Abstract: The present invention provides systems and methods for providing colorant to a colorant cup apparatus that is adjacent to a pad printing cliché. The fluid colorant is fed from a colorant container through a feed conduit to the cup and an inline viscometer external to the colorant container measures the viscosity of colorant within the feed conduit. A control mechanism can dispense colorant solvent into the colorant container based upon a viscosity measurement performed by the inline viscometer. The disclosed systems, colorant cups and methods are useful in the preparation of tinted contact lenses.