Daniel Smith's Lunar Blue is one of these paints. According to the amount of water you use, you get anything from a charcoal gray to robin's egg blue peppered with black speckles. It's a lovely paint, but one that takes a degree of practice to use reliably. How much water to you use to get the color you want? When you use so much water, it's hard to control the blossoms and backruns, so do you just use them, or keep trying to avoid them?
I've been playing with the color over the last few days, hoping to get a better feel for using it.
Once the initial wash died, I added more Lunar Blue, picking out the shapes, and kept adding more layers of the color until I was satisfied with my boulders. By this time, I knew I wanted the shallows of a stream.
Switching to my Yarka St. Petersburg pan set, I painted the fish with Titians. Then I mixed Lemon, Naples Yellow, and Raw Sienna into a thin brew, and stroked across the page, leaving areas where the Lunar Blue was uncovered.
Once that dried, I added Chromium Oxide Green where I wanted the impression of deeper, more opaque water. I finished off adding a little Cerulean Blue here and there.
Now, the problem with starting out with no plan is that something usually isn't quite right. In this case, I need some white ripples. I took an exacto knife and scraped a few. Then I broke the taboo about adding white, and used it to imply falls of water. I don't feel the least guilty about using white, either, so I've seen people hit the ceiling at the thought of such a thing, lol. I'm pleased with this piece, and I've learned something. Now, I can plan a similar work and more properly leave white or mask where I want to keep it.
I have two photos that I took at the Leach Gardens that I want to paint and now I have an idea how I'll do it.