Final answer:
Pastel is a friable medium consisting of powdered pigment and binder, creating subtle tonal effects and is commonly fixed with a spray to prevent smudging. It is distinct from other painting mediums like oil painting, watercolor, and gouache, each possessing unique characteristics and methods of application.
Step-by-step explanation:
Pastel is a friable medium that requires as support colored paper. This medium is typically known for its powdery texture and the ability to blend colors to create soft, subtle changes in tone. Pastels consist of a finely ground powdered pigment bound together with a binder, allowing artists to achieve a resonance and depth that may be more challenging with other mediums such as graphite or charcoal.
When looking at artworks like Picasso's Portrait of the Artist's Mother, you can observe the blending qualities of pastels, especially in the skin areas, where they give an effect similar to an oil painting. Unlike other friable mediums like chalk, which are less easily blended, pastels can create a rich, painterly appearance on more textured paper that has a 'tooth' to catch the pigment. These works are often fixed with a protective spray to prevent smudging.
Contrastingly, other painting mediums, such as oil painting, watercolor, and gouache, have different properties and supports. Oil paintings, for instance, are known for their thick impasto techniques and slower drying times, while watercolors are appreciated for their transparency and sensitivity to brushwork. Gouache, an opaque watercolor, contains larger particles of pigment and typically includes chalk to give it a more solid appearance.