Flourescent light or any multi cell LED light won't work.
You need single-source light. If you're using those modern energy saving lights, replace them for the time being with regular bulb light.
The strobe also should have a certain dgree of glare so the printed out versions less likely will show you anything.
Timing light from Autozone is available to loan for free(loan a tool program when you first purchase it for the full price and than return with all money back) may do the trick where the blinking frequency is fully adjustable.
You need single-source light. If you're using those modern energy saving lights, replace them for the time being with regular bulb light.
The strobe also should have a certain dgree of glare so the printed out versions less likely will show you anything.
Timing light from Autozone is available to loan for free(loan a tool program when you first purchase it for the full price and than return with all money back) may do the trick where the blinking frequency is fully adjustable.