I've been looking into this test for a couple of weeks now. In fact, it inspired my thread on converging the systems. I think the basic gist is that it is simply the four temperament theory with a new name. In the book, Hartman explains how that each person is really a blend of all four colors. Ironically, four colors with four different ordering of sequences brings us to 16, but they don't precisesly correspond to MBTI. Therefore, you're going to get an INFP, ISFJ, etc., scoring the same color, even when they're not alike, accept maybe they're both quiet and both have a tendency to care.
My aunt, who in MBTI is such an ES-J, that her police chief told her she was too curt during arrests, is a clear Red. But she also does have a caring side, so she scores a little blue (pencil and paper version allows more nuances.) She is big into this test. She likes how it's cut and dry and easy to remember. I don't. I think that it over-simplifies. In her mind, I was a Red before I ever took the test. She kept badgering me about it. I took the test and got 50/50 on my White and Blue scores, both out-weighing the Red by a large margin. She blew a gasket. How could her beloved test be so wrong? Surely, I didn't understand the questions.
Yes, that was it. So, she preceded to rescore me. I was clearly a Red in her eyes because, "Blues are whiny do-gooders and Whites are lazy pacifists." And I couldn't be those colors because I work hard and don't go around crying in front of people. So, my point in telling you this little snippet of personal history with this test is to say, "I don't really like it," or maybe more aptly, I don't like it in the hands of someone who insists on forcing people to "fit" a category whether they do or not.
She literally said, "Reds are the best people. So, you have to be a Red."