Snow appears simple to paint, but in actuality, the lack of detail becomes a source of frustration for some artists. Visually, the greatest problem that snow presents is its tendency to flatten an image, because it is nothing more than a flat, white blob on the canvas. This is especially problematic because artists painting landscapes generally rely on the depth and breadth of the scene to generate visual interest.
Select your landscape. Landscapes at different times of the day will have different tones in the snow. For example, a landscape on a cloudy afternoon will have more blues and greys, while a landscape with a spectacular sunset might present with warmer tones.
Study your landscape. What are the different colours you see in the snow? If you see nothing in the snow besides white, formless blobs, then assume you will be representing the snow with hints of grey. This will be your default colour for snow.
Set up your materials in a well-lit room where you can work undisturbed. Put on your smock and fill your jars with water for rinsing paintbrushes. Your canvas should be on a table or propped up in front of you, as should the image you are painting from.
Sketch onto your canvas a light outline of the objects in your landscape. Do not include details or textures.
Paint the larger blocks of colour. Do not worry very much about details. Cover the canvas quickly.
Go back into the objects in your painting once the paint has dried (unless you are using acrylic retarders, this should not take long). Make the edges harder and add some basic details. At this point, the areas of snow should appear to be formless, white blobs on the canvas.
Consider again the tones of colour on the snow in your landscape. Now on your palette, mix together a slather of titanium white with a dab of whatever other colours and tones you have identified in the snow. The colour you are mixing now will appear at the base of trees, houses, rocks and anywhere else on the painting where a shadow appears on the snow. This colour should be weak and delicate, and barely visible. It will be 98 to 99 per cent titanium white.
Add the colour you just mixed to the shadow areas on the snow. Blend it with the areas of pure white.
For deeper shadows, mix a small amount of blue or blue grey. Use your instincts. Adjust the shadows until they look right.
Add large objects to the foreground and very small objects to the background of your image wherever possible. This will help counteract the flattening-out effects that snow can have on a landscape.
Consider adding details to the snow, such as footprints disappearing into the distance or blades of grass poking up from beneath. This will enhance the snow visually and give it a greater sense of depth.
Note that red will have a stronger effect than any other colour you mix with white. If you are mixing red with white, start with a nearly imperceptible amount and add more as needed.