Blur Threshold - This is very useful for reducing noise and jpeg artifacts without blurring edge detail. Only pixels within a selected value and contrast range are blurred. The values of pixels 1, 3, 7, 9, in a 3x3 box are tested against pixel 5. If the differences are less than the threshold set for each channel, and the value within the range set by sliders 6-7, the new value returned for pixel 5 is an average of pixels 2, 4, 5, 6 and 8. Scale with controls 3-5. Correct color shift with Fade Filter set to luminosity mode.