Filter factor is approx. Due to the slight yellow coloring of this filter, it is designed for aerial photography with black and white film. Filter factor is approx. This filter is used to differentiate reproductions of green tones in reproduction photography. It may also be used to create the effect of haze.
Filter factor is approx.
It is especially recommended for CCD applications where digital image sensors have not been fitted with an IR protection filter. Although this dark-violet filter transmits a small amount of visible light, it completely blocks wavelengths longer than 360nm. Depending on the film, the filter factor is between 8 and 20. This filter is frequently described as a heat absorbing filter because it lets the visible spectral range pass while the infrared rays from 780nm are strongly blocked. It is often used to protect IR-sensitive CCD sensors or in illumination systems.