Acording to the ASTM Standards Organization, a colored pencil's lightfast rating is defined by how resistant the color is to the fading effects of light. Colors with a strong lightfast rating will maintain vibrancy in the presence of light, while colors with a weak lightfast rating will readily fade or change color over time. In the tradition of Prismacolor, each lightfast colored pencil has a soft, thick core to deliver the smooth, creamy laydown of coor that artists expect.
The American Society for Testing and Materials (ASTM Organization), in collaboration with the Colored Pencil Society of America (CPSA), developed the ASTM D6901 standard for colored pencil lightfastness. Prismacolor Premier Lightfast Colored Pencils fully comply with the ASTM lightfast standard.