vals
values in [0,1]. The resulting interpolated color will be value*oneColor + (1-value)*zeroColor, in Lab space.
zeroColor
the "zero bound" color, in any valid R color format (e.g. "yellow", "#00FF00", ...)
oneColor
the "one bound" color, in any valid R color format (e.g. "yellow", "#00FF00", ...)