Therein lies the rub:
>the ideal resistivity of the silver ink traces would be less than 5 times that of bulk silver.
>The ideal resistivities were not met, and the resistivity of the sample ink traces ranged from five to ten times the bulk resistivity.
Are you saying the traces are too resistive, or not resistive enough? How would that manifest - i.e. I see working circuits on the video, but are there classes of circuits that this would not work for?
You can compensate by making traces wider to get a lower resistance from the same resistivity, or by running circuits slower (digital circuit speed is often limited by the RC time constant where C is parasitic capacitance of an input somewhere — a higher-resistance trace takes longer to charge up the input gate capacitance). How hard it is to adjust for the higher resistivity will depend on the circuit, of course.
One can also use high intensity light to "weld" the silver particles together without damaging the plastic substrate. This requires an expensive setup but improves conductivity drastically... https://en.wikipedia.org/wiki/Photonic_curing