driving pinion 211 thus providing a gearing increase such a gearing system may be advantageous for reasons of speed of movement however it is not a requirement for the present invention in the embodiment illustrated the first driven pinion 223 is fixed to axle 228 and second driven pinion 224 is free to rotate around axle 228 axle 228 is free to rotate in bearings 225 and 227 mounted in the top and bottom support plates 202 and 203 respectively the mountings of the bearings in the support plates is rigid providing secure support for the axle 228 at both ends which in turn provides a backlash and vibration free support for the driven pinion 223 a flag support arm 229 is attached to the driven pinion 224 each flag support arm supports a color mixing filter flag 205 215 206 216 the color mixing filter flags are mounted in pairs of the same color thus 205 and 215 are one color and 206 and 216 are a second different color for example one half of each flag pair 206 is mounted on a driven pinion 223 and the second half of each flag pair 216 for example is mounted on the associated driven pinion 224 in this manner each axle supports two driven pinions for two different colors each axle will have on one end a driven pinion which is fixed to axle and has a flag of a first color and at the other end.