Gel mediums are versatile art supplies used in painting and mixed media. They are made from acrylic polymer emulsions and come in various consistencies, such as soft, regular, and heavy. Artists use gel mediums to modify the texture, transparency, and finish of their paints, allowing for creative effects and layering. These mediums can also act as adhesives, helping to bond materials like paper, fabric, or other objects to a surface. Additionally, gel mediums can be used to create three-dimensional textures on a canvas, making them popular among mixed media artists and collage creators.