Completeness expected in the ERO-Fornax catalogue data based on artificial GCs. Top panel: combined completeness for sources detected in both I_E and Y_E as a function of simulated input I_E magnitude. Bottom: detection completeness in the four individual filters as a function of the respective input magnitude. For old GCs (older than 7 Gyr) with sub-solar metallicities (Z < 0.02), the GCLF turn-over magnitude is expected to be at I_E = 23.5.