It's perfectly legit to use the layers
...even in a traditional sense it's kind of ok, considering that it's like working on a "totally dried up" canvas, so to say. And I love making at least one additive layer over top.
Very nice atmosphere (feeling) in that last one! It is quite inspiring, actually. I imagine a world that had lost its sunlight somehow, maybe by some slow moving planet that crosses over every 10,000 years and blocks most of the light for years. A tribe's shaman climbs the rock to request the return of the sun and thereby of the crescent moon as well, since both won't show in all that time. Cold comes over this world, an ice age they call winter of winters or the time of the jade moons. Ehh.... no,no,no, I stop right away, otherwise I let myself get carried away, haha... love it, though! Thanks!