Can anyone tell me if there are any written 'rules' for overlaying colours? I.e is there a specific sequence most professionals use once they have broken down what colours they need to use for a specific job. Ive had a it happen a few times to me now using water based acrylics where overlaying primary colours close together has ended up with a secondary i did not want, the most recent where i used some yellow and went too close with blue and ended up with the yellow going green on me. ... Looking at the above it sounds a bit of a confused post, i hope people understand what i mean.