patterns were then "pounced" onto the board with a chalk filled pounce bag, marking the outlines of the figures or objects. Using oil paints, artists would use large brushes to paint the image. Once the panels were installed using hydraulic cranes, artists would go up on the installed billboard and touch up the edges between panels. These large, painted billboards were especially popular in Los Angeles where historic firms such as Foster & Kleiser and Pacific Outdoor Advertising dominated the industry. Eventually, these painted billboards gave way to graphic reproduction, but hand-painted billboards are still in use in some areas where only a single board or two is required. The "Sunset Strip" in Los Angeles is one area where hand-painted billboards can still be found, usually to advertise upcoming films or albums. Artists' Billboards Art exhibitions on a billboard or billboards are often referred to as artists' billboards or billboarding. These exhibitions are usually conducted by non-establishment Art curators, and feature non-establishment or emerging artists. Artists’ Billboards have been a key medium or vehicle to explore and express the ideas and strategies behind the most important art movements over the last fifty years: conceptualism, dematerialization, temporality, appropriation, authorship issues, socio-political critique, institutional critique, direct political engagement, such as defending the voices of minorities like women, gays, blacks, different ethnicities, etc., and postmodern concerns about the difference between reality and representation, among many others. Sometimes, the phrase "Look Up!" is used in press releases, by art news journalists, in the title of events, or informally, to describe these exhibitions that are literally in the sky. Digital billboards A digital billboard shows varying imagery and text created with computer programs and software. Digital billboards can be designed to display running text, have several different displays from the same company, or provide several companies a certain time slot during the day. Flexible and real-time scheduling can decrease traditional upkeep and maintenance costs, and some billboards may measure audiences or serve dynamic content. Using digital billboards dynamically has come to be known as programmatic out-of-home advertising. Billboard posters can play audio using conductive ink; when touched, the posters begin to play sounds. Mobile billboards Outdoor advertising, such as a mobile billboard, is effective because it is difficult to ignore. According to a UK national survey, it is also memorable. Capitol Communications Group found that 81.7% of those polled recalled images they saw on a