We present the dissolution characteristics of lac dye from lac resin. Lac samples of various mass M_L are agitated at various rates (ω) in different volumes of water (V_w) having various granule size (S_L ) and the concentration of dye in water was measured as a function of time. We show that the remaining amount of lac dye in the lac samples reduce exponentially with time. Time for achieving 30% of the initial mass of the dye in the lac sample (t₃₀) is seen to decrease with increase in surface area of the lac (S_L), agitation rate (ω) and the volume of the water. We obtain a relation for t₃₀ as t₃₀ω=f(ζ) where ζ=(C_(ⅆ_i ) ρ_L S_L v_w^(1/3))/M_L and f(ζ) is an exponential function. This relation could now be used to design intervention strategies in the washing process to improve the process.