Layout markers are professional grade markers used by artists, illustrators, animators, designers, engineers, and architects, as well as hobbyists, often for illustrations, storyboards, or technical drawings. Some layout markers are waterbased, others solvent based. Layout markers are available in many colors and shades of gray.
With markers, the designation "permanent" means that the ink cannot be washed off with water. Permanent markers are indelible, but not necessarily lightfast or even fade-resistant.
Permanent markers use a solvent-based ink, and with some brands this solvent is toxic. Read labels and instructions carefully.
Water-based markers use a water-soluble ink, and they are generally non-toxic, but not necessarily washable. Read instructions carefully. If you must have a washable marker, select one that specifically features washability. Many brands are designed to be easy to wash off skin or clothing, and are suitable for children.
Archival markers contain pigments rather than dyes, however colors other than black may fade over time with exposure to ultraviolet light. Archival markers are acid-free, and will not damage the underlying surface. This makes them suitable for marking on photographs, fine art prints, and so forth.
Paint markers use opaque inks, and are often designed for large areas of coverage. However, they don't contain actual paint. Some are solvent-based and permanent, others water-based.
Calligraphy markers are marking pens with one or more special tips that can create the same effects as a calligraphy or lettering pen.
Markers are a great tool, but they are generally not for creating permanent works of art. Use markers to create quick sketches. They are faster and more convenient than any other medium. They dry quickly, and work well on any smooth paper surface. But even archival markers are not necessarily lightfast, so if you want to save it, scan it.