A limited palette painting which is given vibrancy by allowing the raw colours of the underpainting to show through in several places. I do this very often in landscape paintings where there are large areas of what appears to be the same colour. A field of grass is one such example. I would not try and paint every blade of grass individually. This certainly would add interest and texture, if I lived long enough to complete it.
Paint can be applied in 2 ways over an underpainting to allow it to effect the final appearance.
Method 1 (Glazing): If the under colour is light in colour, as Yellow Ochre, a glaze can be applied when the yellow is thoroughly dry. This is usually a dark transparent colour, like Burnt Sienna, which is painted as a flat even layer allowing the variations in the underpainting to be seen. The resultant combination will be a mix of the two colours, but a colour which almost glows. The physical mixing of these colours will be a far less vibrant. The lighter colour underneath in the glaze reflects the light back through the upper layer and this is why it works better with the lighter colour underneath.
Method 2 (Scumbling): In this painting, the second method is used. This is a more flexible method as a lighter colour can be applied over a darker colour and visa versa. The underpainting does not have to be completely dry, so it suits the alla prima painter. Its not like glazing. in that the upper layer does not completely cover the lower layer. Because of this the upper colour can be non transparent. This mix is dragged lightly over the underpainting leaving the under colour in the lower texture of the canvas, uncovered.
In this painting, Prussian Blue was applied in the sky and the foreground. In the sky a lighter colour mix of Cerulean Blue, Prussian Blue, Yellow Ochre and white was dragged across the darker raw Prussian Blue. Later blending did cover the underpainting in places, but enough raw colour in the underpainting was left to give a variety and interest to the otherwise flat blue of the sky. In the foreground, a dark mix of Burnt Sienna, Raw Umber and Prussian Blue was dragged across the raw Prussian Blue underpainting but not covering it completely. Here, the fine brush used to paint in the grasses did cause a little blending of upper and lower colour, but the raw Prussian Blue can still be seen.
Here is the video of the process.