Pencils are marked according to the hardness or softness of the lead. The 2B and the 2H sizes are the ones most used by artists for drawing and sketching. Many artists carry a small pack of colored pencils for quick sketches. Many types of erasers can be used, but the one most used by artists for professional work is the art gum, a kneaded eraser. The kneaded eraser is pliable and can be shaped by hand to erase the slightest tiny mark.
Watercolors are available in tubes or in trays of dry pigment cakes. Some watercolor artists carry a small set of dry pigments with them for spur of the moment paintings. Dry pigments, which are cakes of dry paint, are purchased in trays or sets. All that's needed for these is a wet brush. The tube colors may be preferred when working in the studio or at home as they have to be mixed with water.
Acrylic paints are available in tubes that are used on a palette with a wet brush. They produce art work that is very similar to oil painting pigments. They are also available in premixed 1 or 2 ounce bottles. Liquid acrylics are usually viewed as craft paint but are preferred by artists who want consistent color without having to mix them. Tube and liquid acrylics are normally used in the studio or at home.
Paint pens are convenient for artists doing craft work as the paint is permanent. They are not convenient for taking with you to do art work because of the time it takes for them to dry. Art markers are not used very often in creating pictures, but they are convenient for making signs and posters. Color pencils can be used anywhere, but they are normally used to make quick sketches that will be finished later at home.
Pre-stretched canvas on wood frames is used more often than the canvas boards, mainly because they are easier to hang. Many times they are hung alone without a frame. The flat board-type canvas must be framed. Sketch pads and watercolor paper come in a variety of sizes and paper weights. It is the artists' preference for the work being done as to which type of paper would be best. Small sketch pads are convenient to carry in a purse or book bag for quick drawings or studies.