private static int decodeGray(char c)
    {
        // Check the char
        if (c == WHITE) {
            return  255;
        } else {
            for (int i = charTable.length -1; i >= 0; i--) {
                if (charTable[i] == c) {
                    int level = 2 + i * 36; // Range 2 .. 254 (not too bad)
                    return level;
                }
            }
        }

        // Unknown -> white
        return 255;
    }