Filter Glass TypesSharp Cut Filters (L, Y, O, R)
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 259nm to 800nm.
Infrared Transmitting Filters (R, IR, RM)
Infrared-transmitting filters absorb most of the visible region and transmit the infrared region. They are widely used in light sources for such purposes as infrared warning systems and night-vision equipment.
Blue Filters (B)
Blue Filters transmit light in the blue spectrum and are named after the wavelength at which their transmittance attains the maximum value. They are used for 3-color separations, selection of wavelengths, and color compensation.
Green Filters (G)
Green filters transmit a relatively narrow wavelength band centered around light in the green spectrum and are named after the wavelength at which their transmittance attains the maximum value.
Light Balancing Filters (LA, LB)
Amber Filters (LA) are used to lower color temperature by shifting Mired value from +20 to +200. Blue Filters (LB) are used to raise color temperature by shifting Mired from -20 to -200.
Color Compensating Filters (C)
Color compensating filters control light in the blue, green, and red regions of the visible spectrum, and include the cyan series and magenta series.
Neutral Density Filters (ND)
These filters possess level spectral transmittance characteristics in the visible region, and are numbered with the average value of transmittances at 10nm steps in the 400nm to 700nm range.
Heat Absorbing Filters (HA)
These slightly bluish glass filters feature high transmittance in the visible region and good absorption of heat rays (infrared rays).
Ultraviolet Transmitting, Visible Absorbing Filters (U)
These are dark glass filters, nearly black, which transmit the ultraviolet region but absorb the visible spectrum. They transmit slightly in the near-infrared region.
Multiband Calibration Filters (V, H, Y)
V-10 and V-30 contain neodymium, and HY-1, holmium. All three filters exhibit outstanding absorption at specific wavelength. The filters are used for wavelength calibration and V-10 as a dual-color-type filter.