Typography is the art and technique of arranging type, type design and modifying type glyphs. The type glyphs are created and modified using a variety of illustration techniques. The arrangement of type involves the selection if typefaces, point size, line length, leading, adjusting the spaces between groups of letter and adjusting the space between pairs of letters. Typography is performed by typesetters, compositors, typographers, graphic designer, art director, comic book artists and graffiti artists. Until the digital age, typography was a specialised occupation. Digitisation opened up typography to new generations of visual designers and lay users.