SilverFast ACR is part of the Selective Color Correction dialog. A checkbox will enable this function to bring back faded out colors or normalize over-saturated colors. A slider will give additional individual control to increase or decrease color saturation.
Adaptive Color Restoration nicely brings back the faded out colors or weak colors with an automatic function. The function's strength can be controlled with a slider. Also too much saturation can be normalized or decreased.
ACR can also be used in conjunction with the Selective Color Correction. Any setting that has been chosen can now be influenced with the ACR function (e.g. if you have chosen your corrections but want more or less saturation), just use the ACR slider. The relation, between the color as defined by your Selective Color Corrections setting, will be kept.