Since when is the purple dye in Royal Purple thermally stable? It used to be this stuff lost its color after just a few hours of run-time.
Seeing the oil on the dipstick should only be a problem after you first change it. once it turns a bit amber, then brown, seeing it (after the engine has been sitting for an hour or more.
Even when clean, I wipe the dipstick thoroughly then re-insert, pull and re-examine. Hold the dipstick up so the light stikes it and look the shiny section at the very tip. As long as your eyesight is good, the level of oil should be very clear.