The Kodak 75 x 75mm CC40B Filter is a blue color compensating filter that helps to control color balance by attenuating the red and green portions of the visible spectrum. By placing this filter in front of or behind the lens, you can alter the color balance of imagery or compensate for deficiencies in the spectral quality of a light source.
The CC40B-density filter requires a 1.3 stop increase in exposure for normal results. Wratten 2 filters are constructed from gelatin for ease of use and consistent performance. When compared to original Wratten filters, Wratten 2 filters are more rigid and durable, easier to handle, and less sensitive to humidity, static cling, and fingerprints.