Color Temperature Blue (CTB) correction gels are calibrated to raise color tempreature to 5500 Kelvin (Daylight).
• They are availble in several strengths and are primarily used to correct Tungsten (3200 Kelvin)to Daylight.
••• CTB (Full Blue) raises 3200 Kelvin to 5500 Kelvin.
••• 3/4 CTB (Three-Quarter Blue) raises 4700K to 5500K.
••• 1/2 CTB (Half Blue) raises 4100K to 5500K.
••• 1/3 CTB (Third Blue) raises 3800K to 5500K.
••• 1/4 CTB (Quarter Blue) raises 3500K to 5500K.
••• 1/8 CTB (Eighth Blue) raises 3300K to 5500K.