The color spectrum of a rainbow is in the order
of: red, yellow, green, blue, violet.
We see red light from the higher drops because it is directed towards the observer's eyes. Violet light is directed above the level of the eyes so we do not see it.
In the lower drops red light is directed below the eye level and violet light is visible to the observer. This is why we see the colors of the primary rainbow change from red to violet in the order from top to bottom.
the double rainbow is formed the double
reflection also forms an color spectrum but it is reversed. The double rainbows color order is(from top to bottom): Violet, blue, green, yellow, red. It looks just like a mirror image of the primary rainbow. In this picture you can see that the red is visible in the lower drops and the violet is visible in the higher drops. The exact opposite of the primary rainbow explanation.