30, 20, and 10 Years Ago in OPN

“Over the last 20 years the effectiveness of lasers for cleaning works of art has been established in a variety of applications. In the majority of cases, Nd:YAG lasers emitting 5–20 ns pulses in the near infrared (1.06 µm) have successfully removed surface encrustations from marble, limestone, and frescoes. … In contrast, successful laser conservation of paintings has only recently been achieved by using excimer lasers emitting nanosecond pulses in the ultra violet (193, 248, 308 nm). This is a particularly demanding application due to the delicate nature of paints and connecting media, which imposes severe limitations on the laser parameters used.”