A circuit found in many consumer viewing devices that attempts to compensate for the “Never Twice the Same Color” broadcast problems. This circuit can go far beyond the Auto Tint function in that it changes colour saturation as well as type of color. In most cases where ACC is present, it cannot be defeated. Adjusting the colour and tint controls, using the SMPTE colour Bar pattern and the blue philtre will result in a gross misadjustment of colour level on the set. The colour level may have to be reduced by as much as half the value calibrated with the SMPTE colour Bar pattern.