The key to making anything three-dimensional is descriptive lighting. When trying to understand form, the brain focuses on the relationships between light and shadow in whatever it is that you're looking at.
With this in mind, painting trees and foliage with depth is about understanding the shape of what you're painting and then describing that shape with light – or the lack of it.
Choose a time of day and camera angle for the scene that have all the elements that you're looking for, and make sure you're closely using reference if any of this is new to you. Hopefully there's a location you can get to nearby that has some trees that you can take pictures of to use as reference. But if not, I'm pretty sure that the internet will have a few pictures of them that you could use!
'The Golden Hour' is a phrase you hear a lot in illustration, photography and cinematography. It refers to the first hour of sunrise and the last before sunset, when a low-hanging sun hits the planet with a strong side light. It's used extensively in all three fields, partially because that side light casts long, descriptive shadows.
Understanding the type of tree that you are painting, its trunk, its bark, and the shape of the leaves is all going to help tell the story as well.
01. All in the shadows
Pay careful attention to silhouettes. A big part of how our brains recognise objects is by their outline, and the silhouette of a tree speaks volumes about what sort of tree it is. The texture and gesture of each plant is greatly influenced by its two dimensional shape. Using different sized brushes with different tip shapes help distinguish contrasting edges.
02. Build it up
Now that the shadows are in place, it's time to start building up the light. Pay close attention to the direction of the light, and how reflective the surface of any given object may be. The way that the light hits it is what defines a tree’s volume. If it helps, imagine that the light source is a shower head, and everywhere the water touches is where the light shows up.
03. Throw some shapes
With the shadow and light in place, the picture should start to take shape. The relationship between the two is central to the composition, so don’t proceed until you're happy. Once everything begins to feel right we can move into more detail by adding in the darkest part of the shadows. Contrast tends to be softer in low-lit areas, so rendering isn't as much of an issue.
04. Take the edge off
Edges are an often-overlooked aspect of painting for newcomers, but considering your transitions will help bring out the depth in your image. If an edge feels too harsh, soften it. If transitions are too soft, try defining the edges more clearly. You can soften or sharpen with the Smudge tool, by changing the opacity, or with strict control of colour and value.
Words: Tony Foti