Landscape painting captures the vibrant colours of outdoor scenes on canvas with paint and brush. When painting a blue sky and green grass in an outdoor scene, it is important to understand colour. The sky is not just one big, blue block; on the contrary, a blue sky is made up of many shades of blue and even white. Grass is similar in nature, containing yellow, brown and even blue undertones. You can paint a convincing blue sky and natural-looking green grass with just a few basic techniques.
Pencil in the horizon line, which is the line where the grass and the sky meet. Make the horizon line straight or mountainous.
Squeeze a small amount of ultramarine blue paint onto the paint palette. Squeeze a larger amount of white onto the palette.
Mix a small amount of ultramarine with white, using the palette knife, until you have a very light (almost white) blue colour.
Use a medium-sized flat brush to paint along and slightly above the horizon line. Skies are lighter in colour closer to the horizon line.
Mix more ultramarine paint in with the light blue until it is one or two shades darker than the previous blue. Paint above the lighter blue with the darker blue, blending the colours together where they meet.
Repeat Step 5 for each "layer" of sky. The sky will be a medium shade of blue at the very top of the painting. Make sure each layer is well blended into one another for the smoothest appearance.
Dip the ends of a fan brush into the white paint, and lightly dab against chosen areas of the sky to represent clouds. Make the clouds puffy or wispy. Let the clouds blend with the blue of the sky for the most natural appearance. Let the sky dry.
Squeeze a large amount of veridian and a small amount of light cadmium yellow onto the paint palette. Mix the yellow with the veridian until you have a deep yellow-green colour.
Paint the entire grass area with the yellow-green shade, using short, upward strokes with the hog-bristle brush. This is the underpainting.
Mix a small amount of white with the yellow-green until it is one or two shades lighter.
Paint individual grass blades scattered throughout the underpainting, using short, upward strokes with a thin, round brush. Mix more yellow with the lighter shade of green, and create more individual blades in the same manner. Scattering random individual blades combined with the bristle brush strokes of the underpainting creates the illusion of grass.
Lightly drag a fan brush over the blue sky to smooth it out while the paint is still wet. Create more individual blades of grass closer to the foreground. As the grass goes further back towards the horizon, individual blades aren't visible, and the grass has a blurred, smudgy appearance. Mix more white with grass that recedes far into the background. Background objects are lighter than foreground objects. Use a photograph of a landscape as a reference while painting to give yourself a better idea of what the final piece should look like.