A comparison is made of the light curves and and dust production of the initial target for the ROSETTA mission, 46P/Wirtanen and the new target 67P/Churyumov-Gerasimenko during their recent 2002/2003 apparition. The study is based on amateur CCD monitoring using a standardised method to produce consistent photometry in Johnson-Kron-Cousins system. Although the dust production of the two comets is similar at perihelion (Af ho ≈200-cm), dust production in 46P/Wirtanen peaked before perihelion, while in 67P/Churyumov-Gerasimenko it peaks after perihelion. Dust activity shows the same post-perihelion dependence with heliocentric distance in both comets. Overall 67P/Churyumov-Gerasimenko has a dust production rate an order of magnitude greater at the same heliocentric distance post-perihelion as 46P/Wirtanen, but 46P/Wirtanen has greater maximum dust production immediately prior to perihelion.