My "Color Relativity" course is on Udemy now. The video can be viewed online without the need of downloading the file to your computer. This is the 3rd class of my "Rigorous Color System for Artists". I have learned a lot by doing the research of color relativity. Human's color vision is so tricky. It varies all over the places when the viewing condition changes. I hope this course can help you to gain more control when you paint. Please visit: http://www.qh-art.com/online-teaching.html to access all versions of this course.