Sharp Cut Filters
Sharp cut filters include 15 types, ranging from L-37 to R-66. The L, Y, O and R symbols represent Colorless, Yellow, Orange, and Red tones of filter color respectively. The numerals used to classify the glass types indicates 1/10 the corresponding transition wavelength.
Since the filters L-42 to R-68 are of "striking glass", the spectral characteristics of the filters will vary even if the striking temperature is controlled.
According to the Japanese Industrial Standard JIS B 7113 "Sharp cut filters" are defined as "Filters that cut off as much as possible of the wavelength light shorter than a specific wavelength, while transmitting as much of longer wavelength light as possible, within a wavelength range of 350nm to 800nm."
These Filter Types are generally used in Photography Applications, and are available in 2.5mm thickness.