The layer with blues and greens are environmental colour. I must say I'm still learning and I'm not 100% sure what I am doing. I’m just applying these colours according to how I feel😅
I used orangy brown for the reflection from the earth, blue from the sky, purple supposed to go well with shading and dark colour and teal at the edges where light is hitting. You can hardly see these colour on the completed art work but I like how blue and teal show though so I tend to leave them uncoloured at the next layer on purpose.