I sometimes operate in to unpainted ceilings that have a heavier knock down that's a slightly distinct colour than the smooth base. Does give that two tone effect. Needed to do one a several years back in which the operator was all upset that painting would eliminate the two tone http://emilioaebyu.mybuzzblog.com/8293462/examine-this-report-on-so-painters-paint-interior-doors-in-a-new-construction