It takes time to see more colors. Many people stop training when they start seeing like a meter or so, thinking that's all there is to it, but auras can expand for much, much more, especially if the person meditates.
In general keep this in mind, this is an intuition I had. "When you think you have obtained all the Power there was to obtain, that's the moment your journey towards True Power ends. The moment you think you obtained all the Knowledge there was to obtain, that's the moment your journey towards True Knowledge ends".
The human potential for spirituality is insane, I'm starting to think that there are no limits at all, as long as one keeps working. The thing is that we are used to having no power and no spiritual experiences all our lives, and when we start having some here and there, we think that's all there is to it, but it's not even 1%. The person who always keeps seeking for more will realize this, while all the others will keep living in the illusion that they are "gods" on earth and that they've reached their potential or most of it.