// ensure that values are positive
                newR = Math.abs(newR);
                newG = Math.abs(newG);
                newB = Math.abs(newB);

                // ensure that values are not out of range
                if (newR > 255) {
                    newR = 255;
                }
                if (newG > 255) {
                    newG = 255;
                }
                if (newB > 255) {
                    newB = 255;
                }