Ink and a 4 color Press

[printerdw]

Hi There

We are buying a new 4 color press and I have a question? Right now I run a 2 color 14X20 press and I am running toyo ink all with the same Med Tac is it diffrent on a 4 color press should I run the last 2 colors with less tac?

Dennis

[Bob Peterson]

Dennis,

Ink manufacturers will do one of two things when formulating process ink sets.

1. Have a uni-tack series where all of the inks are the same tack with viscosity and yield values adjusted for ideal trap.

2. The inks are step tacked in the KCMY sequence with the black being the highest and the yellow the lowest.

Both of these formulation styles function as designed. I would find out from your supplier if the set you are running is designed to print inline on a 4-color press. If so then you would only need to go to a lower tack yellow and/or magenta to eliminate backtrap contamination or improve trap.

[hazzmatte]

We use Toyo LZ series - (I think all Toyo ink is uni-tack ink) in our 4 color press. What my guys like about it is it doesn't skin if you leave it in the fountains overnight. You will see that cleaning 4 fountains every night can be a real chore. Also is sets up very well meaning less chance of offsetting. Toyo is also a stronger ink so you run a lighter film. This has it pros and cons that I won't get into at this point. But in all, I think using Toyo will work just fine for you.