get rich color so that too more ink and water come together. the ink get into too much on water form roller. is it emulsification? and how to fix it? sorry for my bad english. you are all welcome
When running metalized stock you need to start with water speeds way down, possibly 25 to 35 % less than runnin say c1s or a form of text paper. Make sure your running specific top drying ink(hard surface inks) as this type of stock has a top coat that is not porous like c1s. A lot of times a base white is applied first (conventional or uv) so your inks can appear pleasing. Printing over virgin metal will give you a mottled/cloudy look. Different ink series have different properties for surface,drying etc. Some inks like metallic s start out slowly accepting water into the ink train......then they really soak it up and can emulsifiy and cause problems once they get going . Gold are notorious for this , silver not as bad.... Metal and film work are touchy,always have to keep your eyes open.
As mentioned, water feed on any non porous stock will need to be cut down significantly. If you run paper waste to get up to color you will find that one you get to the metallic stock your image will wash out. I know your not going to want to hear this but..... you will need to do either one of 2 things. Buy enough additional metallic stock to be able to do the make ready on the actual stock, or.... get your press up and running quickly and get color and ink water balance on the fly. To run books of paper waste through the press in an attempt to save money on stock will not work well for you. It seems that when it comes to estimating these sort of jobs the tendency is to estimate based on minimal waste because the stock is so costly. Management needs to either find a way to reconcile the cost, and buy additional paper, or be willing to accept some of the issues that come with this sort of work. The very best advice I can offer when it comes to these 'specialty" sort of jobs is to farm them out to the people that do it all the time. This will usually mean a specialty printer with UV equipment staffed by press crews that do it day in and day out.
when i increase the viscosity of the water by adding too much alcohol(about 40%) and the proplem disappear but the color is too bad especially gold color. i dont know why and the dampening additive i used is hydrofix with 2% amount. is there any advices. thank you
Im not at all suprised that you are encountering excessive emulsification when running alcohol at 40%. Even on the old school Dalgrehn dampening systems that were around 30 years ago 40% alcohol would be WAY too much. On any modern continuous flow dampening system there should be no need for alcohol percentages exceeding 5%. If you can not print cleanly with 5% alcohol, then I say something is wrong with either your damp settings, roller durometers,presses general state of repair, or competency of press crew.
@giaminh 40% alcohol in your dampening will trouble you all the time even you print UV or conventional ink. The stardard alcohol should be 8-10% and 2-4% hydrofix (in case you are using 2%, please check your pH, if your pH is higher 5.5, please add some more Hydrofix) Anyway, you need to keep your dampening solution in standard first, then please look at your machine. You did not mention anything about your machine condition and the setting of the rollers; this is very important, too. Therefore please keep your rollers setting as manufacturer standard if you could do or ask for helping if you are not confident. If these two main things has been tried but your issue remains, let think about your UV ink and Hydrofix combination (you could try other ink or chemical...) P/S: if you still can not find the solution, please think about a help from technical expert in your area. (VN - I guess)
