You could add 'normalize => 0' arguments to the GetPixel call, and then get integers, most probably in 0 .. 0xFFFF range, because QuantumDepth of modern ImageMagick is 16 bit per channel by default. Even in the past, when it was 8 bit, you'd get integers 0 .. 0xFF, and certainly not strings in hexadecimal representation -- so basic arithmetic/formatting operation would be required for your purposes anyway.