The history of the Panerai Luminor is similar to that of the Radiomir, since its name was also derived from the luminescent paint compounds that were used at one time on the markers. The actual word "Luminor" was trademarked by Panerai after it reformulated its glowing dial paint in 1949, which replaced its previously used and more toxic and radioctive glow-in-the-dark paint Radiomir. In the early 1950s, both the Radiomir and Luminor designs existed side by side, until the Luminor eventually replaced its predecessor. Today, both Radiomir and Luminor models coexist and are the core of Panerai's line lf luxury watches. Modern Panerai Luminor designs now include the Base, Marina and GMT models that come in 40mm to 44mm sizes, as well as other special, premium editions (in tribute to vintage models).