GCR option giving error#6

h.make() is working, but as soon as I am adding the GCR % as an option the following error is occuring: h.make(percentage=50) Traceback (most recent call last): File "<input>", line 1, in <module> File "C:\Users\shank\Documents\Documents\Halftone\halftone.py", line 63, in make cmyk = self.gcr(im, percentage) File "C:\Users\shank\Documents\Documents\Halftone\halftone.py", line 88, in gcr cmyk[i][x, y] = cmyk[i][x, y] - gray TypeError: color must be int or tuple  Can you please help me solve this issue. Also is there any way I could view and save individual C, M, Y, K channels instead of the composite file. Thanks.