I use different dilution ratios for expansion and contraction.For example if I want to expand I use 1:4 for 13 minutes. If I want to contract I use 1:15 for 13 minutes, it saves a lot of hassle and is a lot easier to remember for this old head. You basically can use any dilution you want, as long as you make your testing. Good luck(posted 8525 days ago)