The main characteristic of charcoal as a medium is that, unless it is fixed by the application of some form of gum, resin or spray, it is impermanent, easily erased or smudged.
Oil pastel colours are rich, creamy, and intense. Oil pastel sticks are stronger and harder than soft pastels, so line weight can be varied to create more expressive lines by applying more or less pressure to the drawing or painting surface.
The main advantages of oil paints are their flexibility and depth of colour. They can be applied in many different ways, from thin glazes diluted with turpentine to dense thick impasto. Because it is slow to dry, artists can continue working the paint for much longer than other types of paint.
Acrylic paint is one of the most versatile mediums, and one of the least toxic. It is water-soluble when wet and yet because it is a plastic polymer, dries into a flexible, water-resistant, and durable surface to which subsequent layers of paint can be added without disturbing the underlying layers.
Watercolour or watercolour, also aquarelle, is a painting method in which the paints are made of pigments suspended in a water-based solution. Watercolour refers to both the medium and the resulting artwork.