Also gels, a thin translucent filter placed in front of the light, can be used to filter the light and adjust its color temperature. CTB (Color Temperature Blue) will shift the temperature of a tungsten light to daylight color (5600K). CTO (Color Temperature Orange) will shift the temperature of a daylight light source to tungsten (3200K). These filters are also available in 1/2 and 1/4 that will shift the temperature to that direction but only of a certain fraction of the total shift.