1. A computer-based image-manipulation method for enabling anti-clipping, selective user control over a color-affecting parameter in a computer-presented color image which is intended to be printed, where clipping is defined by the occurrence of an unintended condition, based upon user control input, wherein that parameter assumes a value which lies outside of a desired value range normally limited to values 0-255 in terms of a computer-recognized range of number values, said method comprising furnishing suitable computer-responsive, change-value color controls that are selectively manipulable by a user to effect changes, ultimately, in such a parameter value, thus to vary a certain characteristic of color in the image, and applying predetermined governance over the actual value of the color-affecting parameter, including implementing matrix processing of a user-chosen Chroma value, whereby, no matter the input control implemented by the user, that actual value is constrained in relation to approaching either one of the two limit values in the mentioned range to an asymptotic-like approach toward such limit value.