"Pointillism" is a painting technique using dots of color to create images. You have likely seen such neo-impressionist paintings of Georges Seurat, Paul Signac and others. A new landscape scene brought to mind the pointillist approach and how it can be used to build "light on dark" layers in pastel.
The reference photo below presents a classic opportunity to build depth from the ground up. The portion of the ground in front of the tree stump has several layers: the brown dirt itself, decaying leaves, more recently dead leaves, then fresh green growth characterized by dark areas near the ground and bright areas as the foliage catches the sun.
First, I apply a series of points or blemishes in the pastel paper to reflect the earthy tones of the ground, mostly browns, orange and mauve. You can also see the cool blue used in the shadiest area.
Continuing to work in the shady area, I use a cool green blue Unison pastel for the shady undersides of the foliage in front of the tree stump. I also add a dark green to a few of the plant undersides.
Next, I jump to the sunlit area, and add the darker value green to the based of that foliage. Note that in the sun the green is a warmer green compared to the cooler blue-green used in the shade.
For my next step, I tone down the value of the strongly sunlit area with a foliage underside of a mid-value warm green.
Next, I apply the sunlit highlights of the foliage with a lighter value warm green pastel, and toss a bit in the shady area too.
In the image below, I apply further highlights to convey some of the glare of the sun off several of the leaves.
Here is the updated painting of this portion of the scene, and a more encompassing view of this landscape-in-progress below.
The "bigger picture:"