When speaking of combining colors, it is a bit risky to establish a strict standard. There are a number of tricks and tips that you can follow to establish a suitable combination. If we set an example, we can say that more than 3 colors can be too if there is great contrast between them, but in turn can form a nice combination and always when the ratio and proportion that we will use is adequate:
• The soft, neutral color is applied in more than 60% of the stay.
• The deeper color should not occupy more than 15% of the stay.
• The color transition: the best ratio is 25-30%, for mediating between the 2 above.