convert rgb to cmyk to rgb

rgb-cmyk-rgb-conversion

def rgb_to_cmyk(r,g,b):

    cmyk_scale = 100

    if (r == 0) and (g == 0) and (b == 0):
        # black
        return 0, 0, 0, cmyk_scale

    # rgb [0,255] -> cmy [0,1]
    c = 1 - r / 255.
    m = 1 - g / 255.
    y = 1 - b / 255.

    # extract out k [0,1]
    min_cmy = min(c, m, y)
    c = (c - min_cmy) / (1 - min_cmy)
    m = (m - min_cmy) / (1 - min_cmy)
    y = (y - min_cmy) / (1 - min_cmy)
    k = min_cmy

    # rescale to the range [0,cmyk_scale]
    return c*cmyk_scale, m*cmyk_scale, y*cmyk_scale, k*cmyk_scale


def cmyk_to_rgb(c, m, y, k):
    cmyk_scale = 100

    c = c / cmyk_scale
    m = m / cmyk_scale
    y = y / cmyk_scale

    #c = -(c + -(k))

    c = c * (1-k) + k
    m = m * (1-k) + k
    y = y * (1-k) + k

    r = (1-c) * 255.
    g = (1-m) * 255.
    b = (1-y) * 255.


    return r, g, b